US20080205904A1 - Electric Field Sensor Device, Transceiver, Positional Information Obtaining System, and Information Input System - Google Patents
Electric Field Sensor Device, Transceiver, Positional Information Obtaining System, and Information Input System Download PDFInfo
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- US20080205904A1 US20080205904A1 US12/111,866 US11186608A US2008205904A1 US 20080205904 A1 US20080205904 A1 US 20080205904A1 US 11186608 A US11186608 A US 11186608A US 2008205904 A1 US2008205904 A1 US 2008205904A1
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- Prior art keywords
- electric field
- laser light
- signal
- transceiver
- light
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B13/00—Transmission systems characterised by the medium used for transmission, not provided for in groups H04B3/00 - H04B11/00
- H04B13/005—Transmission systems in which the medium consists of the human body
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B13/00—Transmission systems characterised by the medium used for transmission, not provided for in groups H04B3/00 - H04B11/00
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
- G06F1/16—Constructional details or arrangements
- G06F1/1613—Constructional details or arrangements for portable computers
- G06F1/163—Wearable computers, e.g. on a belt
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
Definitions
- the present invention relates to a transceiver that is used to carry out data communications between wearable computers, for example. More particularly, the present invention relates to a transceiver that can receive information via an electric field transmission medium by receiving information based on an electric field induced in the electric field transmission medium.
- the present invention further relates particularly to a transceiver including a transceiver main body that can transmit information via an electric field transmission medium by inducing an electric field based on the information to be transmitted from a transmitting electrode to the electric field transmission medium, a battery that drives the transceiver main body, and an insulating case that incorporates the transceiver main body.
- the present invention further relates to an electric field sensor device that detects an electric field by modulating the optical intensity of laser light based on an electric field to be detected, and a transceiver that has the electric field sensor device.
- the present invention further relates to positional information obtaining system including electric field inducing means for inducing an electric field in an electric field transmission medium corresponding to a position at which the electric field inducing means is brought into contact with the electric field transmission medium, and a transceiver that obtains information at the above position by receiving the electric field induced in the electric field transmission medium and converting the electric field into an electric signal.
- the present invention further relates to an information input system that obtains information based on positional information and the like from the positional information obtaining system.
- FIG. 1 shows an image of carrying out communications between plural wearable computers via a human body.
- a wearable computer 1 and a transceiver 3 ′ that is brought into contact with the wearable computer 1 constitute one set.
- a set of a wearable computer 1 and a transceiver 3 ′ can carry out data communications with other set of a wearable computer 1 and a transceiver 3 ′, via a human body.
- the wearable computer 1 can also carry out data communications with other set of a personal computer (PC) 5 which is other than the wearable computer 1 mounted on the human body and a transceiver 3 ′ a installed on a wall or the like, or a set of the PC 5 and a transceiver 3 ′ b installed on a floor or the like.
- PC personal computer
- the PC 5 is not brought into contact with the transceivers 3 ′ a and 3 ′ b unlike the wearable computer 1 and the transceiver 3 ′, but is connected via a cable 4 , to the transceivers 3 ′ a and 3 ′ b.
- a signal detection technique according to an electro-optic method using a laser light and an electro-optic crystal is utilized.
- an electric field based on information (data) to be transmitted is induced in a human body (i.e., electric field transmission medium), and information based on the electric field induced in the human body is received, thereby achieving transmission and reception of the information.
- the technique of data communications via the human body is explained in detail with reference to FIG. 2 .
- FIG. 2 is an overall configuration diagram of a transceiver main body 30 ′ that is used to carry out data communications via a human body 100 .
- the transceiver main body 30 ′ is used in a state of being in contact with the human body 100 via a transmitting and receiving electrode 105 ′ and an insulating film 107 ′.
- the transceiver main body 30 ′ receives data supplied from the wearable computer 1 via an I/O (input/output) circuit 101 , and transmits the data to a transmitter 103 .
- the transmitter 103 induces an electric field in the human body 100 as an electric field transmission medium from the transmitting and receiving electrode 105 ′ via the insulating film 107 ′.
- the transmitter 103 transmits this electric field to other transceiver 3 ′ mounted on other part of the human body 100 via the human body 100 .
- the transmitting and receiving electrode 105 ′ receives an electric field induced in the human body 100 and transmitted from a separate transceiver 3 ′ mounted on other part of the human body 100 via the insulating film 107 ′.
- An electric field sensor unit 110 ′ that constitutes an electric field sensor device 115 ′ applies the received electric field to the above electro-optic crystal, thereby generating a polarization change and an intensity change in the laser light.
- a light receiving circuit 152 ′ that constitutes the electric field sensor device 115 ′ receives the polarization-changed and intensity-changed laser light, and converts the laser light into an electric signal, and processes this electric signal such as amplifies this electric signal.
- a signal processing circuit 116 that constitutes a receiver circuit 113 removes a frequency component other than a frequency component concerning reception information as the electric field to be detected out of electric signals of various frequencies (i.e., extracts only the frequency component concerning the reception information) with a band pass filter that constitutes the signal processing circuit 116 , thereby removing noise from the electric signal.
- a waveform shaping circuit 117 that constitutes the receiver circuit 113 shapes the waveform (i.e., carries out a signal processing) of the electric signal that passes the signal processing circuit 116 , and supplies the waveform-shaped electric signal to the wearable computer 1 via the input/output circuit 101 .
- the electrode can be divided into two for transmission and for reception, respectively.
- the transmitter 103 induces an electric field in the human body 100 as an electric field transmission medium from a transmitting electrode 105 ′ a via an insulating film 107 ′ a.
- a receiving electrode 105 ′ b receives an electric field induced in the human body 100 and transmitted from a separate transceiver 3 ′ mounted on other part of the human body 100 via an insulating film 107 ′ b.
- Other configurations and their operation are similar to those shown in FIG. 2 .
- the wearable computer 1 mounted on the right arm makes the transceiver 3 ′ induce an electric signal concerning transmission data as an electric field in the human body 100 as an electric field transmission medium, and transmit the electric field to other parts of the human body 100 as shown by a wavy line.
- the wearable computer 1 mounted on the left arm can make the transceiver 3 ′ receive the electric field transmitted from the human body 100 , return the electric field to the electric signal, and receive reception data.
- the computer such as the wearable computer 1 and a personal digital assistant such as a portable telephone need to be compact considering convenience of mounting on the human body 100 and carrying as shown in FIG. 1 .
- the electric field sensor unit 110 ′ in the transceiver main body 30 ′ includes ones which convert the polarization change of laser light into the intensity change like a polarization modulator, and ones which directly convert the intensity change of the laser light like optical intensity modulators such as an electroabsorption (EA) optical intensity modulator and a Mach-Zehnder optical intensity modulator.
- EA electroabsorption
- Mach-Zehnder optical intensity modulator Mach-Zehnder optical intensity modulator
- An electric field sensor unit 110 ′ a and a light receiving circuit 152 ′ a that use a polarization modulator 123 is explained with reference to FIG. 4 and FIG. 5 , and then, an electric field sensor unit 110 ′ b and a light receiving circuit 152 ′ b that use an optical intensity modulator 124 is explained with reference to FIG. 6 to FIG. 8 .
- the electric field sensor unit 110 ′ a using the polarization modulator 123 includes a current source 119 , a laser diode 121 , a lens 133 , the polarization modulator 123 such as an electro-optic element (electro-optic crystal), a first and a second wave plates 135 and 137 , a polarizing beam splitter 139 ′, and a first and a second lenses 141 a and 141 b.
- the light receiving circuit 152 ′ a includes a first photodiode 143 a , a first load resistor 145 a , a first constant voltage source 147 a , a second photodiode 143 b , a second load resistor 145 b , a second constant voltage source 147 b , and a differential amplifier 112 .
- the polarization modulator 123 has sensitivity in only the electric field that is coupled in a direction perpendicular to a proceeding direction of laser light that is emitted from the laser diode 121 .
- the intensity of the electric field changes optical characteristic, that is, a birefringence index, of the polarization modulator 123 .
- the change of the birefringence index of the polarization modulator 123 changes the polarization of the laser light.
- a first electrode 125 and a second electrode 127 are provided on both side surfaces of the polarization modulator 123 , that are opposite in a vertical direction in the drawing.
- the first electrode 125 and the second electrode 127 face each other perpendicular to the proceeding direction of the laser light from the laser diode 121 in the polarization modulator 123 , and can couple the electric field with the laser light at a right angle.
- the electric field sensor unit 110 ′ a is connected to the receiving electrode 105 ′ b via the first electrode 125 .
- the second electrode 127 that is opposite to the first electrode 125 is connected to a ground electrode 131 , and functions as a ground electrode to the first electrode 125 .
- the receiving electrode 105 ′ b detects an electric field that is transmitted after being induced in the human body 100 , transmits this electric field to the first electrode 125 , and can couple the electric field with the polarization modulator 123 via the first electrode 125 .
- the laser light output from the laser diode 121 according to the current control from the current source 119 is made parallel light via the lens 133 .
- the first wave plate 135 adjusts the polarization state of the parallel laser light, and inputs the laser light to the polarization modulator 123 .
- the laser light that is incident to the polarization modulator 123 is propagated between the first and the second electrodes 125 and 127 within the polarization modulator 123 .
- the receiving electrode 105 ′ b detects the electric field that is transmitted after being induced in the human body 100 , and couples this electric field with the polarization modulator 123 via the first electrode 125 .
- the electric field is formed from the first electrode 125 toward the second electrode 127 connected to the ground electrode 131 . Since the electric field is perpendicular to the proceeding direction of the laser light that is incident from the laser diode 121 to the polarization modulator 123 , the birefringence index as the optical characteristic of the polarization modulator 123 changes, and the polarization of the laser light changes accordingly.
- the second wave plate 137 adjusts the polarization state of the laser light of which polarization is changed by the electric field from the first electrode 125 in the polarization modulator 123 , and inputs the laser light to the polarizing beam splitter 139 ′.
- the polarizing beam splitter 139 ′ separates the laser light input from the second wave plate 137 , into a P wave and an S wave, and converts the laser light into optical intensity change.
- the first and the second lenses 141 a and 141 b condense respectively the laser light that is separated into the P wave component and the S wave component by the polarizing beam splitter 139 ′.
- the first and the second photodiodes 143 a and 143 b that constitute photoelectric converting means receive the laser light, convert the P wave light signal and the S wave light signal into electric signals respectively, and output the electric signals.
- the first load resistor 145 a , the first constant voltage source 147 a , the second load resistor 145 b , and the second constant voltage source 147 b convert the current signals output from the first and the second photodiodes 143 a and 143 b , into voltage signals.
- the differential amplifier 112 can extract a voltage signal (intensity modulation signal) concerning reception information by differential. The extracted voltage signal is supplied to the signal processing circuit 116 shown in FIG. 2 and FIG. 3 .
- the phase of a voltage signal Sa according to the first photodiode 143 a and the phase of a voltage signal Sb according to the second photodiode 143 b are deviated by 180 degrees. Therefore, the differential amplifier 112 amplifies the signal component of the opposite phase, and subtracts and removes noise of the in-phase laser light.
- the signal processing circuit 116 shown in FIG. 2 and FIG. 3 removes noise from the signal.
- the waveform shaping circuit 117 shapes the waveform of the signal, and supplies the signal to the wearable computer 1 via the input/output circuit 101 .
- the electric field sensor unit 110 ′ b and the light receiving circuit 152 ′ b that use the optical intensity modulator 124 is explained with reference to FIG. 6 to FIG. 8 .
- Constituent parts identical with those of the electric field sensor unit 110 ′ a and the light receiving circuit 152 ′ a that use the polarization modulator 123 are assigned with the same reference numerals.
- the electric field sensor unit 110 ′ b that uses the optical intensity modulator 124 includes the current source 119 , the laser diode 121 , the lens 133 , the optical intensity modulator 124 such as an electroabsorption (EA) optical intensity modulator and a Mach-Zehnder optical intensity modulator, and the lens 141 .
- the optical intensity modulator 124 such as an electroabsorption (EA) optical intensity modulator and a Mach-Zehnder optical intensity modulator
- EA electroabsorption
- the light receiving circuit 152 ′ b includes the photodiode 143 , the load resistor 145 , the constant voltage source 147 , and a (single) amplifier 118 .
- the optical intensity modulator 124 is configured to change the optical intensity of the light that passes due to the intensity of the coupled electric field.
- the first electrode 125 and the second electrode 127 are provided on both side surfaces of the optical intensity modulator 124 , that are opposite in a vertical direction in the drawing.
- the first electrode 125 and the second electrode 127 face each other perpendicular to the proceeding direction of the laser light from the laser diode 121 in the optical intensity modulator 124 , and can couple the electric field with the laser light at a right angle.
- the electric field sensor unit 110 ′ b is connected to the receiving electrode 105 ′ b via the first electrode 125 .
- the second electrode 127 that is opposite to the first electrode 125 is connected to the ground electrode 131 , and functions as a ground electrode to the first electrode 125 .
- the receiving electrode 105 ′ b detects an electric field that is transmitted after being induced in the human body 100 , transmits this electric field to the first electrode 125 , and can couple the electric field with the optical intensity modulator 124 via the first electrode 125 .
- An electroabsorption (EA) optical intensity modulator 124 a as one example of the optical intensity modulator 124 is briefly explained with reference to FIG. 7 .
- the electroabsorption optical intensity modulator 124 a varies the optical intensity according to the detection signal concerning the electric field with the constant optical intensity as the maximum. In other words, the intensity of the input laser light is attenuated based on the detection signal concerning the electric field.
- a Mach-Zehnder optical intensity modulator 124 b as one example of the optical intensity modulator 124 is briefly explained with reference to FIG. 8 .
- the Mach-Zehnder optical intensity modulator 124 b has two waveguides 203 a and 203 b having light refraction indexes different from that of a substrate 201 formed on the substrate 201 , thereby confining laser light input via a lens 205 within the waveguides 203 a and 203 b and branching the laser light.
- the first electrode 125 and the second electrode 127 apply an electric field to one of the branched laser lights and couple the electric field with the laser light.
- the Mach-Zehnder optical intensity modulator 124 b emits the laser light via the lens 207 .
- the phase of this laser light can be slightly delayed or advanced from that of the laser light which is not applied with the electric field.
- the laser light output from the laser diode 121 based on the current control by the current source 119 is made parallel light via the lens 133 .
- the parallel laser light is incident to the optical intensity modulator 124 .
- the laser light that is incident to the optical intensity modulator 124 is propagated between the first and the second electrodes 125 and 127 within the optical intensity modulator 124 .
- the receiving electrode 105 ′ b detects the electric field that is transmitted after being induced in the human body 100 as explained above, and couples this electric field with the optical intensity modulator 124 via the first electrode 125 . Then, the electric field is formed from the first electrode 125 toward the second electrode 127 connected to the ground electrode 131 .
- the photodiode 143 of the light receiving circuit 152 ′ b receives the laser light via the lens 141 .
- the photodiode 143 converts the laser light into a current signal according to the optical intensity of the laser light.
- the load resistor 145 and the constant voltage source 147 convert the current signal output from the photodiode 143 into a voltage signal, and output this voltage signal.
- the output voltage signal is amplified by the amplifier 118 , and is supplied to the signal processing circuit 116 shown in FIG. 2 and FIG. 3 .
- the signal processing circuit 116 shown in FIG. 2 and FIG. 3 remove noise.
- the waveform shaping circuit 117 shapes the waveform, and supplies the signal to the wearable computer 1 via the input/output circuit 101 .
- the optical intensity modulator 124 shown in FIG. 6 cannot extract the intensity modulation signal by differential as shown in FIG. 5 , unlike the polarization modulator 123 shown in FIG. 4 that converts the polarization change of the laser light into the intensity change. Therefore, the optical intensity modulator 124 cannot carry out a differential detection.
- the photodiode 143 directly receives the output from the optical intensity modulator 124 without carrying out a differential detection, noise of the laser light cannot be removed, which results in poor S/N ratio of the reception signal and degradation of communication quality.
- a human hand may hold a set of the transceiver 3 ′ and the wearable computer 1 , as shown in FIG. 9 .
- the transceiver 3 ′ shown in FIG. 9 has such a configuration that the transceiver main body 30 ′ is attached to the bottom of the internal wall surface of the insulating case 33 configured by an insulator, and a battery 6 that drives the transceiver main body 30 ′ is attached on the upper surface of the transceiver main body 30 ′.
- the transmitting and receiving electrode 105 ′ is attached to the bottom of the external wall surface of the insulating case 33 , and this transmitting and receiving electrode 105 ′ is covered with the insulating film 107 ′. Parts other than the operation/input surface of the wearable computer 1 are covered with an insulating case 11 .
- the present invention has been achieved in the light of the above situation, and it is an object of the present invention to provide a technique of normally carrying out transmission and reception operation of a transceiver even if a human body as an electric field transmission medium contacts a wide surface out of an external wall surface of the transceiver, wherein the transceiver includes a transceiver main body that can transmit and receive information via the electric field transmission medium, a battery that drives this transceiver, and an insulating case that covers the transceiver main body.
- the present invention has been made in the light of the above situation, and has an object of suppressing degradation of communication quality of an electric field sensor device using an optical intensity modulator to detect an electric field and a transceiver having this electric field sensor device.
- the present invention has been made in the light of the above situation, and has an object of providing a technique of easily inputting information to a computer and a personal digital assistant each of which is used in a set with a transceiver that can transmit and receive information via an electric field transmission medium.
- a first aspect of the present invention provides a transceiver including: a transmitting and receiving electrode that induces an electric field in an electric field transmission medium, and receives the electric field induced in said electric field transmission medium; a transceiver main body that generates said electric field based on information to be transmitted in said transmitting and receiving electrode, and converts said electric field generated in said transmitting and receiving electrode into reception information, thereby transmitting and receiving information via said electric field transmission medium; a first structure that is interposed between said transmitting and receiving electrode and said electric field transmission medium; a second structure that is interposed between said transceiver main body and said electric field transmission medium; a battery that drives said transceiver main body; and a third structure that is interposed between said transceiver main body and said battery, wherein each of said first, said second, and said third structures is composed of at least one of metal, a semiconductor, and an insulator, and is equivalent as a parallel circuit of a resistor and a capacitor.
- a second aspect of the present invention provides the transceiver according to the first aspect of the invention, wherein the impedance of said second structure and the impedance of said third structure are larger than the impedance of said first structure.
- a third aspect of the present invention provides the transceiver according to the second aspect of the invention, wherein said first structure is an insulating film that covers said transmitting and receiving electrode against said electric field transmission medium.
- a fourth aspect of the present invention provides the transceiver according to the second aspect of the invention, wherein said second structure and said third structure are insulating members.
- a fifth aspect of the present invention provides a transceiver including: a transceiver main body that induces an electric field based on information to be transmitted in an electric field transmission medium from a transmitting electrode, thereby transmitting the information via said electric field transmission medium; a battery that drives said transceiver main body; and an insulating case that incorporates said transceiver main body, wherein said transmitting electrode is provided on the whole surface of a portion of an external wall surface of said insulating case, said electric field transmission medium closely approaching the portion, and is covered with an insulating film so as not to be in direct contact with said electric field transmission medium.
- a sixth aspect of the present invention provides the transceiver according to the fifth aspect of the invention, further including an insulating member between said battery and said transceiver main body.
- a seventh aspect of the present invention provides the transceiver according to the sixth aspect of the invention, wherein the insulating member is a foam member containing air.
- An eighth aspect of the present invention provides the transceiver according to the sixth aspect of the invention, wherein said insulating member is a plurality of wooden pillars.
- a ninth aspect of the present invention provides the transceiver according to the sixth aspect of the invention, wherein said insulating member is a cushion member having predetermined gas confined therein.
- a tenth aspect of the present invention provides the transceiver according to the fifth aspect of the invention, further including a ground electrode that defines a reference voltage which is necessary to drive said transceiver main body, and that is attached to an internal wall surface of said insulating case.
- An eleventh aspect of the present invention provides the transceiver according to the fifth aspect of the invention, further including a ground electrode that defines a reference voltage which is necessary to drive said transceiver main body, and that is attached to an external device at the outside of said insulating case.
- a twelfth aspect of the present invention provides a transceiver including: a transceiver main body that induces an electric field based on information to be transmitted in an electric field transmission medium from a transmitting electrode, and receives information based on the electric field induced in said electric field transmission medium with a receiving electrode, thereby transmitting and receiving the information via said electric field transmission medium; a battery that drives said transceiver main body; and an insulating case that incorporates said transceiver main body, wherein said transmitting electrode is provided on the whole surface of a portion of an external wall surface of said insulating case, said electric field transmission medium closely approaching the portion, and is covered with a first insulating film so as not to be in direct contact with said electric field transmission medium, and said receiving electrode is provided on an external wall surface of said first insulating film, and is covered with a second insulating film so as not to be in direct contact with said electric field transmission medium.
- a thirteenth aspect of the present invention provides a transceiver including: a transceiver main body that induces an electric field based on information to be transmitted in an electric field transmission medium from a transmitting electrode, and receives information based on the electric field induced in said electric field transmission medium with a receiving electrode, thereby transmitting and receiving the information via said electric field transmission medium; a battery that drives said transceiver main body; and an insulating case that incorporates said transceiver main body, wherein said receiving electrode is provided on the whole surface of a portion of an external wall surface of said insulating case, said electric field transmission medium closely approaching the portion, and is covered with a first insulating film so as not to be in direct contact with said electric field transmission medium, and said transmitting electrode is provided on an external wall surface of said first insulating film, and is covered with a second insulating film so as not to be in direct contact with said electric field transmission medium.
- a fourteenth aspect of the present invention provides a transceiver that receives information based on an electric field induced in an electric field transmission medium, thereby receiving information via said electric field transmission medium, said transceiver including: memory means for storing information based on two electric signals and positional information determined according to the electric signal information, by relating these pieces of information to each other; electric field detecting means for detecting an electric field transmitted after being induced in said electric field transmission medium, and converting a change of said electric field into an electric signal; a band pass filter that passes only a signal component having a predetermined band containing said two electric signals out of electric signals obtained by said electric field detecting means; and position conversion processing means for referring to said memory means and obtaining positional information corresponding to the information based on said two electric signals that pass said band pass filter.
- a fifteenth aspect of the present invention provides the transceiver according to the fourteenth aspect of the invention, wherein said memory means stores information based on signal intensity of two electric signals and positional information determined according to the signal intensity information, by relating these pieces of information to each other, said band pass filter includes: a first band pass filter that passes only a signal component having a first band containing one of said electric signals obtained by said electric field detecting means; and a second band pass filter that passes only a signal component having a second band different from said first band containing the other of said electric signals obtained by said electric field detecting means, said transceiver further comprising signal intensity measuring means for measuring signal intensity of a signal component which passes through said first band pass filter and signal intensity of a signal component which passes through said second band pass filter, wherein said position conversion processing means refers to said memory means and obtains positional information corresponding to the information based on signal intensity of the signal component which passes through said first band pass filter and signal intensity of the signal component which passes through said second band pass filter measured by said signal intensity measuring means.
- a sixteenth aspect of the present invention provides the transceiver according to the fifteenth aspect of the invention, wherein said memory means stores information of an intensity difference between electric signals and positional information determined according to the information, by relating these pieces of information to each other, and said position conversion processing means calculates a difference between intensity of the signal component which passes through said first band pass filter and intensity of the signal component which passes through said second band pass filter measured by said signal intensity measuring means, refers to said memory means, and obtains the positional information corresponding to the intensity difference.
- a seventeenth aspect of the present invention provides the transceiver according to the sixteenth aspect of the invention, wherein an external device can rewrite the relation between the information of the intensity difference and the positional information stored in said memory means.
- An eighteenth aspect of the present invention provides the transceiver according to the fifteenth aspect of the invention, wherein said memory means stores information of an intensity ratio between electric signals and positional information determined according to the intensity ratio information, by relating these pieces of information to each other, and said position conversion processing means calculates a ratio of intensity of the signal component which passes through said first band pass filter to intensity of the signal component which passes through said second band pass filter measured by said signal intensity measuring means, refers to said memory means, and obtains the positional information corresponding to the intensity ratio.
- a nineteenth aspect of the present invention provides the transceiver according to the eighteenth aspect of the invention, wherein an external device can rewrite the relation between the information of the intensity ratio and the positional information stored in said memory means.
- a twentieth aspect of the present invention provides the transceiver according to the fourteenth aspect of the invention, wherein said memory means stores information based on a phase difference between two electric signals and positional information determined according to the phase difference information, by relating these pieces of information to each other, said band pass filter includes: a first band pass filter that passes only a signal component having a first band containing one of said electric signals obtained by said electric field detecting means; and a second band pass filter that passes only a signal component having a second band different from said first band containing the other of said electric signals obtained by said electric field detecting means, the transceiver further comprising phase detecting means for detecting a phase of the signal component which passes through said first band pass filter and a phase of the signal component which passes through said second band pass filter, wherein said position conversion processing means calculates a difference between the phase of the signal component which passes through said first band pass filter and the phase of the signal component which passes through said second band pass filter detected by said phase detecting means, refers to said memory means, and obtains the position
- a twenty first aspect of the present invention provides the transceiver according to the twentieth aspect of the invention, wherein an external device can rewrite the relation between the information of the phase difference and the positional information stored in said memory means.
- a twenty second aspect of the present invention provides a positional information obtaining system including: an electric field transmission sheet that transmits an electric charge and has any point thereon contacted by an electric field transmission medium; a first and a second signal generators that are disposed respectively at different positions on said electric field transmission sheet, and induce electric fields based on electric signals having a first band and a second band respectively on said electric field transmission sheet; and a transceiver that receives information based on an electric field induced in said electric field transmission medium, thereby receiving the information via said electric field transmission medium, wherein said transceiver includes: memory means for storing information based on two electric signals and positional information determined according to the electric signal information, by relating these pieces of information to each other; electric field detecting means for detecting an electric field transmitted after being induced in said electric field transmission medium, and converting a change of said electric field into an electric signal; a band pass filter that passes only a signal component having a predetermined band containing said two electric signals out of electric signals obtained by
- a twenty third aspect of the present invention provides an information input system including: an electric field transmission sheet that transmits an electric charge and has any point thereon contacted by an electric field transmission medium; a first and a second signal generators that are disposed respectively at different positions on said electric field transmission sheet, and induce electric fields based on electric signals having a first band and a second band respectively on said electric field transmission sheet; a transceiver that receives information based on an electric field induced in said electric field transmission medium, thereby receiving the information via said electric field transmission medium, said transceiver including: memory means for storing information based on two electric signals and positional information determined according to the electric signal information, by relating these pieces of information to each other; electric field detecting means for detecting an electric field transmitted after being induced in said electric field transmission medium, and converting a change of said electric field into an electric signal; a band pass filter that passes only a signal component having a predetermined band containing said two electric signals out of electric signals obtained by said electric field detecting means;
- a twenty fourth aspect of the present invention provides an information input system including: electric field inducing means that is contacted or operated by an electric field transmission medium, and induces an electric field in said electric field transmission medium according to a physical quantity based on the contact or operation; a transceiver that receives the electric field induced in said electric field transmission medium, applies the electric field to a polarization modulator or an optical intensity modulator, polarization-modulates or optical intensity-modulates laser light according to the electric field, converts the polarization-modulated or optical intensity-modulated laser light into an electric signal, extracts an electric signal having a frequency component concerning a physical quantity based on said contact or operation from the converted electric signals, and outputs the electric signal concerning the physical quantity based on said contact or operation; and information processing means for inputting therein the electric signal concerning the physical quantity based on said contact or operation from said transceiver, and obtains information corresponding to the physical quantity based on said contact or operation by said electric field transmission medium.
- a twenty fifth aspect of the present invention provides an electric field sensor device that modulates optical intensity of laser light based on an electric field to be detected, thereby detecting said electric field, said electric field sensor device having an electric field sensor unit and a light receiving circuit, wherein said electric field sensor unit includes: laser light emitting means; branching means for branching a laser light emitted from said laser light emitting means into a first laser light and a second laser light that are different from each other; and optical intensity modulating means with which said electric field to be detected is coupled, that modulates the optical intensity of said first laser light based on said coupled electric field, and said light receiving circuit includes: first light/voltage converting means for converting the optical intensity of said first laser light modulated by said optical intensity modulating means into a voltage signal; a second light/voltage converting means for converting the optical intensity of said second laser light branched by said branching means into a voltage signal; and differential amplifying means for differentially amplifying the voltage signal obtained by conversion by said first light/
- a twenty sixth aspect of the present invention provides the electric field sensor device according to the twenty fifth aspect of the invention, wherein said electric field sensor unit further includes an optical variable attenuator that attenuates the optical intensity of said second laser light obtained by branching by said branching means, and said second photoelectrical converting means inputs therein said second laser light attenuated by said optical variable attenuator.
- a twenty seventh aspect of the present invention provides the electric field sensor device according to the twenty fifth aspect of the invention, wherein said electric field sensor unit further includes a first optical variable attenuator that attenuates the optical intensity of said first laser light obtained by branching by said branching means at a predetermined rate, and a second optical variable attenuator that attenuates the optical intensity of said second laser light obtained by branching by said branching means at a rate higher than an attenuation rate of said first optical variable attenuator, said optical intensity modulating means inputs therein said first laser light attenuated by said first optical variable attenuator, and said second photoelectrical converting means inputs therein said second laser light attenuated by said second optical variable attenuator.
- a twenty eighth aspect of the present invention provides the electric field sensor device according to the twenty fifth aspect of the invention, wherein said first light/voltage converting means includes: first light/current converting means for converting the optical intensity of said first laser light modulated by said optical intensity modulating means into a current signal; a first voltage source that applies an inverse bias voltage to said first light/current converting means; and a first load resistor that converts said current signal obtained by conversion by said first light/current converting means into a voltage signal, and said second light/voltage converting means includes: second light/current converting means for converting the intensity of said second laser light obtained by branching by said branching means into a current signal; a second voltage source that applies an inverse bias voltage to said second light/current converting means; and a second load resistor that converts said current signal obtained by conversion by said second light/current converting means into a voltage signal.
- a twenty ninth aspect of the present invention provides the electric field sensor device according to the twenty eighth aspect of the invention, wherein at least one of said first load resistor and said second load resistor is a variable resistor.
- a thirtieth aspect of the present invention provides the electric field sensor device according to the twenty eighth aspect of the invention, wherein at least one of said first voltage source and said second voltage source is a variable voltage source.
- a thirty first aspect of the present invention provides the electric field sensor device according to the twenty fifth aspect of the invention, wherein said light receiving circuit further includes amplifying means for amplifying at least one of the voltage signal obtained by conversion by said first light/voltage converting means and the voltage signal obtained by conversion by said second light/voltage converting means.
- a thirty second aspect of the present invention provides a transceiver that receives information based on an electric field induced in an electric field transmission medium, thereby receiving the information via said electric field transmission medium, said transceiver including: said electric field sensor device according to the twenty fifth aspect; a signal processing circuit that at least removes a noise from a voltage signal output from said electric field sensor device; noise detecting means for detecting quantity of a noise component of the voltage signal output from said signal processing circuit; and a control signal generator that generates a control signal to variably control a variable value of said electric field sensor unit or said light receiving circuit based on the detection data output from said noise detecting means.
- FIG. 1 is an image diagram of carrying out communications between plural wearable computers via a human body.
- FIG. 2 is an overall configuration diagram of a conventional transceiver main body.
- FIG. 3 is an overall configuration diagram of another conventional transceiver main body.
- FIG. 4 is a detailed configuration diagram of an electric field sensor unit and a light receiving circuit of a conventional (polarization modulation type) transceiver main body.
- FIG. 5 is a diagram showing a waveform of an input signal of a differential amplifier shown in FIG. 4 .
- FIG. 6 is a detailed configuration diagram of an electric field sensor unit and a light receiving circuit of a conventional (optical intensity modulation type) transceiver main body.
- FIG. 7 is a principle diagram when an optical intensity modulator used in the electric field sensor unit of the conventional (optical intensity modulation type) transceiver main body is an electroabsorption type.
- FIG. 8 is a principle diagram when the optical intensity modulator used in the electric field sensor unit of the conventional (optical intensity modulation type) transceiver main body is a Mach-Zehnder.
- FIG. 9 is an image diagram showing a using state of a combination of a transceiver and a wearable computer that are held in a human hand.
- FIG. 10 is an image diagram of a front view showing a using state of a transceiver and a wearable computer according to a first embodiment of the present invention.
- FIG. 11 is an image diagram of a top plan view showing a using state of the transceiver and the wearable computer according to the first embodiment of the present invention.
- FIG. 12 is a diagram showing frequency bands for information communication, a signal generator A, and a signal generator B, respectively.
- FIG. 13 is an overall configuration diagram of a transceiver main body within the transceiver according to the first embodiment.
- FIG. 14 is an overall configuration diagram of a transceiver main body within a transceiver according to a second embodiment.
- FIG. 15 is a diagram showing a concrete example of an electric field transmission sheet according to the first and the second embodiments.
- FIG. 16 is a diagram showing a concrete example of the electric field transmission sheet according to the first and the second embodiments.
- FIG. 17 is a diagram showing a concrete example of the electric field transmission sheet according to the first and the second embodiments.
- FIG. 18 is an overall configuration diagram of a transceiver main body according to third to seventh embodiments of the present invention.
- FIG. 19 is a detailed configuration diagram of an electric field sensor unit and a light receiving circuit of a transceiver main body according to the third embodiment.
- FIG. 20 is a detailed configuration diagram of an electric field sensor unit and a light receiving circuit of a transceiver main body according to the fourth embodiment.
- FIG. 21 is a detailed configuration diagram of an electric field sensor unit and a light receiving circuit of a transceiver main body according to the fifth embodiment.
- FIG. 22 is a detailed configuration diagram of an electric field sensor unit and a light receiving circuit of a transceiver main body according to the sixth embodiment.
- FIG. 23 is a detailed configuration diagram of an electric field sensor unit and a light receiving circuit of a transceiver main body according to the seventh embodiment.
- FIG. 24 is an overall configuration diagram of a transceiver main body according to an eighth embodiment of the present invention.
- FIG. 25 is a diagram showing an equivalent circuit between a human body, a transmitting and receiving electrode, and a transceiver main body.
- FIG. 26 is a diagram showing an equivalent circuit between a human body, a transceiver main body, and a battery.
- FIG. 27 is an overall configuration diagram of a transceiver and a wearable computer according to a ninth embodiment of the present invention.
- FIG. 28 is a functional block diagram showing mainly a function of the transceiver main body.
- FIG. 29 is a detailed configuration diagram of an electric field sensor device.
- FIG. 30 is an image diagram showing a using state of the transceiver and the wearable computer shown in FIG. 27 .
- FIG. 31 is an overall configuration diagram of a transceiver and a wearable computer according to a tenth embodiment of the present invention.
- FIG. 32 is an overall configuration diagram of a transceiver and a wearable computer according to an eleventh embodiment of the present invention.
- FIG. 33 is an overall configuration diagram of a transceiver and a wearable computer according to a twelfth embodiment of the present invention.
- FIG. 34 is an overall configuration diagram of a transceiver and a wearable computer according to a thirteenth embodiment of the present invention.
- FIG. 35 is an overall configuration diagram of a transceiver and a wearable computer according to a fourteenth embodiment of the present invention.
- FIG. 36 is a diagram showing other embodiment of the present invention.
- FIG. 37 is a diagram showing other embodiment of the present invention.
- a transceiver 3 induces an electric field based on information to be transmitted in an electric field transmission medium (such as the human body 100 ), and receives information based on an electric field induced in the electric field transmission medium, thereby transmitting and receiving information via the electric field transmission medium.
- an electric field transmission medium such as the human body 100
- FIG. 10 is an image diagram of a front view showing a using state of the transceiver 3 and the wearable computer 1 according to the first embodiment.
- FIG. 11 is an image diagram of a top plan view showing the using state.
- an insulating sheet 301 is adhered to a flat surface of a table 300 , and an electric field transmission sheet 302 that can transmit an electric field is adhered to a flat surface of the insulating sheet 301 .
- Signal generators A and B are disposed at different comers on the flat surface of the electric field transmission sheet 302 .
- FIG. 11 when the electric field transmission sheet 302 is rectangular, these signal generators are disposed at different optional comers.
- Each of the signal generators A and B has a configuration similar to that including the transmitter 103 , the transmitting electrode 105 ′ a, and the insulating film 107 ′ a as shown in FIG. 3 , and can induce an electric field based on an electric signal concerning transmission frequencies fa and fb respectively on the electric field transmission sheet 302 as shown in FIG. 12 .
- FIG. 13 is an overall configuration diagram of a transceiver main body 30 a within the transceiver 3 according to the present embodiment.
- the transceiver main body 30 a is similar to the conventional transceiver main body 30 ′ in that the transceiver main body 30 a has the I/O (input/output) circuit 101 , the transmitter 103 , the transmitting electrode 105 a , the insulating films 107 a and 107 b , the receiving electrode 105 b , the electric field sensor device 115 , the signal processing circuit 116 , and the waveform shaping circuit 117 .
- the transceiver main body 30 a according to the present embodiment further has band pass filters 11 a and 11 b, signal intensity measuring units 13 a and 13 b , a position conversion processor 15 , and a memory 17 .
- the I/O circuit 101 is used for the transceiver main body 30 a to input and output information (data) to and from an external device such as the wearable computer 1 .
- the transmitter 103 consists of a transmitter circuit that induces, based on the information (data) output from the I/O circuit 101 , an electric field concerning this information in the human body 100 .
- the transmitting electrode 105 a is used for the transmitter 103 to induce an electric field in the human body 100 , and is used as a transmitting antenna.
- the insulating film 107 a is an insulator film disposed between the transmitting electrode 105 a and the human body 100 , and prevents the transmitting electrode 105 a from directly contacting the human body 100 .
- the receiving electrode 105 b is used to receive an electric field transmitted after being induced in the human body 100 from the wearable computer 1 and the transceiver 3 ′ that are mounted on other part of the human body 100 and the PC 5 and the transceivers 3 ′ a and 3 ′ b, and is used as a receiving antenna.
- the insulating film 107 b is an insulator film disposed between the receiving electrode 105 b and the human body 100 , like the insulating film 107 a.
- the electric field sensor device 115 has a function of detecting an electric field received by the receiving electrode 105 b , and converting this electric field into an electric signal as reception information.
- the signal processing circuit 116 consists of an amplifier 114 that amplifies an electric signal transmitted from the electric field sensor device 115 , and a band pass filter 151 .
- This band pass filter 151 is a filter circuit having a characteristic of limiting the band of an electric signal output from the amplifier 114 and removes unnecessary noise and an unnecessary signal component, thereby passing a signal component of only a frequency band of a constant width (f 1 to f 2 ) for information communication as shown in FIG. 12 out of the electric signals output from the amplifier 114 .
- the waveform shaping circuit 117 shapes the waveform (signal processing) of an electric signal transmitted from the signal processing circuit 116 , and supplies the processed electric signal to the wearable computer 1 via the I/O circuit 101 .
- the band pass filter 11 a is a filter circuit having a characteristic of limiting the band of an electric signal output from the amplifier 114 and removes unnecessary noise and an unnecessary signal component, thereby passing a signal component of only a frequency band (fa) for the signal generator A as shown in FIG. 12 out of the electric signals output from the amplifier 114 .
- the signal intensity measuring unit 13 a is a circuit that measures signal intensity of an electric signal concerning the signal component that is passed by the band pass filter 11 a.
- the band pass filter 11 b is a filter circuit having a characteristic of limiting the band of an electric signal output from the amplifier 114 and removes unnecessary noise and an unnecessary signal component, thereby passing a signal component of only a frequency band (fb) for the signal generator B as shown in FIG. 12 out of the electric signals output from the amplifier 114 .
- the signal intensity measuring unit 13 b is a circuit that measures signal intensity of an electric signal concerning the signal component that is passed by the band pass filter 11 b.
- the memory 17 stores an intensity difference between two electric signals and a specific position in a two-dimensional space by relating these pieces of information to each other.
- an optional position on the electric field transmission sheet 302 shown in FIG. 10 and FIG. 11 and the intensity difference are related to each other in advance.
- An external device such as the wearable computer 1 can rewrite the relationship between the intensity difference and the specific position stored in the memory 17 , via the I/O circuit 101 .
- the position conversion processor 15 is a CPU (central processing unit) or the like that calculates a difference between the signal intensity measured by the signal intensity measuring unit 13 a and the signal intensity measured by the signal intensity measuring unit 13 b , and collates this intensity difference with the intensity difference stored in the memory 17 , thereby converting the calculated intensity difference into a specific position in a two-dimensional space.
- the receiving electrode 105 b receives electric fields from the signal generators A and B via the finger (human body 100 ) and the insulating film 107 b .
- the electric field sensor device 115 couples (applies) the received electric fields to an electro-optic crystal, not shown, of the electric field sensor device 115 , converts the electric fields into electric signals, and transmits the electric signals to the signal processing circuit 116 .
- the amplifier 114 of the signal processing circuit 116 amplifies the electric signals, and transmits the amplified electric signals to the band pass filter 151 . However, the electric signals concerning the electric fields from the signal generators A and B do not pass through the band pass filter 116 .
- the electric signals transmitted from the amplifier 114 are also transmitted to the band pass filters 11 a and 11 b.
- the band pass filter 11 a passes the signal component of only the band (fa) for the signal generator A out of the electric signals concerning the electric fields from the signal generators A and B, and transmits this signal component to the signal intensity measuring unit 13 a .
- the signal intensity measuring unit 13 a measures signal intensity of the electric signal concerning the signal component that is passed by the band pass filter 11 a.
- the band pass filter 11 b passes the signal component of only the band (fb) for the signal generator B out of the electric signals concerning the electric fields from the signal generators A and B, and transmits this signal component to the signal intensity measuring unit 13 b .
- the signal intensity measuring unit 13 b measures signal intensity of the electric signal concerning the signal component that is passed by the band pass filter 11 b.
- the position conversion processor 15 calculates an intensity difference between the signal intensity measured by the signal intensity measuring unit 13 a and the signal intensity measured by the signal intensity measuring unit 13 b , and collates this intensity difference with the intensity difference stored in the memory 17 , thereby converting the calculated intensity difference into the specific position ⁇ in the two-dimensional space on the electric field transmission sheet 202 .
- the position conversion processor 15 transmits the position information (data) at the specific position ⁇ obtained by the position conversion processor 15 to the wearable computer 1 via the I/O circuit 101 .
- the intensity difference between the signal intensity measured by the signal intensity measuring unit 13 a and the signal intensity measured by the signal intensity measuring unit 13 b is calculated.
- This intensity difference is collated with the intensity difference stored in the memory 17 , thereby converting the calculated intensity difference into the specific position in the two-dimensional space.
- the position conversion processor 15 calculates the intensity difference between the signal intensity measured by the signal intensity measuring unit 13 a and the signal intensity measured by the signal intensity measuring unit 13 b .
- the position conversion processor 15 may also calculate an intensity ratio of the signal intensity measured by the signal intensity measuring unit 13 a to the signal intensity measured by the signal intensity measuring unit 13 b .
- the memory 17 needs to store the intensity ratio between the two electric signals and the specific position in the two-dimensional space by relating these pieces of information to each other.
- FIG. 14 is an overall configuration diagram of a transceiver main body 30 b within a transceiver according to the second embodiment. Constituent parts that are identical with those according to the first embodiment are assigned with same reference numerals, and their explanation is omitted.
- a phase detector 23 a shown in FIG. 14 is a circuit that detects a phase of an electric signal concerning a signal component which is passed by the band pass filter 11 a.
- a phase detector 23 b is a circuit that detects a phase of an electric signal concerning a signal component which is passed by the band pass filter 11 b.
- a memory 27 stores a phase difference between two electric signals and a specific position in a two-dimensional space by relating these pieces of information to each other.
- an optional position on the electric field transmission sheet 302 shown in FIG. 10 and FIG. 11 and the phase difference are related to each other in advance.
- An external device such as the wearable computer 1 can rewrite the relationship between the phase difference and the specific position stored in the memory 27 , via the I/O circuit 101 .
- a position conversion processor 25 is a CPU or the like that calculates a difference between the phase measured by the phase detector 23 a and the phase measured by the phase detector 23 b , and collates this phase difference with the phase difference stored in the memory 27 , thereby converting the calculated phase difference into a specific position in a two-dimensional space.
- the receiving electrode 105 b receives electric fields from the signal generators A and B via the finger (human body 100 ) and the insulating film 107 b .
- the electric field sensor device 115 couples (applies) the received electric fields to an electro-optic crystal, not shown, of the electric field sensor device 115 , converts the electric fields into electric signals, and transmits the electric signals to the signal processing circuit 116 .
- the amplifier 114 of the signal processing circuit 116 amplifies the electric signals, and transmits the amplified electric signals to the band pass filter 151 .
- the electric signals concerning the electric fields from the signal generators A and B do not pass through the band pass filter 151 .
- the electric signals transmitted from the amplifier 114 are also transmitted to the band pass filters 11 a and 11 b.
- the band pass filter 11 a passes the signal component of only the band (fa) for the signal generator A out of the electric signals concerning the electric fields from the signal generators A and B, and transmits this signal component to the phase detector 23 a .
- the phase detector 23 a detects a phase of the electric signal concerning the signal component that is passed by the band pass filter 11 a.
- the band pass filter 11 b passes the signal component of only the band (fb) for the signal generator B out of the electric signals concerning the electric fields from the signal generators A and B, and transmits this signal component to the phase detector 23 b .
- the phase detector 23 b detects a phase of the electric signal concerning the signal component that is passed by the band pass filter 11 b.
- the position conversion processor 25 calculates a phase difference between the phase measured by the phase detector 23 a and the phase measured by the phase detector 23 b , and collates this phase difference with the phase difference stored in the memory 27 , thereby converting the calculated phase difference into the specific position ox in the two-dimensional space on the electric field transmission sheet 302 .
- the position conversion processor 25 transmits the position information (data) at the specific position ⁇ obtained by the position conversion processor 25 to the wearable computer 1 via the I/O circuit 101 .
- FIG. 15 and FIG. 16 show an example that the above embodiments are applied to an electric field transmission sheet 302 a and a keyboard of a personal computer. As shown in FIG. 15 , a picture of a keyboard is printed on the electric field transmission sheet 302 a . When a person touches a specific position ⁇ 1 , it is possible to specify the touched key based on respective distances x 1 and y 1 from the signal generators A and B.
- positional information that is, the distances x 1 and y 1 from the signal generators A and B respectively in this case, is transmitted from the transceiver 3 to the wearable computer 1 .
- the wearable computer 1 has a table showing a relationship between the positional information and the input information that is the same as the relationship between the position on the electric field transmission sheet 302 a and the print information at this position. As a result, the wearable computer 1 can understand the information that the person intends to indicate.
- FIG. 17 shows an example that the above embodiments are applied to an electric field transmission sheet 302 b such as a touch panel, a touch screen, and a showcase.
- an electric field transmission sheet 302 b such as a touch panel, a touch screen, and a showcase.
- two signal generators and “an electric field transmission sheet” are used.
- a person touches the electric field transmission sheet with a hand (finger) electric signals from the two signal generators are transmitted to a transceiver via the hand (human body 100 ).
- the transceiver separates the two electric signals, and obtains information about distances from the two signal generators to the touched position, based on the two electric signals.
- the gist of the present invention is not limited to this.
- the present invention can be applied not only to a two-dimensional plane surface but also to a three-dimensional space.
- the three signal generators can transmit signals to a finger that indicates a certain three-dimensional point via the electric field transmission medium.
- the transceiver can separate the three signals.
- the transceiver obtains positional information of the point indicated by the person within a three-dimensional space. This information is transmitted to an information device such as a wearable computer.
- an information device such as a wearable computer.
- the intended information can be input to the information device.
- the transceiver When the transceiver has a sufficient processing speed, the transceiver can understand the information of the position of a finger as information about the move of the finger. In other words, for example, when the electric field transmission sheet is touched with the finger, the transceiver can understand the move of the finger in real time.
- this information is transmitted to an information device such as a wearable computer, the move information itself or information relevant to the move information intended by a person can be input to the information device.
- the information transmitted to the transceiver via the human body is not limited to a signal based on which a position (speed) can be obtained.
- the pressure signal can be also converted into an electric field, and can be transmitted to the transceiver via a finger or the like.
- the transceiver can obtain the information of pressing force that a person intends.
- this information is transmitted to an information device such as a wearable computer, the information device can obtain information corresponding to the pressing force.
- the transceiver itself may have this information. With this arrangement, the transceiver itself can obtain information intended by a person.
- a third device other than the information device such as a wearable computer and the transceiver can have this information, and the information device and the transceiver can obtain the information from this third device.
- An electric field sensor device 115 a , and an optical intensity modulation transceiver (hereinafter simply referred to as a “transceiver”) 3 having the electric field sensor device 115 a according to a third embodiment of the present invention are explained with reference to FIG. 18 and FIG. 19 .
- FIG. 18 is an overall configuration diagram of a transceiver main body 30 c that is used to carry out data communications via the human body 100 .
- FIG. 18 is an overall configuration diagram common to the third to seventh embodiments.
- the transceiver main body 30 c has the I/O (input/output) circuit 101 , the transmitter 103 , the transmitting electrode 105 a , the receiving electrode 105 b , the insulating films 107 a and 107 b , the electric field sensor device 115 (the electric field sensor unit 110 , and a light receiving circuit 152 ), the signal processing circuit 116 , and the waveform shaping circuit 117 .
- the I/O circuit 101 is used for the transceiver main body 3 c to input and output information (data) to and from an external device such as the wearable computer 1 .
- the transmitter 103 consists of a transmitter circuit that induces, based on the information (data) output from the I/O circuit 101 , an electric field concerning this information in the human body 100 .
- the transmitting electrode 105 a is used for the transmitter 103 to induce an electric field in the human body 100 , and is used as a transmitting antenna.
- the receiving electrode 105 b is used to receive an electric field transmitted after being induced in the human body 100 from the wearable computer 1 and the transceiver 3 ′ that are mounted on other part of the human body 100 and the PC 5 and the transceivers 3 ′ a and 3 ′ b, and is used as a receiving antenna.
- the insulating film 107 a is an insulator film disposed between the transmitting electrode 105 a and the human body 100 , and prevents the transmitting electrode 105 a from directly contacting the human body 100 .
- the insulating film 107 b is an insulator film disposed between the receiving electrode 105 b and the human body 100 , and prevents the receiving electrode 105 b from directly contacting the human body 100 .
- the electric field sensor unit 110 that constitutes the electric field sensor device 115 has a function of applying an electric field received by the receiving electrode 105 b to the laser light, thereby changing the optical intensity of the laser light.
- the light receiving circuit 152 that constitutes the electric field sensor device 115 has a function of receiving the laser light of which optical intensity is changed, converting the laser light into an electric signal, and performing signal processing such as amplification of this electric signal.
- the signal processing circuit 116 consists of at least a band pass filter. This band pass filter removes a frequency component other than a frequency component concerning reception information as an electric field to be detected among electric signals having various frequencies (that is, takes out only the frequency component concerning the reception information), thereby performing signal processing such as removal of noise from the electric signal.
- the waveform shaping circuit 117 shapes the waveform (signal processing) of an electric signal transmitted from the signal processing circuit 116 , and supplies the processed electric signal to the wearable computer 1 via the I/O circuit 101 .
- the electric field sensor device 115 a according to the third embodiment as one example of the electric field sensor device 115 is explained in detail with reference to FIG. 19 .
- the electric field sensor device 115 a according to the present embodiment has an electric field sensor unit 110 a as one example of the electric field sensor unit 110 , and a light receiving circuit 152 a as one example of the light receiving circuit 152 .
- the electric field sensor device 115 a is provided in the transceiver main body 30 c as one example of the transceiver main body 30 .
- the electric field sensor unit 110 a consists of the current source 119 , the laser diode 121 , the lens 133 , a beam splitter 139 , the optical intensity modulator 124 , and the first and the second lenses 141 a and 141 b.
- the optical intensity modulator 124 is configured to change the optical intensity of light that passes depending on the electric field intensity to be coupled.
- the first electrode 125 and the second electrode 127 are provided on both side surfaces of the optical intensity modulator 124 , that are opposite in a vertical direction in the drawing.
- the first electrode 125 and the second electrode 127 sandwich from both sides the proceeding direction of the laser light from the laser diode 121 within the optical intensity modulator 124 , and can couple the electric field with the laser light at a right angle.
- the electric field sensor unit 110 a is connected to the receiving electrode 105 b via the first electrode 125 .
- the second electrode 127 that is opposite to the first electrode 125 is connected to a ground electrode 131 , and functions as a ground electrode to the first electrode 125 .
- the receiving electrode 105 b detects an electric field that is transmitted after being induced in the human body 100 , transmits this electric field to the first electrode 125 , and can couple the electric field with the optical intensity modulator 124 via the first electrode 125 .
- the laser light that is output from the laser diode 121 based on the current control by the current source 119 is made parallel light via the lens 133 .
- the parallel laser light is incident to the beam splitter 139 .
- the beam splitter 139 is an optical system that branches the incident laser light into two laser lights and outputs the branched lights.
- a first laser light obtained by the branching by the beam splitter 139 is incident to the first lens 141 a via the optical intensity modulator 124 .
- a second laser light obtained by the branching by the beam splitter 139 is incident to the second lens 141 b not via the optical intensity modulator 124 .
- the light receiving circuit 152 a has a first set including the first photodiode 143 a that converts the first laser light into a current signal according to the optical intensity of the first laser light of which optical intensity is modulated by the optical intensity modulator 124 , the first constant voltage source 147 a that applies an inverse bias voltage to the first photodiode 143 a , and the first load resistor 145 a that converts the current signal obtained by conversion by the first photodiode 143 a into a voltage signal, and a second set including the second photodiode 143 b that converts the second laser light into a current signal according to the optical intensity of the second laser light received via the second lens 141 b, the second constant voltage source 147 b that applies an inverse bias voltage to the second photodiode 143 b , and the second load resistor 145 b that converts the current signal obtained by conversion by the second photodiode 143 b into a voltage signal.
- the first photodiode 143 a receives the first laser light that passes through the optical intensity modulator 124 and the first lens 141 a of the electric field sensor unit 110 a, and the first set outputs a voltage signal (including a signal component) as a result.
- the second photodiode 143 b receives the second laser light that passes through the second lens 141 b of the electric field sensor unit 110 a, and the second set outputs a voltage signal (not including a signal component) containing noise of the laser light as a result.
- the light receiving circuit 152 a also has the differential amplifier 112 that differentially amplifies a voltage signal obtained by conversion by the first load resistor 145 a and a voltage signal obtained by conversion by the second load resistor 145 b .
- the differential amplifier 112 differentially amplifies the voltage signals, and supplies the output to the signal processing circuit 116 shown in FIG. 18 .
- laser light is branched immediately before the laser light is incident to the optical intensity modulator 124 .
- One laser light is input to the optical intensity modulator 124 , and is used as laser light (including a signal component) for detecting an electric field.
- the other laser light is not input to the optical intensity modulator 124 , and is used as laser light (not including a signal component) for only removing noise from the laser light. Therefore, it is possible to remove noise from the laser light even when the optical intensity modulator 124 is used that cannot differentially take out an intensity modulation signal unlike the polarization modulator 123 that converts a polarization change of the laser light into an intensity change.
- An electric field sensor device 115 b , and the optical intensity modulation transceiver 3 having the electric field sensor device 115 b according to a fourth embodiment of the present invention are explained with reference to FIG. 20 .
- the electric field sensor device 115 b has the following electric field sensor unit 110 b in place of the electric field sensor unit 110 a of the electric field sensor device 115 a according to the third embodiment. Constituent parts of the electric field sensor unit 110 b that are identical with those of the electric field sensor unit 110 a are assigned with the same reference numerals, and their explanation is omitted. Since the light receiving circuit 152 a according to the present embodiment has the same configuration as that of the light receiving circuit 152 a according to the first embodiment, explanation of the light receiving circuit 152 a is omitted.
- the electric field sensor unit 110 b has a first optical variable attenuator 134 A inserted between the beam splitter 139 and the optical intensity modulator 124 , and has a second optical variable attenuator 134 B inserted between the beam splitter 139 and the second lens 141 b .
- the first and the second optical variable attenuators 134 A and 134 B attenuate the optical intensity of laser light by a predetermined rate.
- the first laser light passes through the optical intensity modulator 124 , but the second laser light does not pass through the optical intensity modulator 124 . Since transmission efficiency of the second laser light is higher than that of the first laser light, both transmission efficiencies need to be balanced. According to the present embodiment, attenuation of the second optical variable attenuator 134 B through which the second laser light passes is set larger than attenuation of the first optical variable attenuator 134 A through which the first laser light passes.
- the first optical variable attenuator 134 A attenuates the optical intensity of the first laser light obtained by branching by the beam splitter 139 , and then the first photodiode 143 a converts the first laser light into a current signal.
- the second optical variable attenuator 134 B attenuates the optical intensity of the second laser light obtained by branching by the beam splitter 139 , and then the second photodiode 143 b converts the second laser light into a current signal.
- the attenuation of the laser light that passes through the first optical variable attenuator 134 B is larger than the attenuation of the laser light that passes through the second optical variable attenuator 134 A.
- noise is removed from the laser light, by inserting the first and the second optical variable attenuators 134 A and 134 B. Therefore, input signals to the differential amplifier 112 can be balanced even when the laser light is branched.
- the first optical variable attenuator 134 A can be omitted.
- An electric field sensor device 115 c , and the optical intensity modulation transceiver 3 having the electric field sensor device 115 c according to a fifth embodiment of the present invention are explained with reference to FIG. 21 .
- the electric field sensor device 115 c has the following light receiving circuit 152 b in place of the light receiving circuit 152 a of the electric field sensor device 115 a according to the third embodiment. Constituent parts of the light receiving circuit 152 b that are identical with those of the light receiving circuit 152 a are assigned with the same reference numerals, and their explanation is omitted. Since the electric field sensor unit 110 a according to the present embodiment has the same configuration as that of the electric field sensor unit 110 a according to the first embodiment, explanation of the electric field sensor unit 110 a is omitted.
- the light receiving circuit 152 b in place of the first and the second load resistors 145 a and 145 b according to the third embodiment, has first and second variable load resistors 145 A and 145 B respectively.
- the first and the second variable load resistors 145 A and 145 B have variable load resistances, and the resistance of the second variable load resistor 145 B is set larger than that of the first variable load resistor 145 A.
- voltage signals that are output from the first photodiode 143 a and the second photodiode 143 b can have the same signal intensity.
- the light receiving circuit 152 b has the first and the second variable load resistors 145 A and 145 B respectively, thereby removing noise from the laser light. Therefore, input signals to the differential amplifier 112 can be balanced even when the laser light is branched.
- variable load resistors 145 A and 145 B When input signals to the differential amplifier 112 can be balanced using only one of the first and the second variable load resistors 145 A and 145 B, one of these variable load resistors can be omitted.
- An electric field sensor device 115 d , and the optical intensity modulation transceiver 3 having the electric field sensor device 115 d according to a sixth embodiment of the present invention are explained with reference to FIG. 22 .
- the electric field sensor device 115 d has the following light receiving circuit 152 c in place of the light receiving circuit 152 a of the electric field sensor device 115 a according to the third embodiment. Constituent parts of the light receiving circuit 152 c that are identical with those of the light receiving circuit 152 a are assigned with the same reference numerals, and their explanation is omitted. Since the electric field sensor unit 110 a according to the present embodiment has the same configuration as that of the electric field sensor unit 110 a according to the first embodiment, explanation of the electric field sensor unit 110 a is omitted.
- the light receiving circuit 152 c in place of the first and the second constant voltage sources 147 a and 147 b according to the third embodiment, has first and second variable voltage sources 147 A and 147 B respectively.
- the first and the second variable voltage sources 147 A and 147 B have variable voltages, and the voltage of the second variable voltage source 147 B is set smaller than that of the first variable voltage source 147 A.
- voltage signals that are output from the first photodiode 143 a and the second photodiode 143 b can have the same signal intensity.
- the light receiving circuit 152 c has the first and second variable voltage sources 147 A and 147 B respectively, thereby removing noise from the laser light. Therefore, input signals to the differential amplifier 112 can be balanced even when the laser light is branched.
- variable voltage sources 147 A and 147 B When input signals to the differential amplifier 112 can be balanced using only one of the first and the second variable voltage sources 147 A and 147 B, one of these variable voltage sources can be omitted.
- An electric field sensor device 115 e , and the optical intensity modulation transceiver 3 having the electric field sensor device 115 e according to a seventh embodiment of the present invention are explained with reference to FIG. 23 .
- the electric field sensor device 115 e has the following light receiving circuit 152 d in place of the light receiving circuit 152 a of the electric field sensor device 115 a according to the third embodiment. Constituent parts of the light receiving circuit 152 d that are identical with those of the light receiving circuit 152 a are assigned with the same reference numerals, and their explanation is omitted. Since the electric field sensor unit 110 a according to the present embodiment has the same configuration as that of the electric field sensor unit 110 a according to the first embodiment, explanation of the electric field sensor unit 110 a is omitted.
- a first and a second variable gain amplifiers 149 A and 149 B that amplify voltage signals output from the first and the second photodiodes 143 a and 143 b respectively before these voltage signals are input to the differential amplifier 112 .
- the first and the second variable gain amplifiers 149 A and 149 B have variable voltage gains, and the voltage gain of the second variable gain amplifier 149 B is set smaller than that of the first variable gain amplifier 149 A.
- voltage signals that are output from the first photodiode 143 a and the second photodiode 143 b can have the same signal intensity.
- the first and the second variable gain amplifiers 149 A and 149 B that amplify voltage signals output from the first and the second photodiodes 143 a and 143 b respectively before these voltage signals are input to the differential amplifier 112 , thereby removing noise from the laser light. Therefore, input signals to the differential amplifier 112 can be balanced even when the laser light is branched.
- variable gain amplifiers 149 A and 149 B When input signals to the differential amplifier 112 can be balanced using only one of the first and the second variable gain amplifiers 149 A and 149 B, one of these variable gain amplifiers can be omitted.
- an electroabsorption (EA) optical intensity modulator for the optical intensity modulators according to the third to the seventh embodiments, an electroabsorption (EA) optical intensity modulator, a Mach-Zehnder optical intensity modulator, and the like can be employed as in the conventional practice.
- EA electroabsorption
- a transceiver main body 30 d of a transceiver according to an eighth embodiment of the present invention is explained with reference to FIG. 24 .
- the transceiver main body 30 d has an overall configuration as shown in FIG. 24 .
- the transceiver main body 30 d excluding an electric field sensor device 215 , a noise detector 218 , and a control signal generator 219 has the same configuration as that of the transceiver main body 30 c according to the third embodiment, and therefore, identical parts are assigned with the same reference numerals and their explanation is omitted.
- the transceiver main body 30 d uses any one of the electric field sensor devices 115 b to 115 e according to the fourth to the seventh embodiments, for the electric field sensor device 215 .
- the transceiver main body 30 d includes the noise detector 218 that detects a magnitude of noise of a voltage signal output from the signal processing circuit 116 , and the control signal generator 219 that generates a control signal to variably control variable values of the electric field sensor unit 110 and the light receiving circuit 152 that constitute the electric field sensor device 215 , based on detection data output from the noise detector 218 .
- the noise detector 218 detects a level of noise that remains in the electric signal output from the signal processing circuit 116 , that is, a level of noise that is present in a frequency band concerning reception information as an electric field to be detected.
- variable value means the following in respective embodiments.
- the variable value means attenuation of the optical intensity of the first and the second optical variable attenuators 134 A and 134 B.
- the variable value means resistance of the first and the second variable load resistors 145 A and 145 B.
- the variable value means a voltage of the first and the second variable voltage sources 147 A and 147 B.
- the variable value means a voltage gain of the first and the second variable gain amplifiers 113 A and 113 B.
- the transceiver including a transceiver main body that can transmit and receive information via an electric field transmission medium, a battery that drives the transceiver main body, and an insulating case that covers the transceiver main body, and the transceiver being of a type that a human body (hand) as the electric field transmission medium contacts a wide surface of an external wall surface.
- the main point of the embodiment of the transceiver is explained first. Regarding the transceiver and the wearable computer shown in FIG. 9 , the equivalent circuit between the human body (hand), the transmitting and receiving electrode, the transceiver main body, and the battery is considered.
- FIG. 25 is a diagram showing an equivalent circuit between a human body, a transmitting and receiving electrode, and a transceiver main body.
- the human body 100 and the transmitting and receiving electrode 105 ′ are separated by the insulating film 107 ′. Therefore, impedance between the human body 100 and the transmitting and receiving electrode 105 can be expressed by the equivalent circuit as shown in FIG. 25 .
- an induced alternate current electric field (frequency f) to the human body 100 needs to be large.
- the impedance between the human body 100 and the transmitting and receiving electrode 105 needs to be small.
- a resistance component of the impedance between the human body 100 and the transmitting and receiving electrode 105 is considered very large. Therefore, in order to make the impedance small, the capacitance component needs to be set large.
- the insulating film 107 is too thin, there is a high possibility that the human body 100 directly touches the transmitting and receiving electrode 105 , and a risk that a large current flows to the human body 100 increases. Therefore, when the area of the transmitting and receiving electrode 105 is increased, the capacitance can be increased while securing safety, which is preferable. When the transmitting and receiving electrode 105 is made large, a shielding effect can be expected.
- FIG. 26 is a diagram showing an equivalent circuit between a human body, a transceiver main body, and a battery.
- an insulator When an insulator is interposed between the items, and in order to increase this effect, it is necessary to use an insulator having a small dielectric constant, or decrease an area of contact between the insulator, the human body 100 , the transceiver main body 30 , and the battery 6 , or increase the thickness of the insulator.
- the following embodiment is considered to carry out secure and highly reliable communications via the human body in the transceiver shown in FIG. 9 .
- a ninth embodiment is explained below with reference to FIG. 27 to FIG. 30 .
- FIG. 27 is an overall configuration diagram of a transceiver 3 a and the wearable computer 1 according to a ninth embodiment of the present invention.
- FIG. 28 is a functional block diagram showing mainly a function of the transceiver main body 30 .
- FIG. 29 is a detailed configuration diagram of an electric field sensor device 115 ′.
- FIG. 30 is an image diagram showing a using state of the transceiver 3 a and the wearable computer 1 shown in FIG. 27 .
- the transceiver 3 a consists of the insulating case 33 formed with an insulator, a device incorporated in the insulating case 33 , and the following members attached to the outside of the insulating case 33 .
- An insulating foam member 7 a that weakens electric coupling between the insulating case 33 and the transceiver main body 30 is attached to the bottom of the internal wall surface of the insulating case 33 .
- the transceiver main body 30 that carries out transmission and reception of data (information) to and from the wearable computer 1 is attached to the upper surface of the insulating foam member 7 a .
- An insulating foam member 7 b that weakens electric coupling between the transceiver main body 30 and the battery 6 is attached to the upper surface of the transceiver main body 30 .
- the battery 6 that drives the transceiver 30 is attached to the upper surface of the insulating foam member 7 b .
- the insulating foam member 7 a is sandwiched (supported in a sandwiched state) between the insulating case 33 and the transceiver main body 30
- the insulating foam member 7 b is sandwiched between the transceiver main body 30 and the battery 6 .
- the insulating foam members 7 a and 7 b are formed with numerous holes containing air. Therefore, the insulating foam member 7 a can restrict transmission of noise between the insulating case 33 and the transceiver main body 30 .
- the insulating foam member 7 b can restrict transmission of noise between the transceiver main body 30 and the battery 6 .
- a first ground electrode 131 described later is extended from the transceiver main body 30 , and is attached to an upper part of the internal wall surface of the insulating case 33 apart from the transmitting and receiving electrode 105 in a state that the first ground electrode 131 is not in contact with other devices (such as the battery 6 , and the wearable computer 1 ).
- a second ground electrode 161 and a third ground electrode 163 described later are extended from the transceiver main body 30 , and are attached to an upper part of the internal wall surface of the insulating case 33 apart from the transmitting and receiving electrode 105 in a state that these ground electrodes are not in contact with other devices (such as the battery 6 , and the wearable computer 1 ) and the first ground electrode 131 .
- the transmitting and receiving electrode 105 is attached to the bottom of the external wall surface and the side of the external wall surface of the insulating case 33 , thereby covering the whole of the transmitting and receiving electrode 105 with the insulating film 107 . Parts other than the operation/input surface of the wearable computer 1 are covered with the insulating case 11 .
- the transceiver main body 30 is similar to the conventional transceiver main body 30 ′ in that the transceiver main body 30 has the I/O (input/output) circuit 101 , the transmitter 103 , the transmitting and receiving electrode 105 , the insulating film 107 , the electric field sensor device 115 ′, and the receiving circuit 113 (the signal processing circuit 116 , and the waveform shaping circuit 117 ). These configurations are explained below.
- the I/O circuit 101 is used for the transceiver main body 30 to input and output information (data) to and from an external device such as the wearable computer 1 .
- the transmitter 103 consists of a transmitter circuit that induces, based on the information (data) output from the I/O circuit 101 , an electric field concerning this information in the human body 100 .
- the transmitting and receiving electrode 105 is used for the transmitter 103 to induce an electric field in the human body 100 , and is used as a transmitting antenna.
- the transmitting and receiving electrode 105 is also used to receive an electric field transmitted after being induced in the human body 100 , and is used as a receiving antenna.
- the insulating film 107 is an insulator film disposed between the transmitting and receiving electrode 105 and the human body 100 , thereby preventing the transmitting and receiving electrode 105 from directly contacting the human body 100 .
- the electric field sensor device 115 ′ has a function of detecting an electric field received by the transmitting and receiving electrode 105 , and converting this electric field into an electric signal as reception information.
- the signal processing circuit 116 of the receiving circuit 113 amplifies an electric signal transmitted from the electric field sensor unit 115 ′, limits the band of the electric signal, and removes unnecessary noise and an unnecessary signal component.
- the waveform shaping circuit 117 shapes the waveform (signal processing) of an electric signal transmitted from the signal processing circuit 116 , and supplies the processed electric signal to the wearable computer 1 via the I/O circuit 101 .
- the transmitter 103 , the receiving circuit 113 , and the I/O circuit 101 can be driven with the battery 6 .
- the electric field sensor unit 115 ′ is explained in detail with reference to FIG. 29 . This is explained again although the outline is already explained with reference to FIG. 4 .
- the electric field sensor unit 115 ′ restores the electric field received by the transceiver main body 30 to the electric signal. This processing is carried out by detecting the electric field according to an electro-optic method using laser light and an electro-optic crystal.
- the electric field sensor unit 115 ′ consists of the current source 119 , the laser diode 121 , the electro-optic element (electro-optic crystal) 123 , the first and the second wave plates 135 and 137 , the polarizing beam splitter 139 , the plural lenses 133 , 141 a , and 141 b , the photodiode 143 a and 143 b , and the first ground electrode 131 .
- the electro-optic element 123 has sensitivity in only the electric field that is coupled in a direction perpendicular to a proceeding direction of laser light that is emitted from the laser diode 121 .
- the electro-optic element 123 changes optical characteristic, that is, a birefringence index, according to the electric field intensity, and changes the polarization of the laser light based on the change of the birefringence index.
- the first electrode 125 and the second electrode 127 are provided on both side surfaces of the electro-optic element 123 , that are opposite in a vertical direction in FIG. 29 .
- the first electrode 125 and the second electrode 127 sandwich the proceeding direction of the laser light from the laser diode 121 in the electro-optic element 123 , and can couple the electric field with the laser light at a right angle.
- the electric field sensor unit 115 ′ is connected to the transmitting and receiving electrode 105 via the first electrode 125 .
- the second electrode 127 that is opposite to the first electrode 125 is connected to the first ground electrode 131 , and functions as a ground electrode to the first electrode 125 .
- the transmitting and receiving electrode 105 receives an electric field that is transmitted after being induced in the human body 100 , transmits this electric field to the first electrode 125 , and can couple the electric field with the electro-optic element 123 via the first electrode 125 .
- the laser light output from the laser diode 121 according to the current control from the current source 119 is made parallel light via the lens 133 .
- the first wave plate 135 adjusts the polarization state of the parallel laser light, and inputs the laser light to the electro-optic element 123 .
- the laser light that is incident to the electro-optic element 123 is propagated between the first and the second electrodes 125 and 127 within the electro-optic element 123 .
- the transmitting and receiving electrode 105 receives the electric field that is transmitted after being induced in the human body 100 as explained above, and couples this electric field with the electro-optic element 123 via the first electrode 125 .
- the electric field is formed from the first electrode 125 toward the second electrode 127 connected to the ground electrode 131 . Since the electric field is perpendicular to the proceeding direction of the laser light that is incident from the laser diode 121 to the electro-optic element 123 , the birefringence index as the optical characteristic of the electro-optic element 123 changes, and the polarization of the laser light changes accordingly.
- the second wave plate 137 adjusts the polarization state of the laser light of which polarization is changed by the electric field from the first electrode 125 in the electro-optic element 123 , and inputs the laser light to the polarizing beam splitter 139 .
- the polarizing beam splitter 139 separates the laser light incident from the second wave plate 137 , into a P wave and an S wave, and converts the laser light into optical intensity change.
- the first and the second lenses 141 a and 141 b condense respectively the laser light that is separated into the P wave component and the S wave component by the polarizing beam splitter 139 .
- the first and the second photodiodes 143 a and 143 b receive the laser light, convert the P wave light signal and the S wave light signal into respective current signals, and output the current signals.
- the current signals output from the first and the second photodiodes 143 a and 143 b are converted into voltage signals using resistors.
- the signal processing circuit 116 shown in FIG. 28 performs signal processing of amplification of the voltage signals and removal of noise.
- the first ground electrode 131 that becomes a reference point of voltage for the electric field sensor unit 115 ′ is extended to the outside of the transceiver main body 30 as shown in FIG. 27 .
- the second ground electrode 161 that becomes a reference point of voltage for the signal processing circuit 116 and the third ground electrode 163 that becomes a reference point of voltage for the transmitter 103 are extended in common to the outside.
- a using state of the transceiver 3 a and the wearable computer 1 according to the present embodiment is explained next with reference to FIG. 30 .
- the hand when the human hand (human body 100 ) holds the transceiver 3 a , the hand holds the bottom of the external wall surface and the side of the external wall surface of the insulating case 33 .
- the transmitting and receiving electrode 105 and the insulating film 107 cover not only the bottom of the external wall surface but also the side of the external wall surface of the insulating case 33 . Therefore, although transmission electric fields E 1 , E 2 , and E 3 are induced from the whole of the insulating case 33 , return of a part of the electric fields from the hand to the transceiver 3 via the side surface of the insulating case 33 is restricted.
- the transmitting electrode (the transmitting and receiving electrode 105 , in this case) is attached to a wide surface, including not only the bottom surface (bottom) but also the side surface (side) and the like, of the external wall surface of the insulating case 33 , and is covered with the insulating film 107 . Therefore, even when the human hand holds the transceiver 3 a , it is possible to prevent a part of the transmission electric fields returning from the hand back to the transceiver 3 a.
- first ground electrode 131 , the second ground electrode 161 , and the third ground electrode 163 are attached to the upper parts of the internal wall surface of the insulating case 33 apart from the transmitting and receiving electrode 105 , it is possible to prevent leakage of an unnecessary signal from the transmitting and receiving electrode 105 to the transceiver main body 30 , and the ground can be reinforced.
- the insulating foam member 7 a is sandwiched between the insulating case 33 and the transceiver main body 30
- the insulating foam member 7 b is sandwiched between the transceiver main body 30 and the battery 6 , it is possible to restrict noise from entering the transceiver main body 30 from the battery 6 and the insulating case 33 .
- a tenth embodiment is explained below with reference to FIG. 31 .
- FIG. 31 is an overall configuration diagram of a transceiver 32 and the wearable computer 1 according to the tenth embodiment. Constituent parts according to the tenth embodiment identical with those according to the ninth embodiment are assigned with the same reference numerals, and their explanation is omitted.
- insulating pillars 99 a and 99 b are employed in place of the insulating foam members 7 a and 7 b according to the ninth embodiment.
- contact areas between the insulator, the human body 100 , the transceiver main body 30 , and the battery 6 are made small, respectively. Therefore, there is a further significant effect that an unnecessary alternate current field is not induced.
- Wooden materials other than the foamed materials may be used for the insulating pillars 99 a and 99 b . However, a light and stiff member like paulownia is preferable.
- pillars are employed in the present embodiment, a block structure may be also employed.
- FIG. 32 is an overall configuration diagram of a transceiver 3 c and the wearable computer 1 according to the eleventh embodiment.
- the second and the third ground electrodes 161 and 163 are extended from the insulating case 33 of the transceiver 3 c , and are attached to the side surface (side) of the insulating case 11 of the wearable computer 1 .
- the second and the third ground electrodes 161 and 163 are positioned farther from the transmitting and receiving electrode 105 than that according to the ninth embodiment. Therefore, leakage of an unnecessary signal from the transmitting and receiving electrode 105 to the transceiver main body 30 can be prevented more securely, and the ground can be further reinforced.
- a twelfth embodiment is explained below with reference to FIG. 33 .
- FIG. 33 is an overall configuration diagram of a transceiver 3 d and the wearable computer 1 according to the twelfth embodiment. Constituent parts according to the twelfth embodiment identical with those according to the ninth embodiment are assigned with the same reference numerals, and their explanation is omitted.
- the first ground electrode 131 is extended from the insulating case 33 of the transceiver 3 d , and is attached to the side surface (side) of the insulating case 11 of the wearable computer 1 .
- the first ground electrode 131 is positioned farther from the transmitting and receiving electrode 105 than that according to the ninth embodiment. Therefore, leakage of an unnecessary signal from the transmitting and receiving electrode 105 to the transceiver main body 30 can be prevented more securely, and the ground can be further reinforced.
- a thirteenth embodiment is explained below with reference to FIG. 34 .
- FIG. 34 is an overall configuration diagram of a transceiver 3 e and the wearable computer 1 according to the thirteenth embodiment. Constituent parts according to the thirteenth embodiment identical with those according to the ninth embodiment are assigned with the same reference numerals, and their explanation is omitted.
- the transmitting and receiving electrode 105 is divided into a transmitting electrode 105 a exclusively used for transmission and a receiving electrode 105 b exclusively used for reception.
- the transmitting electrode 105 a is disposed at a position corresponding to the transmitting and receiving electrode 105 shown in FIG. 31 .
- the receiving electrode 105 b is disposed on an external bottom surface of the insulating film 107 a as shown in FIG. 34 .
- the receiving electrode 105 b is also covered with the insulating film 107 b to prevent the human body from being in direct contact with the receiving electrode 105 b .
- the insulating film 107 shown in FIG. 31 is expressed as the insulating film 107 a.
- the transmitting electrode 105 a is relatively large, and covers substantially the whole of the insulating case 33 , and the receiving electrode 105 b is small. Therefore, in addition to the effect of the ninth embodiment, there is an effect that a rate of returning of a part of the electric fields for transmission from the hand is small.
- the layout positions of the transmitting electrode 105 a and the receiving electrode 105 b may be replaced, like a transceiver 3 f shown in FIG. 35 (a fourteenth embodiment).
- one ground electrode is attached to the side surface of the insulating case 11 of the wearable computer 1 .
- the attaching mode is not limited to this.
- the first ground electrode 131 , and the second and third ground electrodes 161 and 163 can be attached to the side surface of the insulating case 11 of the wearable computer 1 , without the first ground electrode 131 contacted with the second and third ground electrodes 161 and 163 .
- the insulating foam member 7 a is sandwiched between the insulating case 33 and the transceiver main body 30
- the insulating foam member 7 b is sandwiched between the transceiver main body 30 and the battery 6 .
- the layout is not limited to this.
- an integrated insulating foam member 8 that covers both the battery 6 and the transceiver main body 30 without these members contacted with each other can be used.
- a cushion insulating member 9 in which gas like air is confined can be used instead of the foam member.
- laser light is branched (separated) before the laser light is incident to optical intensity modulating means.
- One laser light is input to the optical intensity modulating means, and is used as laser light for detecting an electric field.
- the other laser light is not input to the optical intensity modulating means, but is used as laser light for only removing noise from the laser light. Therefore, there is an effect that it is possible to remove noise from the laser light even when the optical intensity modulating means is used that cannot differentially take out an intensity modulation signal like the modulator that converts a polarization change of the laser light into an intensity change.
- the transmitting electrode is attached to a wide surface, including not only the bottom surface (bottom) but also the side surface (side), of the external wall surface of the insulating case. Therefore, even when the human hand holds the transceiver, it is possible to prevent a part of the transmission electric fields returning from the hand back to the transceiver.
Abstract
When a human hand (100) holds a transceiver (3 a), the hand holds a bottom of an external wall surface and a side of the external wall surface of an insulating case (33). Therefore, a transmitting and receiving electrode (105) and an insulating film (107) cover not only the bottom of the external wall surface but also the side of the external wall surface of the insulating case (33). A first ground electrode (131), a second ground electrode (161), and a third ground electrode (163) are attached to upper portions of the internal wall surface of the insulating case (33) apart from the transmitting and receiving electrode (105). An insulating foam member (7 a) is interposed between the insulating case (33) and a transceiver main body (30), and an insulating foam member (7 b) is interposed between the transceiver main body (30) and a battery (6).
Description
- This application is a divisional of U.S. application Ser. No. 10/524,485 filed Feb. 14, 2005, entitled “Electric Field Sensor Device, Transceiver, Positional Information Obtaining System, and Information Input System,” which is a 371 of PCT/JP2004/009159, filed Jun. 29, 2004 the entirety of which is incorporated herein by reference.
- The present invention relates to a transceiver that is used to carry out data communications between wearable computers, for example. More particularly, the present invention relates to a transceiver that can receive information via an electric field transmission medium by receiving information based on an electric field induced in the electric field transmission medium.
- The present invention further relates particularly to a transceiver including a transceiver main body that can transmit information via an electric field transmission medium by inducing an electric field based on the information to be transmitted from a transmitting electrode to the electric field transmission medium, a battery that drives the transceiver main body, and an insulating case that incorporates the transceiver main body.
- The present invention further relates to an electric field sensor device that detects an electric field by modulating the optical intensity of laser light based on an electric field to be detected, and a transceiver that has the electric field sensor device.
- The present invention further relates to positional information obtaining system including electric field inducing means for inducing an electric field in an electric field transmission medium corresponding to a position at which the electric field inducing means is brought into contact with the electric field transmission medium, and a transceiver that obtains information at the above position by receiving the electric field induced in the electric field transmission medium and converting the electric field into an electric signal.
- The present invention further relates to an information input system that obtains information based on positional information and the like from the positional information obtaining system.
- In recent years, a computer with a new concept of being wearable like clothes and able to be operated and used in this state is drawing attention. This computer is called a wearable computer, and is realized based on small and high-performance personal digital assistants.
- Progressive researches are also conducted on a technique of carrying out data communications between plural wearable computers via parts of a human body such as arms, shoulders, and bodies. This technique is already proposed in patent literatures and the like (for example, see Japanese Patent Application Laid-Open No. 2001-352298 (
pages 4 to 5, FIGS. 1 to 5)).FIG. 1 shows an image of carrying out communications between plural wearable computers via a human body. As shown inFIG. 1 , awearable computer 1 and atransceiver 3′ that is brought into contact with thewearable computer 1 constitute one set. A set of awearable computer 1 and atransceiver 3′ can carry out data communications with other set of awearable computer 1 and atransceiver 3′, via a human body. Thewearable computer 1 can also carry out data communications with other set of a personal computer (PC) 5 which is other than thewearable computer 1 mounted on the human body and atransceiver 3′a installed on a wall or the like, or a set of the PC 5 and atransceiver 3′b installed on a floor or the like. In this case, the PC 5 is not brought into contact with thetransceivers 3′a and 3′b unlike thewearable computer 1 and thetransceiver 3′, but is connected via acable 4, to thetransceivers 3′a and 3′b. - Regarding the data communications via a human body, a signal detection technique according to an electro-optic method using a laser light and an electro-optic crystal is utilized. With this arrangement, an electric field based on information (data) to be transmitted is induced in a human body (i.e., electric field transmission medium), and information based on the electric field induced in the human body is received, thereby achieving transmission and reception of the information. The technique of data communications via the human body is explained in detail with reference to
FIG. 2 . -
FIG. 2 is an overall configuration diagram of a transceivermain body 30′ that is used to carry out data communications via ahuman body 100. As shown inFIG. 2 , the transceivermain body 30′ is used in a state of being in contact with thehuman body 100 via a transmitting and receivingelectrode 105′ and aninsulating film 107′. The transceivermain body 30′ receives data supplied from thewearable computer 1 via an I/O (input/output)circuit 101, and transmits the data to atransmitter 103. Thetransmitter 103 induces an electric field in thehuman body 100 as an electric field transmission medium from the transmitting and receivingelectrode 105′ via theinsulating film 107′. Thetransmitter 103 transmits this electric field toother transceiver 3′ mounted on other part of thehuman body 100 via thehuman body 100. - In the transceiver
main body 30′, the transmitting and receivingelectrode 105′ receives an electric field induced in thehuman body 100 and transmitted from aseparate transceiver 3′ mounted on other part of thehuman body 100 via theinsulating film 107′. An electricfield sensor unit 110′ that constitutes an electricfield sensor device 115′ applies the received electric field to the above electro-optic crystal, thereby generating a polarization change and an intensity change in the laser light. Alight receiving circuit 152′ that constitutes the electricfield sensor device 115′ receives the polarization-changed and intensity-changed laser light, and converts the laser light into an electric signal, and processes this electric signal such as amplifies this electric signal. Asignal processing circuit 116 that constitutes areceiver circuit 113 removes a frequency component other than a frequency component concerning reception information as the electric field to be detected out of electric signals of various frequencies (i.e., extracts only the frequency component concerning the reception information) with a band pass filter that constitutes thesignal processing circuit 116, thereby removing noise from the electric signal. Awaveform shaping circuit 117 that constitutes thereceiver circuit 113 shapes the waveform (i.e., carries out a signal processing) of the electric signal that passes thesignal processing circuit 116, and supplies the waveform-shaped electric signal to thewearable computer 1 via the input/output circuit 101. - As shown in
FIG. 3 , the electrode can be divided into two for transmission and for reception, respectively. In other words, thetransmitter 103 induces an electric field in thehuman body 100 as an electric field transmission medium from a transmittingelectrode 105′a via aninsulating film 107′a. On the other hand, a receivingelectrode 105′b receives an electric field induced in thehuman body 100 and transmitted from aseparate transceiver 3′ mounted on other part of thehuman body 100 via aninsulating film 107′b. Other configurations and their operation are similar to those shown inFIG. 2 . - For example, as shown in
FIG. 1 , thewearable computer 1 mounted on the right arm makes thetransceiver 3′ induce an electric signal concerning transmission data as an electric field in thehuman body 100 as an electric field transmission medium, and transmit the electric field to other parts of thehuman body 100 as shown by a wavy line. On the other hand, thewearable computer 1 mounted on the left arm can make thetransceiver 3′ receive the electric field transmitted from thehuman body 100, return the electric field to the electric signal, and receive reception data. - The computer such as the
wearable computer 1 and a personal digital assistant such as a portable telephone need to be compact considering convenience of mounting on thehuman body 100 and carrying as shown inFIG. 1 . - However, along miniaturization of the computer and the personal digital assistant, input of information to the computer and the personal digital assistant become difficult.
- On the other hand, the electric
field sensor unit 110′ in the transceivermain body 30′ includes ones which convert the polarization change of laser light into the intensity change like a polarization modulator, and ones which directly convert the intensity change of the laser light like optical intensity modulators such as an electroabsorption (EA) optical intensity modulator and a Mach-Zehnder optical intensity modulator. - An electric
field sensor unit 110′a and alight receiving circuit 152′a that use apolarization modulator 123 is explained with reference toFIG. 4 andFIG. 5 , and then, an electricfield sensor unit 110′b and alight receiving circuit 152′b that use anoptical intensity modulator 124 is explained with reference toFIG. 6 toFIG. 8 . - First, as shown in
FIG. 4 , the electricfield sensor unit 110′a using thepolarization modulator 123 includes acurrent source 119, alaser diode 121, alens 133, thepolarization modulator 123 such as an electro-optic element (electro-optic crystal), a first and asecond wave plates beam splitter 139′, and a first and asecond lenses - The
light receiving circuit 152′a includes afirst photodiode 143 a, afirst load resistor 145 a, a firstconstant voltage source 147 a, asecond photodiode 143 b, asecond load resistor 145 b, a secondconstant voltage source 147 b, and adifferential amplifier 112. - Of the above, the
polarization modulator 123 has sensitivity in only the electric field that is coupled in a direction perpendicular to a proceeding direction of laser light that is emitted from thelaser diode 121. The intensity of the electric field changes optical characteristic, that is, a birefringence index, of thepolarization modulator 123. The change of the birefringence index of thepolarization modulator 123 changes the polarization of the laser light. Afirst electrode 125 and asecond electrode 127 are provided on both side surfaces of thepolarization modulator 123, that are opposite in a vertical direction in the drawing. Thefirst electrode 125 and thesecond electrode 127 face each other perpendicular to the proceeding direction of the laser light from thelaser diode 121 in thepolarization modulator 123, and can couple the electric field with the laser light at a right angle. - The electric
field sensor unit 110′a is connected to thereceiving electrode 105′b via thefirst electrode 125. Thesecond electrode 127 that is opposite to thefirst electrode 125 is connected to aground electrode 131, and functions as a ground electrode to thefirst electrode 125. Thereceiving electrode 105′b detects an electric field that is transmitted after being induced in thehuman body 100, transmits this electric field to thefirst electrode 125, and can couple the electric field with thepolarization modulator 123 via thefirst electrode 125. - With this arrangement, the laser light output from the
laser diode 121 according to the current control from thecurrent source 119 is made parallel light via thelens 133. Thefirst wave plate 135 adjusts the polarization state of the parallel laser light, and inputs the laser light to thepolarization modulator 123. The laser light that is incident to thepolarization modulator 123 is propagated between the first and thesecond electrodes polarization modulator 123. During the propagation of the laser light, thereceiving electrode 105′b detects the electric field that is transmitted after being induced in thehuman body 100, and couples this electric field with thepolarization modulator 123 via thefirst electrode 125. Then, the electric field is formed from thefirst electrode 125 toward thesecond electrode 127 connected to theground electrode 131. Since the electric field is perpendicular to the proceeding direction of the laser light that is incident from thelaser diode 121 to thepolarization modulator 123, the birefringence index as the optical characteristic of thepolarization modulator 123 changes, and the polarization of the laser light changes accordingly. - The
second wave plate 137 adjusts the polarization state of the laser light of which polarization is changed by the electric field from thefirst electrode 125 in thepolarization modulator 123, and inputs the laser light to the polarizingbeam splitter 139′. The polarizingbeam splitter 139′ separates the laser light input from thesecond wave plate 137, into a P wave and an S wave, and converts the laser light into optical intensity change. The first and thesecond lenses beam splitter 139′. The first and thesecond photodiodes first load resistor 145 a, the firstconstant voltage source 147 a, thesecond load resistor 145 b, and the secondconstant voltage source 147 b convert the current signals output from the first and thesecond photodiodes differential amplifier 112 can extract a voltage signal (intensity modulation signal) concerning reception information by differential. The extracted voltage signal is supplied to thesignal processing circuit 116 shown inFIG. 2 andFIG. 3 . - As shown in
FIG. 5 , the phase of a voltage signal Sa according to thefirst photodiode 143 a and the phase of a voltage signal Sb according to thesecond photodiode 143 b are deviated by 180 degrees. Therefore, thedifferential amplifier 112 amplifies the signal component of the opposite phase, and subtracts and removes noise of the in-phase laser light. - The
signal processing circuit 116 shown inFIG. 2 andFIG. 3 removes noise from the signal. Thewaveform shaping circuit 117 shapes the waveform of the signal, and supplies the signal to thewearable computer 1 via the input/output circuit 101. - The electric
field sensor unit 110′b and thelight receiving circuit 152′b that use theoptical intensity modulator 124 is explained with reference toFIG. 6 toFIG. 8 . Constituent parts identical with those of the electricfield sensor unit 110′a and thelight receiving circuit 152′a that use thepolarization modulator 123 are assigned with the same reference numerals. - As shown in
FIG. 6 , the electricfield sensor unit 110′b that uses theoptical intensity modulator 124 includes thecurrent source 119, thelaser diode 121, thelens 133, theoptical intensity modulator 124 such as an electroabsorption (EA) optical intensity modulator and a Mach-Zehnder optical intensity modulator, and thelens 141. - The
light receiving circuit 152′b includes thephotodiode 143, theload resistor 145, theconstant voltage source 147, and a (single)amplifier 118. - The
optical intensity modulator 124 is configured to change the optical intensity of the light that passes due to the intensity of the coupled electric field. Thefirst electrode 125 and thesecond electrode 127 are provided on both side surfaces of theoptical intensity modulator 124, that are opposite in a vertical direction in the drawing. Thefirst electrode 125 and thesecond electrode 127 face each other perpendicular to the proceeding direction of the laser light from thelaser diode 121 in theoptical intensity modulator 124, and can couple the electric field with the laser light at a right angle. - The electric
field sensor unit 110′b is connected to the receivingelectrode 105′b via thefirst electrode 125. Thesecond electrode 127 that is opposite to thefirst electrode 125 is connected to theground electrode 131, and functions as a ground electrode to thefirst electrode 125. The receivingelectrode 105′b detects an electric field that is transmitted after being induced in thehuman body 100, transmits this electric field to thefirst electrode 125, and can couple the electric field with theoptical intensity modulator 124 via thefirst electrode 125. - An electroabsorption (EA)
optical intensity modulator 124 a as one example of theoptical intensity modulator 124 is briefly explained with reference toFIG. 7 . - As shown in
FIG. 7 , when laser light having constant optical intensity is input, the electroabsorptionoptical intensity modulator 124 a varies the optical intensity according to the detection signal concerning the electric field with the constant optical intensity as the maximum. In other words, the intensity of the input laser light is attenuated based on the detection signal concerning the electric field. - A Mach-Zehnder
optical intensity modulator 124 b as one example of theoptical intensity modulator 124 is briefly explained with reference toFIG. 8 . - As shown in
FIG. 8 , the Mach-Zehnderoptical intensity modulator 124 b has twowaveguides substrate 201 formed on thesubstrate 201, thereby confining laser light input via alens 205 within thewaveguides first electrode 125 and thesecond electrode 127 apply an electric field to one of the branched laser lights and couple the electric field with the laser light. Thereafter, the Mach-Zehnderoptical intensity modulator 124 b emits the laser light via thelens 207. When the electric field is applied to one of the laser lights, the phase of this laser light can be slightly delayed or advanced from that of the laser light which is not applied with the electric field. - Referring back to
FIG. 6 , the laser light output from thelaser diode 121 based on the current control by thecurrent source 119 is made parallel light via thelens 133. The parallel laser light is incident to theoptical intensity modulator 124. The laser light that is incident to theoptical intensity modulator 124 is propagated between the first and thesecond electrodes optical intensity modulator 124. During the propagation of the laser light, the receivingelectrode 105′b detects the electric field that is transmitted after being induced in thehuman body 100 as explained above, and couples this electric field with theoptical intensity modulator 124 via thefirst electrode 125. Then, the electric field is formed from thefirst electrode 125 toward thesecond electrode 127 connected to theground electrode 131. Based on this coupling of the electric field, laser light of changed optical intensity is emitted. Thephotodiode 143 of thelight receiving circuit 152′b receives the laser light via thelens 141. As a result, thephotodiode 143 converts the laser light into a current signal according to the optical intensity of the laser light. Theload resistor 145 and theconstant voltage source 147 convert the current signal output from thephotodiode 143 into a voltage signal, and output this voltage signal. The output voltage signal is amplified by theamplifier 118, and is supplied to thesignal processing circuit 116 shown inFIG. 2 andFIG. 3 . - The
signal processing circuit 116 shown inFIG. 2 andFIG. 3 remove noise. Thewaveform shaping circuit 117 shapes the waveform, and supplies the signal to thewearable computer 1 via the input/output circuit 101. - However, the
optical intensity modulator 124 shown inFIG. 6 cannot extract the intensity modulation signal by differential as shown inFIG. 5 , unlike thepolarization modulator 123 shown inFIG. 4 that converts the polarization change of the laser light into the intensity change. Therefore, theoptical intensity modulator 124 cannot carry out a differential detection. When thephotodiode 143 directly receives the output from theoptical intensity modulator 124 without carrying out a differential detection, noise of the laser light cannot be removed, which results in poor S/N ratio of the reception signal and degradation of communication quality. - A human hand (human body 100) may hold a set of the
transceiver 3′ and thewearable computer 1, as shown inFIG. 9 . Thetransceiver 3′ shown inFIG. 9 has such a configuration that the transceivermain body 30′ is attached to the bottom of the internal wall surface of the insulatingcase 33 configured by an insulator, and abattery 6 that drives the transceivermain body 30′ is attached on the upper surface of the transceivermain body 30′. Further, the transmitting and receivingelectrode 105′ is attached to the bottom of the external wall surface of the insulatingcase 33, and this transmitting and receivingelectrode 105′ is covered with the insulatingfilm 107′. Parts other than the operation/input surface of thewearable computer 1 are covered with an insulatingcase 11. - However, when the hand holds the
transceiver 3′ as shown inFIG. 9 , even when an electric field E1 for transmission is induced in the human hand (human body 100) from the transmitting and receivingelectrode 105′, electric fields E2′ and E3′ thereof return from the hand to thetransceiver 3′ via the side surface of the insulatingcase 33. Therefore, thetransceiver 3′ does not carry out normal transmission operation. - The present invention has been achieved in the light of the above situation, and it is an object of the present invention to provide a technique of normally carrying out transmission and reception operation of a transceiver even if a human body as an electric field transmission medium contacts a wide surface out of an external wall surface of the transceiver, wherein the transceiver includes a transceiver main body that can transmit and receive information via the electric field transmission medium, a battery that drives this transceiver, and an insulating case that covers the transceiver main body.
- Further, the present invention has been made in the light of the above situation, and has an object of suppressing degradation of communication quality of an electric field sensor device using an optical intensity modulator to detect an electric field and a transceiver having this electric field sensor device.
- Further, the present invention has been made in the light of the above situation, and has an object of providing a technique of easily inputting information to a computer and a personal digital assistant each of which is used in a set with a transceiver that can transmit and receive information via an electric field transmission medium.
- In order to achieve the above objects, a first aspect of the present invention provides a transceiver including: a transmitting and receiving electrode that induces an electric field in an electric field transmission medium, and receives the electric field induced in said electric field transmission medium; a transceiver main body that generates said electric field based on information to be transmitted in said transmitting and receiving electrode, and converts said electric field generated in said transmitting and receiving electrode into reception information, thereby transmitting and receiving information via said electric field transmission medium; a first structure that is interposed between said transmitting and receiving electrode and said electric field transmission medium; a second structure that is interposed between said transceiver main body and said electric field transmission medium; a battery that drives said transceiver main body; and a third structure that is interposed between said transceiver main body and said battery, wherein each of said first, said second, and said third structures is composed of at least one of metal, a semiconductor, and an insulator, and is equivalent as a parallel circuit of a resistor and a capacitor.
- A second aspect of the present invention provides the transceiver according to the first aspect of the invention, wherein the impedance of said second structure and the impedance of said third structure are larger than the impedance of said first structure.
- A third aspect of the present invention provides the transceiver according to the second aspect of the invention, wherein said first structure is an insulating film that covers said transmitting and receiving electrode against said electric field transmission medium.
- A fourth aspect of the present invention provides the transceiver according to the second aspect of the invention, wherein said second structure and said third structure are insulating members.
- In order to achieve the above objects, a fifth aspect of the present invention provides a transceiver including: a transceiver main body that induces an electric field based on information to be transmitted in an electric field transmission medium from a transmitting electrode, thereby transmitting the information via said electric field transmission medium; a battery that drives said transceiver main body; and an insulating case that incorporates said transceiver main body, wherein said transmitting electrode is provided on the whole surface of a portion of an external wall surface of said insulating case, said electric field transmission medium closely approaching the portion, and is covered with an insulating film so as not to be in direct contact with said electric field transmission medium.
- A sixth aspect of the present invention provides the transceiver according to the fifth aspect of the invention, further including an insulating member between said battery and said transceiver main body.
- A seventh aspect of the present invention provides the transceiver according to the sixth aspect of the invention, wherein the insulating member is a foam member containing air.
- An eighth aspect of the present invention provides the transceiver according to the sixth aspect of the invention, wherein said insulating member is a plurality of wooden pillars.
- A ninth aspect of the present invention provides the transceiver according to the sixth aspect of the invention, wherein said insulating member is a cushion member having predetermined gas confined therein.
- A tenth aspect of the present invention provides the transceiver according to the fifth aspect of the invention, further including a ground electrode that defines a reference voltage which is necessary to drive said transceiver main body, and that is attached to an internal wall surface of said insulating case.
- An eleventh aspect of the present invention provides the transceiver according to the fifth aspect of the invention, further including a ground electrode that defines a reference voltage which is necessary to drive said transceiver main body, and that is attached to an external device at the outside of said insulating case.
- In order to achieve the above objects, a twelfth aspect of the present invention provides a transceiver including: a transceiver main body that induces an electric field based on information to be transmitted in an electric field transmission medium from a transmitting electrode, and receives information based on the electric field induced in said electric field transmission medium with a receiving electrode, thereby transmitting and receiving the information via said electric field transmission medium; a battery that drives said transceiver main body; and an insulating case that incorporates said transceiver main body, wherein said transmitting electrode is provided on the whole surface of a portion of an external wall surface of said insulating case, said electric field transmission medium closely approaching the portion, and is covered with a first insulating film so as not to be in direct contact with said electric field transmission medium, and said receiving electrode is provided on an external wall surface of said first insulating film, and is covered with a second insulating film so as not to be in direct contact with said electric field transmission medium.
- In order to achieve the above objects, a thirteenth aspect of the present invention provides a transceiver including: a transceiver main body that induces an electric field based on information to be transmitted in an electric field transmission medium from a transmitting electrode, and receives information based on the electric field induced in said electric field transmission medium with a receiving electrode, thereby transmitting and receiving the information via said electric field transmission medium; a battery that drives said transceiver main body; and an insulating case that incorporates said transceiver main body, wherein said receiving electrode is provided on the whole surface of a portion of an external wall surface of said insulating case, said electric field transmission medium closely approaching the portion, and is covered with a first insulating film so as not to be in direct contact with said electric field transmission medium, and said transmitting electrode is provided on an external wall surface of said first insulating film, and is covered with a second insulating film so as not to be in direct contact with said electric field transmission medium.
- In order to achieve the above objects, a fourteenth aspect of the present invention provides a transceiver that receives information based on an electric field induced in an electric field transmission medium, thereby receiving information via said electric field transmission medium, said transceiver including: memory means for storing information based on two electric signals and positional information determined according to the electric signal information, by relating these pieces of information to each other; electric field detecting means for detecting an electric field transmitted after being induced in said electric field transmission medium, and converting a change of said electric field into an electric signal; a band pass filter that passes only a signal component having a predetermined band containing said two electric signals out of electric signals obtained by said electric field detecting means; and position conversion processing means for referring to said memory means and obtaining positional information corresponding to the information based on said two electric signals that pass said band pass filter.
- A fifteenth aspect of the present invention provides the transceiver according to the fourteenth aspect of the invention, wherein said memory means stores information based on signal intensity of two electric signals and positional information determined according to the signal intensity information, by relating these pieces of information to each other, said band pass filter includes: a first band pass filter that passes only a signal component having a first band containing one of said electric signals obtained by said electric field detecting means; and a second band pass filter that passes only a signal component having a second band different from said first band containing the other of said electric signals obtained by said electric field detecting means, said transceiver further comprising signal intensity measuring means for measuring signal intensity of a signal component which passes through said first band pass filter and signal intensity of a signal component which passes through said second band pass filter, wherein said position conversion processing means refers to said memory means and obtains positional information corresponding to the information based on signal intensity of the signal component which passes through said first band pass filter and signal intensity of the signal component which passes through said second band pass filter measured by said signal intensity measuring means.
- A sixteenth aspect of the present invention provides the transceiver according to the fifteenth aspect of the invention, wherein said memory means stores information of an intensity difference between electric signals and positional information determined according to the information, by relating these pieces of information to each other, and said position conversion processing means calculates a difference between intensity of the signal component which passes through said first band pass filter and intensity of the signal component which passes through said second band pass filter measured by said signal intensity measuring means, refers to said memory means, and obtains the positional information corresponding to the intensity difference.
- A seventeenth aspect of the present invention provides the transceiver according to the sixteenth aspect of the invention, wherein an external device can rewrite the relation between the information of the intensity difference and the positional information stored in said memory means.
- An eighteenth aspect of the present invention provides the transceiver according to the fifteenth aspect of the invention, wherein said memory means stores information of an intensity ratio between electric signals and positional information determined according to the intensity ratio information, by relating these pieces of information to each other, and said position conversion processing means calculates a ratio of intensity of the signal component which passes through said first band pass filter to intensity of the signal component which passes through said second band pass filter measured by said signal intensity measuring means, refers to said memory means, and obtains the positional information corresponding to the intensity ratio.
- A nineteenth aspect of the present invention provides the transceiver according to the eighteenth aspect of the invention, wherein an external device can rewrite the relation between the information of the intensity ratio and the positional information stored in said memory means.
- A twentieth aspect of the present invention provides the transceiver according to the fourteenth aspect of the invention, wherein said memory means stores information based on a phase difference between two electric signals and positional information determined according to the phase difference information, by relating these pieces of information to each other, said band pass filter includes: a first band pass filter that passes only a signal component having a first band containing one of said electric signals obtained by said electric field detecting means; and a second band pass filter that passes only a signal component having a second band different from said first band containing the other of said electric signals obtained by said electric field detecting means, the transceiver further comprising phase detecting means for detecting a phase of the signal component which passes through said first band pass filter and a phase of the signal component which passes through said second band pass filter, wherein said position conversion processing means calculates a difference between the phase of the signal component which passes through said first band pass filter and the phase of the signal component which passes through said second band pass filter detected by said phase detecting means, refers to said memory means, and obtains the positional information corresponding to the phase difference.
- A twenty first aspect of the present invention provides the transceiver according to the twentieth aspect of the invention, wherein an external device can rewrite the relation between the information of the phase difference and the positional information stored in said memory means.
- In order to achieve said objects, a twenty second aspect of the present invention provides a positional information obtaining system including: an electric field transmission sheet that transmits an electric charge and has any point thereon contacted by an electric field transmission medium; a first and a second signal generators that are disposed respectively at different positions on said electric field transmission sheet, and induce electric fields based on electric signals having a first band and a second band respectively on said electric field transmission sheet; and a transceiver that receives information based on an electric field induced in said electric field transmission medium, thereby receiving the information via said electric field transmission medium, wherein said transceiver includes: memory means for storing information based on two electric signals and positional information determined according to the electric signal information, by relating these pieces of information to each other; electric field detecting means for detecting an electric field transmitted after being induced in said electric field transmission medium, and converting a change of said electric field into an electric signal; a band pass filter that passes only a signal component having a predetermined band containing said two electric signals out of electric signals obtained by said electric field detecting means; and position conversion processing means for referring to said memory means and obtaining the positional information corresponding to the information based on said two electric signals that pass said band pass filter.
- In order to achieve said objects, a twenty third aspect of the present invention provides an information input system including: an electric field transmission sheet that transmits an electric charge and has any point thereon contacted by an electric field transmission medium; a first and a second signal generators that are disposed respectively at different positions on said electric field transmission sheet, and induce electric fields based on electric signals having a first band and a second band respectively on said electric field transmission sheet; a transceiver that receives information based on an electric field induced in said electric field transmission medium, thereby receiving the information via said electric field transmission medium, said transceiver including: memory means for storing information based on two electric signals and positional information determined according to the electric signal information, by relating these pieces of information to each other; electric field detecting means for detecting an electric field transmitted after being induced in said electric field transmission medium, and converting a change of said electric field into an electric signal; a band pass filter that passes only a signal component having a predetermined band containing said two electric signals out of electric signals obtained by said electric field detecting means; and position conversion processing means for referring to said memory means and obtaining the positional information corresponding to the information based on said two electric signals that pass said band pass filter; and a wearable computer that has computer memory means that stores positional information and input information corresponding to the positional information by relating these pieces of information to each other, refers to said computer memory means based on the positional information input from said transceiver, and obtains the input information.
- In order to achieve said objects, a twenty fourth aspect of the present invention provides an information input system including: electric field inducing means that is contacted or operated by an electric field transmission medium, and induces an electric field in said electric field transmission medium according to a physical quantity based on the contact or operation; a transceiver that receives the electric field induced in said electric field transmission medium, applies the electric field to a polarization modulator or an optical intensity modulator, polarization-modulates or optical intensity-modulates laser light according to the electric field, converts the polarization-modulated or optical intensity-modulated laser light into an electric signal, extracts an electric signal having a frequency component concerning a physical quantity based on said contact or operation from the converted electric signals, and outputs the electric signal concerning the physical quantity based on said contact or operation; and information processing means for inputting therein the electric signal concerning the physical quantity based on said contact or operation from said transceiver, and obtains information corresponding to the physical quantity based on said contact or operation by said electric field transmission medium.
- In order to achieve said objects, a twenty fifth aspect of the present invention provides an electric field sensor device that modulates optical intensity of laser light based on an electric field to be detected, thereby detecting said electric field, said electric field sensor device having an electric field sensor unit and a light receiving circuit, wherein said electric field sensor unit includes: laser light emitting means; branching means for branching a laser light emitted from said laser light emitting means into a first laser light and a second laser light that are different from each other; and optical intensity modulating means with which said electric field to be detected is coupled, that modulates the optical intensity of said first laser light based on said coupled electric field, and said light receiving circuit includes: first light/voltage converting means for converting the optical intensity of said first laser light modulated by said optical intensity modulating means into a voltage signal; a second light/voltage converting means for converting the optical intensity of said second laser light branched by said branching means into a voltage signal; and differential amplifying means for differentially amplifying the voltage signal obtained by conversion by said first light/voltage converting means and the voltage signal obtained by conversion by said second light/voltage converting means.
- A twenty sixth aspect of the present invention provides the electric field sensor device according to the twenty fifth aspect of the invention, wherein said electric field sensor unit further includes an optical variable attenuator that attenuates the optical intensity of said second laser light obtained by branching by said branching means, and said second photoelectrical converting means inputs therein said second laser light attenuated by said optical variable attenuator.
- A twenty seventh aspect of the present invention provides the electric field sensor device according to the twenty fifth aspect of the invention, wherein said electric field sensor unit further includes a first optical variable attenuator that attenuates the optical intensity of said first laser light obtained by branching by said branching means at a predetermined rate, and a second optical variable attenuator that attenuates the optical intensity of said second laser light obtained by branching by said branching means at a rate higher than an attenuation rate of said first optical variable attenuator, said optical intensity modulating means inputs therein said first laser light attenuated by said first optical variable attenuator, and said second photoelectrical converting means inputs therein said second laser light attenuated by said second optical variable attenuator.
- A twenty eighth aspect of the present invention provides the electric field sensor device according to the twenty fifth aspect of the invention, wherein said first light/voltage converting means includes: first light/current converting means for converting the optical intensity of said first laser light modulated by said optical intensity modulating means into a current signal; a first voltage source that applies an inverse bias voltage to said first light/current converting means; and a first load resistor that converts said current signal obtained by conversion by said first light/current converting means into a voltage signal, and said second light/voltage converting means includes: second light/current converting means for converting the intensity of said second laser light obtained by branching by said branching means into a current signal; a second voltage source that applies an inverse bias voltage to said second light/current converting means; and a second load resistor that converts said current signal obtained by conversion by said second light/current converting means into a voltage signal.
- A twenty ninth aspect of the present invention provides the electric field sensor device according to the twenty eighth aspect of the invention, wherein at least one of said first load resistor and said second load resistor is a variable resistor.
- A thirtieth aspect of the present invention provides the electric field sensor device according to the twenty eighth aspect of the invention, wherein at least one of said first voltage source and said second voltage source is a variable voltage source.
- A thirty first aspect of the present invention provides the electric field sensor device according to the twenty fifth aspect of the invention, wherein said light receiving circuit further includes amplifying means for amplifying at least one of the voltage signal obtained by conversion by said first light/voltage converting means and the voltage signal obtained by conversion by said second light/voltage converting means.
- In order to achieve said objects, a thirty second aspect of the present invention provides a transceiver that receives information based on an electric field induced in an electric field transmission medium, thereby receiving the information via said electric field transmission medium, said transceiver including: said electric field sensor device according to the twenty fifth aspect; a signal processing circuit that at least removes a noise from a voltage signal output from said electric field sensor device; noise detecting means for detecting quantity of a noise component of the voltage signal output from said signal processing circuit; and a control signal generator that generates a control signal to variably control a variable value of said electric field sensor unit or said light receiving circuit based on the detection data output from said noise detecting means.
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FIG. 1 is an image diagram of carrying out communications between plural wearable computers via a human body. -
FIG. 2 is an overall configuration diagram of a conventional transceiver main body. -
FIG. 3 is an overall configuration diagram of another conventional transceiver main body. -
FIG. 4 is a detailed configuration diagram of an electric field sensor unit and a light receiving circuit of a conventional (polarization modulation type) transceiver main body. -
FIG. 5 is a diagram showing a waveform of an input signal of a differential amplifier shown inFIG. 4 . -
FIG. 6 is a detailed configuration diagram of an electric field sensor unit and a light receiving circuit of a conventional (optical intensity modulation type) transceiver main body. -
FIG. 7 is a principle diagram when an optical intensity modulator used in the electric field sensor unit of the conventional (optical intensity modulation type) transceiver main body is an electroabsorption type. -
FIG. 8 is a principle diagram when the optical intensity modulator used in the electric field sensor unit of the conventional (optical intensity modulation type) transceiver main body is a Mach-Zehnder. -
FIG. 9 is an image diagram showing a using state of a combination of a transceiver and a wearable computer that are held in a human hand. -
FIG. 10 is an image diagram of a front view showing a using state of a transceiver and a wearable computer according to a first embodiment of the present invention. -
FIG. 11 is an image diagram of a top plan view showing a using state of the transceiver and the wearable computer according to the first embodiment of the present invention. -
FIG. 12 is a diagram showing frequency bands for information communication, a signal generator A, and a signal generator B, respectively. -
FIG. 13 is an overall configuration diagram of a transceiver main body within the transceiver according to the first embodiment. -
FIG. 14 is an overall configuration diagram of a transceiver main body within a transceiver according to a second embodiment. -
FIG. 15 is a diagram showing a concrete example of an electric field transmission sheet according to the first and the second embodiments. -
FIG. 16 is a diagram showing a concrete example of the electric field transmission sheet according to the first and the second embodiments. -
FIG. 17 is a diagram showing a concrete example of the electric field transmission sheet according to the first and the second embodiments. -
FIG. 18 is an overall configuration diagram of a transceiver main body according to third to seventh embodiments of the present invention. -
FIG. 19 is a detailed configuration diagram of an electric field sensor unit and a light receiving circuit of a transceiver main body according to the third embodiment. -
FIG. 20 is a detailed configuration diagram of an electric field sensor unit and a light receiving circuit of a transceiver main body according to the fourth embodiment. -
FIG. 21 is a detailed configuration diagram of an electric field sensor unit and a light receiving circuit of a transceiver main body according to the fifth embodiment. -
FIG. 22 is a detailed configuration diagram of an electric field sensor unit and a light receiving circuit of a transceiver main body according to the sixth embodiment. -
FIG. 23 is a detailed configuration diagram of an electric field sensor unit and a light receiving circuit of a transceiver main body according to the seventh embodiment. -
FIG. 24 is an overall configuration diagram of a transceiver main body according to an eighth embodiment of the present invention. -
FIG. 25 is a diagram showing an equivalent circuit between a human body, a transmitting and receiving electrode, and a transceiver main body. -
FIG. 26 is a diagram showing an equivalent circuit between a human body, a transceiver main body, and a battery. -
FIG. 27 is an overall configuration diagram of a transceiver and a wearable computer according to a ninth embodiment of the present invention. -
FIG. 28 is a functional block diagram showing mainly a function of the transceiver main body. -
FIG. 29 is a detailed configuration diagram of an electric field sensor device. -
FIG. 30 is an image diagram showing a using state of the transceiver and the wearable computer shown inFIG. 27 . -
FIG. 31 is an overall configuration diagram of a transceiver and a wearable computer according to a tenth embodiment of the present invention. -
FIG. 32 is an overall configuration diagram of a transceiver and a wearable computer according to an eleventh embodiment of the present invention. -
FIG. 33 is an overall configuration diagram of a transceiver and a wearable computer according to a twelfth embodiment of the present invention. -
FIG. 34 is an overall configuration diagram of a transceiver and a wearable computer according to a thirteenth embodiment of the present invention. -
FIG. 35 is an overall configuration diagram of a transceiver and a wearable computer according to a fourteenth embodiment of the present invention. -
FIG. 36 is a diagram showing other embodiment of the present invention. -
FIG. 37 is a diagram showing other embodiment of the present invention. - Exemplary embodiments (hereinafter, referred to as “embodiments”) according to the present invention are explained in detail below with reference to the drawings.
- A
transceiver 3 according the embodiments of the present invention induces an electric field based on information to be transmitted in an electric field transmission medium (such as the human body 100), and receives information based on an electric field induced in the electric field transmission medium, thereby transmitting and receiving information via the electric field transmission medium. - First, an embodiment of a transceiver that can easily input information to a particularly miniaturized wearable computer is explained.
- A first embodiment is explained below with reference to the drawings.
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FIG. 10 is an image diagram of a front view showing a using state of thetransceiver 3 and thewearable computer 1 according to the first embodiment.FIG. 11 is an image diagram of a top plan view showing the using state. - As shown in
FIG. 10 , an insulatingsheet 301 is adhered to a flat surface of a table 300, and an electricfield transmission sheet 302 that can transmit an electric field is adhered to a flat surface of the insulatingsheet 301. Signal generators A and B are disposed at different comers on the flat surface of the electricfield transmission sheet 302. As shown inFIG. 11 , when the electricfield transmission sheet 302 is rectangular, these signal generators are disposed at different optional comers. - Each of the signal generators A and B has a configuration similar to that including the
transmitter 103, the transmittingelectrode 105′a, and the insulatingfilm 107′a as shown inFIG. 3 , and can induce an electric field based on an electric signal concerning transmission frequencies fa and fb respectively on the electricfield transmission sheet 302 as shown inFIG. 12 . -
FIG. 13 is an overall configuration diagram of a transceivermain body 30 a within thetransceiver 3 according to the present embodiment. - As shown in
FIG. 13 , the transceivermain body 30 a is similar to the conventional transceivermain body 30′ in that the transceivermain body 30 a has the I/O (input/output)circuit 101, thetransmitter 103, the transmittingelectrode 105 a, the insulatingfilms electrode 105 b, the electricfield sensor device 115, thesignal processing circuit 116, and thewaveform shaping circuit 117. The transceivermain body 30 a according to the present embodiment further has band pass filters 11 a and 11 b, signalintensity measuring units position conversion processor 15, and amemory 17. - The I/
O circuit 101 is used for the transceivermain body 30 a to input and output information (data) to and from an external device such as thewearable computer 1. Thetransmitter 103 consists of a transmitter circuit that induces, based on the information (data) output from the I/O circuit 101, an electric field concerning this information in thehuman body 100. The transmittingelectrode 105 a is used for thetransmitter 103 to induce an electric field in thehuman body 100, and is used as a transmitting antenna. The insulatingfilm 107 a is an insulator film disposed between the transmittingelectrode 105 a and thehuman body 100, and prevents the transmittingelectrode 105 a from directly contacting thehuman body 100. - The receiving
electrode 105 b is used to receive an electric field transmitted after being induced in thehuman body 100 from thewearable computer 1 and thetransceiver 3′ that are mounted on other part of thehuman body 100 and thePC 5 and thetransceivers 3′a and 3′b, and is used as a receiving antenna. The insulatingfilm 107 b is an insulator film disposed between the receivingelectrode 105 b and thehuman body 100, like theinsulating film 107 a. - The electric
field sensor device 115 has a function of detecting an electric field received by the receivingelectrode 105 b, and converting this electric field into an electric signal as reception information. Thesignal processing circuit 116 consists of anamplifier 114 that amplifies an electric signal transmitted from the electricfield sensor device 115, and aband pass filter 151. Thisband pass filter 151 is a filter circuit having a characteristic of limiting the band of an electric signal output from theamplifier 114 and removes unnecessary noise and an unnecessary signal component, thereby passing a signal component of only a frequency band of a constant width (f1 to f2) for information communication as shown inFIG. 12 out of the electric signals output from theamplifier 114. - The
waveform shaping circuit 117 shapes the waveform (signal processing) of an electric signal transmitted from thesignal processing circuit 116, and supplies the processed electric signal to thewearable computer 1 via the I/O circuit 101. - The
band pass filter 11 a is a filter circuit having a characteristic of limiting the band of an electric signal output from theamplifier 114 and removes unnecessary noise and an unnecessary signal component, thereby passing a signal component of only a frequency band (fa) for the signal generator A as shown inFIG. 12 out of the electric signals output from theamplifier 114. The signalintensity measuring unit 13 a is a circuit that measures signal intensity of an electric signal concerning the signal component that is passed by theband pass filter 11 a. - The
band pass filter 11 b is a filter circuit having a characteristic of limiting the band of an electric signal output from theamplifier 114 and removes unnecessary noise and an unnecessary signal component, thereby passing a signal component of only a frequency band (fb) for the signal generator B as shown inFIG. 12 out of the electric signals output from theamplifier 114. The signalintensity measuring unit 13 b is a circuit that measures signal intensity of an electric signal concerning the signal component that is passed by theband pass filter 11 b. - The
memory 17 stores an intensity difference between two electric signals and a specific position in a two-dimensional space by relating these pieces of information to each other. According to the present embodiment, an optional position on the electricfield transmission sheet 302 shown inFIG. 10 andFIG. 11 and the intensity difference are related to each other in advance. An external device such as thewearable computer 1 can rewrite the relationship between the intensity difference and the specific position stored in thememory 17, via the I/O circuit 101. - The
position conversion processor 15 is a CPU (central processing unit) or the like that calculates a difference between the signal intensity measured by the signalintensity measuring unit 13 a and the signal intensity measured by the signalintensity measuring unit 13 b, and collates this intensity difference with the intensity difference stored in thememory 17, thereby converting the calculated intensity difference into a specific position in a two-dimensional space. - A method of specifying a position using the transceiver
main body 30 a and the signal generators A and B according to the present embodiment is explained next. - As shown in
FIG. 10 andFIG. 11 , in the state that the signal generators A and B are installed on the electricfield transmission sheet 302 and driven, a person who wears thewearable computer 1 and thetransceiver 3 touches a specific position α on the electricfield transmission sheet 302. As a result, the receivingelectrode 105 b receives electric fields from the signal generators A and B via the finger (human body 100) and the insulatingfilm 107 b. The electricfield sensor device 115 couples (applies) the received electric fields to an electro-optic crystal, not shown, of the electricfield sensor device 115, converts the electric fields into electric signals, and transmits the electric signals to thesignal processing circuit 116. Theamplifier 114 of thesignal processing circuit 116 amplifies the electric signals, and transmits the amplified electric signals to theband pass filter 151. However, the electric signals concerning the electric fields from the signal generators A and B do not pass through theband pass filter 116. - The electric signals transmitted from the
amplifier 114 are also transmitted to the band pass filters 11 a and 11 b. - The
band pass filter 11 a passes the signal component of only the band (fa) for the signal generator A out of the electric signals concerning the electric fields from the signal generators A and B, and transmits this signal component to the signalintensity measuring unit 13 a. The signalintensity measuring unit 13 a measures signal intensity of the electric signal concerning the signal component that is passed by theband pass filter 11 a. - On the other hand, the
band pass filter 11 b passes the signal component of only the band (fb) for the signal generator B out of the electric signals concerning the electric fields from the signal generators A and B, and transmits this signal component to the signalintensity measuring unit 13 b. The signalintensity measuring unit 13 b measures signal intensity of the electric signal concerning the signal component that is passed by theband pass filter 11 b. - The
position conversion processor 15 calculates an intensity difference between the signal intensity measured by the signalintensity measuring unit 13 a and the signal intensity measured by the signalintensity measuring unit 13 b, and collates this intensity difference with the intensity difference stored in thememory 17, thereby converting the calculated intensity difference into the specific position α in the two-dimensional space on the electric field transmission sheet 202. - Finally, the
position conversion processor 15 transmits the position information (data) at the specific position α obtained by theposition conversion processor 15 to thewearable computer 1 via the I/O circuit 101. - As explained above, according to the present embodiment, the intensity difference between the signal intensity measured by the signal
intensity measuring unit 13 a and the signal intensity measured by the signalintensity measuring unit 13 b is calculated. This intensity difference is collated with the intensity difference stored in thememory 17, thereby converting the calculated intensity difference into the specific position in the two-dimensional space. With this arrangement, the positional information at the specific position ox on the electricfield transmission sheet 302 that is touched with the finger (human body 100) can be input to thewearable computer 1 or the like. Therefore, there is an effect that information can be easily input to thewearable computer 1 or the like. - In the above embodiment, the
position conversion processor 15 calculates the intensity difference between the signal intensity measured by the signalintensity measuring unit 13 a and the signal intensity measured by the signalintensity measuring unit 13 b. Theposition conversion processor 15 may also calculate an intensity ratio of the signal intensity measured by the signalintensity measuring unit 13 a to the signal intensity measured by the signalintensity measuring unit 13 b. In this case, thememory 17 needs to store the intensity ratio between the two electric signals and the specific position in the two-dimensional space by relating these pieces of information to each other. - A second embodiment is explained with reference to the drawings.
-
FIG. 14 is an overall configuration diagram of a transceivermain body 30 b within a transceiver according to the second embodiment. Constituent parts that are identical with those according to the first embodiment are assigned with same reference numerals, and their explanation is omitted. - A
phase detector 23 a shown inFIG. 14 is a circuit that detects a phase of an electric signal concerning a signal component which is passed by theband pass filter 11 a.A phase detector 23 b is a circuit that detects a phase of an electric signal concerning a signal component which is passed by theband pass filter 11 b. - A
memory 27 stores a phase difference between two electric signals and a specific position in a two-dimensional space by relating these pieces of information to each other. According to the present embodiment, an optional position on the electricfield transmission sheet 302 shown inFIG. 10 andFIG. 11 and the phase difference are related to each other in advance. An external device such as thewearable computer 1 can rewrite the relationship between the phase difference and the specific position stored in thememory 27, via the I/O circuit 101. - A
position conversion processor 25 is a CPU or the like that calculates a difference between the phase measured by thephase detector 23 a and the phase measured by thephase detector 23 b, and collates this phase difference with the phase difference stored in thememory 27, thereby converting the calculated phase difference into a specific position in a two-dimensional space. - A method of specifying a position using the
transceiver 30 b and the signal generators A and B according to the present embodiment is explained next. - As shown in
FIG. 10 andFIG. 11 , in the state that the signal generators A and B are installed on the electricfield transmission sheet 302 and driven, a person who wears thewearable computer 1 and thetransceiver 3 touches the specific position α on the electricfield transmission sheet 302. As a result, the receivingelectrode 105 b receives electric fields from the signal generators A and B via the finger (human body 100) and the insulatingfilm 107 b. The electricfield sensor device 115 couples (applies) the received electric fields to an electro-optic crystal, not shown, of the electricfield sensor device 115, converts the electric fields into electric signals, and transmits the electric signals to thesignal processing circuit 116. Theamplifier 114 of thesignal processing circuit 116 amplifies the electric signals, and transmits the amplified electric signals to theband pass filter 151. However, the electric signals concerning the electric fields from the signal generators A and B do not pass through theband pass filter 151. - The electric signals transmitted from the
amplifier 114 are also transmitted to the band pass filters 11 a and 11 b. - The
band pass filter 11 a passes the signal component of only the band (fa) for the signal generator A out of the electric signals concerning the electric fields from the signal generators A and B, and transmits this signal component to thephase detector 23 a. Thephase detector 23 a detects a phase of the electric signal concerning the signal component that is passed by theband pass filter 11 a. - On the other hand, the
band pass filter 11 b passes the signal component of only the band (fb) for the signal generator B out of the electric signals concerning the electric fields from the signal generators A and B, and transmits this signal component to thephase detector 23 b. Thephase detector 23 b detects a phase of the electric signal concerning the signal component that is passed by theband pass filter 11 b. - The
position conversion processor 25 calculates a phase difference between the phase measured by thephase detector 23 a and the phase measured by thephase detector 23 b, and collates this phase difference with the phase difference stored in thememory 27, thereby converting the calculated phase difference into the specific position ox in the two-dimensional space on the electricfield transmission sheet 302. - Finally, the
position conversion processor 25 transmits the position information (data) at the specific position α obtained by theposition conversion processor 25 to thewearable computer 1 via the I/O circuit 101. - As explained above, according to the present embodiment, effect similar to that according to the first embodiment is obtained.
- Concrete examples according to the first and the second embodiments are explained below with reference to
FIG. 15 toFIG. 17 . -
FIG. 15 andFIG. 16 show an example that the above embodiments are applied to an electricfield transmission sheet 302 a and a keyboard of a personal computer. As shown inFIG. 15 , a picture of a keyboard is printed on the electricfield transmission sheet 302 a. When a person touches a specific position α1, it is possible to specify the touched key based on respective distances x1 and y1 from the signal generators A and B. - As described above, positional information, that is, the distances x1 and y1 from the signal generators A and B respectively in this case, is transmitted from the
transceiver 3 to thewearable computer 1. Thewearable computer 1 has a table showing a relationship between the positional information and the input information that is the same as the relationship between the position on the electricfield transmission sheet 302 a and the print information at this position. As a result, thewearable computer 1 can understand the information that the person intends to indicate. -
FIG. 17 shows an example that the above embodiments are applied to an electricfield transmission sheet 302 b such as a touch panel, a touch screen, and a showcase. Similarly, when a person touches a specific position (x2, for example, it is possible to specify the touched position based on respective distances x2 and y2 from the signal generators A and B - According to the above embodiments, “two signal generators” and “an electric field transmission sheet” are used. When a person touches the electric field transmission sheet with a hand (finger), electric signals from the two signal generators are transmitted to a transceiver via the hand (human body 100). The transceiver separates the two electric signals, and obtains information about distances from the two signal generators to the touched position, based on the two electric signals. The gist of the present invention is not limited to this.
- For example, the present invention can be applied not only to a two-dimensional plane surface but also to a three-dimensional space. In other words, when “three signal generators” and a three-dimensional “electric field transmission medium” are used, the three signal generators can transmit signals to a finger that indicates a certain three-dimensional point via the electric field transmission medium. The transceiver can separate the three signals. As a result, the transceiver obtains positional information of the point indicated by the person within a three-dimensional space. This information is transmitted to an information device such as a wearable computer. When a person indicates a certain point within a three-dimensional space, the intended information can be input to the information device.
- When the transceiver has a sufficient processing speed, the transceiver can understand the information of the position of a finger as information about the move of the finger. In other words, for example, when the electric field transmission sheet is touched with the finger, the transceiver can understand the move of the finger in real time. When this information is transmitted to an information device such as a wearable computer, the move information itself or information relevant to the move information intended by a person can be input to the information device.
- The information transmitted to the transceiver via the human body is not limited to a signal based on which a position (speed) can be obtained. For example, when the electric field transmission sheet has a function of detecting a pressure, the pressure signal can be also converted into an electric field, and can be transmitted to the transceiver via a finger or the like. In this case, the transceiver can obtain the information of pressing force that a person intends. When this information is transmitted to an information device such as a wearable computer, the information device can obtain information corresponding to the pressing force.
- While it is explained above that the information device such as a wearable computer has information corresponding to position information or pressure information intended by a person, the transceiver itself may have this information. With this arrangement, the transceiver itself can obtain information intended by a person. Alternatively, a third device other than the information device such as a wearable computer and the transceiver can have this information, and the information device and the transceiver can obtain the information from this third device.
- An embodiment of a transceiver that employs an optical intensity modulator in the electric field sensor unit is explained next.
- An electric
field sensor device 115 a, and an optical intensity modulation transceiver (hereinafter simply referred to as a “transceiver”) 3 having the electricfield sensor device 115 a according to a third embodiment of the present invention are explained with reference toFIG. 18 andFIG. 19 . -
FIG. 18 is an overall configuration diagram of a transceivermain body 30 c that is used to carry out data communications via thehuman body 100.FIG. 18 is an overall configuration diagram common to the third to seventh embodiments. - As shown in
FIG. 18 , the transceivermain body 30 c has the I/O (input/output)circuit 101, thetransmitter 103, the transmittingelectrode 105 a, the receivingelectrode 105 b, the insulatingfilms field sensor unit 110, and a light receiving circuit 152), thesignal processing circuit 116, and thewaveform shaping circuit 117. - The I/
O circuit 101 is used for the transceivermain body 3 c to input and output information (data) to and from an external device such as thewearable computer 1. Thetransmitter 103 consists of a transmitter circuit that induces, based on the information (data) output from the I/O circuit 101, an electric field concerning this information in thehuman body 100. The transmittingelectrode 105 a is used for thetransmitter 103 to induce an electric field in thehuman body 100, and is used as a transmitting antenna. The receivingelectrode 105 b is used to receive an electric field transmitted after being induced in thehuman body 100 from thewearable computer 1 and thetransceiver 3′ that are mounted on other part of thehuman body 100 and thePC 5 and thetransceivers 3′a and 3′b, and is used as a receiving antenna. - The insulating
film 107 a is an insulator film disposed between the transmittingelectrode 105 a and thehuman body 100, and prevents the transmittingelectrode 105 a from directly contacting thehuman body 100. The insulatingfilm 107 b is an insulator film disposed between the receivingelectrode 105 b and thehuman body 100, and prevents the receivingelectrode 105 b from directly contacting thehuman body 100. - The electric
field sensor unit 110 that constitutes the electricfield sensor device 115 has a function of applying an electric field received by the receivingelectrode 105 b to the laser light, thereby changing the optical intensity of the laser light. - The
light receiving circuit 152 that constitutes the electricfield sensor device 115 has a function of receiving the laser light of which optical intensity is changed, converting the laser light into an electric signal, and performing signal processing such as amplification of this electric signal. Thesignal processing circuit 116 consists of at least a band pass filter. This band pass filter removes a frequency component other than a frequency component concerning reception information as an electric field to be detected among electric signals having various frequencies (that is, takes out only the frequency component concerning the reception information), thereby performing signal processing such as removal of noise from the electric signal. - The
waveform shaping circuit 117 shapes the waveform (signal processing) of an electric signal transmitted from thesignal processing circuit 116, and supplies the processed electric signal to thewearable computer 1 via the I/O circuit 101. - The electric
field sensor device 115 a according to the third embodiment as one example of the electricfield sensor device 115 is explained in detail with reference toFIG. 19 . The electricfield sensor device 115 a according to the present embodiment has an electricfield sensor unit 110 a as one example of the electricfield sensor unit 110, and alight receiving circuit 152 a as one example of thelight receiving circuit 152. The electricfield sensor device 115 a is provided in the transceivermain body 30 c as one example of the transceivermain body 30. - The electric
field sensor unit 110 a according to the present embodiment consists of thecurrent source 119, thelaser diode 121, thelens 133, abeam splitter 139, theoptical intensity modulator 124, and the first and thesecond lenses - The
optical intensity modulator 124 is configured to change the optical intensity of light that passes depending on the electric field intensity to be coupled. Thefirst electrode 125 and thesecond electrode 127 are provided on both side surfaces of theoptical intensity modulator 124, that are opposite in a vertical direction in the drawing. Thefirst electrode 125 and thesecond electrode 127 sandwich from both sides the proceeding direction of the laser light from thelaser diode 121 within theoptical intensity modulator 124, and can couple the electric field with the laser light at a right angle. - The electric
field sensor unit 110 a is connected to the receivingelectrode 105 b via thefirst electrode 125. Thesecond electrode 127 that is opposite to thefirst electrode 125 is connected to aground electrode 131, and functions as a ground electrode to thefirst electrode 125. The receivingelectrode 105 b detects an electric field that is transmitted after being induced in thehuman body 100, transmits this electric field to thefirst electrode 125, and can couple the electric field with theoptical intensity modulator 124 via thefirst electrode 125. - The laser light that is output from the
laser diode 121 based on the current control by thecurrent source 119 is made parallel light via thelens 133. The parallel laser light is incident to thebeam splitter 139. Thebeam splitter 139 is an optical system that branches the incident laser light into two laser lights and outputs the branched lights. A first laser light obtained by the branching by thebeam splitter 139 is incident to thefirst lens 141 a via theoptical intensity modulator 124. A second laser light obtained by the branching by thebeam splitter 139 is incident to thesecond lens 141 b not via theoptical intensity modulator 124. - The
light receiving circuit 152 a has a first set including thefirst photodiode 143 a that converts the first laser light into a current signal according to the optical intensity of the first laser light of which optical intensity is modulated by theoptical intensity modulator 124, the firstconstant voltage source 147 a that applies an inverse bias voltage to thefirst photodiode 143 a, and thefirst load resistor 145 a that converts the current signal obtained by conversion by thefirst photodiode 143 a into a voltage signal, and a second set including thesecond photodiode 143 b that converts the second laser light into a current signal according to the optical intensity of the second laser light received via thesecond lens 141 b, the secondconstant voltage source 147 b that applies an inverse bias voltage to thesecond photodiode 143 b, and thesecond load resistor 145 b that converts the current signal obtained by conversion by thesecond photodiode 143 b into a voltage signal. - With this arrangement, the
first photodiode 143 a receives the first laser light that passes through theoptical intensity modulator 124 and thefirst lens 141 a of the electricfield sensor unit 110 a, and the first set outputs a voltage signal (including a signal component) as a result. Thesecond photodiode 143 b receives the second laser light that passes through thesecond lens 141 b of the electricfield sensor unit 110 a, and the second set outputs a voltage signal (not including a signal component) containing noise of the laser light as a result. - The
light receiving circuit 152 a also has thedifferential amplifier 112 that differentially amplifies a voltage signal obtained by conversion by thefirst load resistor 145 a and a voltage signal obtained by conversion by thesecond load resistor 145 b. Thedifferential amplifier 112 differentially amplifies the voltage signals, and supplies the output to thesignal processing circuit 116 shown inFIG. 18 . - As explained above, according to the present embodiment, laser light is branched immediately before the laser light is incident to the
optical intensity modulator 124. One laser light is input to theoptical intensity modulator 124, and is used as laser light (including a signal component) for detecting an electric field. The other laser light is not input to theoptical intensity modulator 124, and is used as laser light (not including a signal component) for only removing noise from the laser light. Therefore, it is possible to remove noise from the laser light even when theoptical intensity modulator 124 is used that cannot differentially take out an intensity modulation signal unlike thepolarization modulator 123 that converts a polarization change of the laser light into an intensity change. - An electric
field sensor device 115 b, and the opticalintensity modulation transceiver 3 having the electricfield sensor device 115 b according to a fourth embodiment of the present invention are explained with reference toFIG. 20 . - The electric
field sensor device 115 b according to the present embodiment has the following electricfield sensor unit 110 b in place of the electricfield sensor unit 110 a of the electricfield sensor device 115 a according to the third embodiment. Constituent parts of the electricfield sensor unit 110 b that are identical with those of the electricfield sensor unit 110 a are assigned with the same reference numerals, and their explanation is omitted. Since thelight receiving circuit 152 a according to the present embodiment has the same configuration as that of thelight receiving circuit 152 a according to the first embodiment, explanation of thelight receiving circuit 152 a is omitted. - As shown in
FIG. 20 , the electricfield sensor unit 110 b according to the present embodiment has a first opticalvariable attenuator 134A inserted between thebeam splitter 139 and theoptical intensity modulator 124, and has a second opticalvariable attenuator 134B inserted between thebeam splitter 139 and thesecond lens 141 b. The first and the second opticalvariable attenuators - However, of the two laser lights obtained by branching by the
beam splitter 139, the first laser light passes through theoptical intensity modulator 124, but the second laser light does not pass through theoptical intensity modulator 124. Since transmission efficiency of the second laser light is higher than that of the first laser light, both transmission efficiencies need to be balanced. According to the present embodiment, attenuation of the second opticalvariable attenuator 134B through which the second laser light passes is set larger than attenuation of the first opticalvariable attenuator 134A through which the first laser light passes. - With this arrangement, the first optical
variable attenuator 134A attenuates the optical intensity of the first laser light obtained by branching by thebeam splitter 139, and then thefirst photodiode 143 a converts the first laser light into a current signal. The second opticalvariable attenuator 134B attenuates the optical intensity of the second laser light obtained by branching by thebeam splitter 139, and then thesecond photodiode 143 b converts the second laser light into a current signal. The attenuation of the laser light that passes through the first opticalvariable attenuator 134B is larger than the attenuation of the laser light that passes through the second opticalvariable attenuator 134A. - As explained above, according to the present embodiment, noise is removed from the laser light, by inserting the first and the second optical
variable attenuators differential amplifier 112 can be balanced even when the laser light is branched. - When the second optical
variable attenuator 134B by itself can balance input signals to thedifferential amplifier 112, the first opticalvariable attenuator 134A can be omitted. - An electric
field sensor device 115 c, and the opticalintensity modulation transceiver 3 having the electricfield sensor device 115 c according to a fifth embodiment of the present invention are explained with reference toFIG. 21 . - The electric
field sensor device 115 c according to the present embodiment has the followinglight receiving circuit 152 b in place of thelight receiving circuit 152 a of the electricfield sensor device 115 a according to the third embodiment. Constituent parts of thelight receiving circuit 152 b that are identical with those of thelight receiving circuit 152 a are assigned with the same reference numerals, and their explanation is omitted. Since the electricfield sensor unit 110 a according to the present embodiment has the same configuration as that of the electricfield sensor unit 110 a according to the first embodiment, explanation of the electricfield sensor unit 110 a is omitted. - As shown in
FIG. 21 , in place of the first and thesecond load resistors light receiving circuit 152 b according to the present embodiment has first and secondvariable load resistors variable load resistors variable load resistor 145B is set larger than that of the firstvariable load resistor 145A. - With this arrangement, voltage signals that are output from the
first photodiode 143 a and thesecond photodiode 143 b can have the same signal intensity. - As explained above, according to the present embodiment, in place of the first and the
second load resistors light receiving circuit 152 b has the first and the secondvariable load resistors differential amplifier 112 can be balanced even when the laser light is branched. - When input signals to the
differential amplifier 112 can be balanced using only one of the first and the secondvariable load resistors - An electric
field sensor device 115 d, and the opticalintensity modulation transceiver 3 having the electricfield sensor device 115 d according to a sixth embodiment of the present invention are explained with reference toFIG. 22 . - The electric
field sensor device 115 d according to the present embodiment has the followinglight receiving circuit 152 c in place of thelight receiving circuit 152 a of the electricfield sensor device 115 a according to the third embodiment. Constituent parts of thelight receiving circuit 152 c that are identical with those of thelight receiving circuit 152 a are assigned with the same reference numerals, and their explanation is omitted. Since the electricfield sensor unit 110 a according to the present embodiment has the same configuration as that of the electricfield sensor unit 110 a according to the first embodiment, explanation of the electricfield sensor unit 110 a is omitted. - As shown in
FIG. 22 , in place of the first and the secondconstant voltage sources light receiving circuit 152 c according to the present embodiment has first and secondvariable voltage sources variable voltage sources variable voltage source 147B is set smaller than that of the firstvariable voltage source 147A. - With this arrangement, voltage signals that are output from the
first photodiode 143 a and thesecond photodiode 143 b can have the same signal intensity. - As explained above, according to the present embodiment, in place of the first and the second
constant voltage sources light receiving circuit 152 c has the first and secondvariable voltage sources differential amplifier 112 can be balanced even when the laser light is branched. - When input signals to the
differential amplifier 112 can be balanced using only one of the first and the secondvariable voltage sources - An electric
field sensor device 115 e, and the opticalintensity modulation transceiver 3 having the electricfield sensor device 115 e according to a seventh embodiment of the present invention are explained with reference toFIG. 23 . - The electric
field sensor device 115 e according to the present embodiment has the followinglight receiving circuit 152 d in place of thelight receiving circuit 152 a of the electricfield sensor device 115 a according to the third embodiment. Constituent parts of thelight receiving circuit 152 d that are identical with those of thelight receiving circuit 152 a are assigned with the same reference numerals, and their explanation is omitted. Since the electricfield sensor unit 110 a according to the present embodiment has the same configuration as that of the electricfield sensor unit 110 a according to the first embodiment, explanation of the electricfield sensor unit 110 a is omitted. - As shown in
FIG. 23 , there are provided a first and a secondvariable gain amplifiers second photodiodes differential amplifier 112. The first and the secondvariable gain amplifiers variable gain amplifier 149B is set smaller than that of the firstvariable gain amplifier 149A. - With this arrangement, voltage signals that are output from the
first photodiode 143 a and thesecond photodiode 143 b can have the same signal intensity. - As explained above, according to the present embodiment, there are provided the first and the second
variable gain amplifiers second photodiodes differential amplifier 112, thereby removing noise from the laser light. Therefore, input signals to thedifferential amplifier 112 can be balanced even when the laser light is branched. - When input signals to the
differential amplifier 112 can be balanced using only one of the first and the secondvariable gain amplifiers - For the optical intensity modulators according to the third to the seventh embodiments, an electroabsorption (EA) optical intensity modulator, a Mach-Zehnder optical intensity modulator, and the like can be employed as in the conventional practice.
- A transceiver
main body 30 d of a transceiver according to an eighth embodiment of the present invention is explained with reference toFIG. 24 . - The transceiver
main body 30 d according to the present embodiment has an overall configuration as shown inFIG. 24 . The transceivermain body 30 d excluding an electricfield sensor device 215, anoise detector 218, and acontrol signal generator 219 has the same configuration as that of the transceivermain body 30 c according to the third embodiment, and therefore, identical parts are assigned with the same reference numerals and their explanation is omitted. - The transceiver
main body 30 d according to the present embodiment uses any one of the electricfield sensor devices 115 b to 115 e according to the fourth to the seventh embodiments, for the electricfield sensor device 215. The transceivermain body 30 d includes thenoise detector 218 that detects a magnitude of noise of a voltage signal output from thesignal processing circuit 116, and thecontrol signal generator 219 that generates a control signal to variably control variable values of the electricfield sensor unit 110 and thelight receiving circuit 152 that constitute the electricfield sensor device 215, based on detection data output from thenoise detector 218. Thenoise detector 218 detects a level of noise that remains in the electric signal output from thesignal processing circuit 116, that is, a level of noise that is present in a frequency band concerning reception information as an electric field to be detected. - The “variable value” means the following in respective embodiments. According to the fourth embodiment (
FIG. 20 ), the variable value means attenuation of the optical intensity of the first and the second opticalvariable attenuators FIG. 21 ), the variable value means resistance of the first and the secondvariable load resistors FIG. 22 ), the variable value means a voltage of the first and the secondvariable voltage sources FIG. 23 ), the variable value means a voltage gain of the first and the second variable gain amplifiers 113A and 113B. - As explained above, according to the present embodiment, there is an effect that, even after the transceiver
main body 30 d is manufactured, a variable value can be automatically changed and adjusted. - Next, an embodiment of a transceiver is explained, the transceiver including a transceiver main body that can transmit and receive information via an electric field transmission medium, a battery that drives the transceiver main body, and an insulating case that covers the transceiver main body, and the transceiver being of a type that a human body (hand) as the electric field transmission medium contacts a wide surface of an external wall surface.
- The main point of the embodiment of the transceiver is explained first. Regarding the transceiver and the wearable computer shown in
FIG. 9 , the equivalent circuit between the human body (hand), the transmitting and receiving electrode, the transceiver main body, and the battery is considered. -
FIG. 25 is a diagram showing an equivalent circuit between a human body, a transmitting and receiving electrode, and a transceiver main body. - In
FIG. 9 , thehuman body 100 and the transmitting and receivingelectrode 105′ are separated by the insulatingfilm 107′. Therefore, impedance between thehuman body 100 and the transmitting and receivingelectrode 105 can be expressed by the equivalent circuit as shown inFIG. 25 . - In order to realize highly reliable communications via the
human body 100, an induced alternate current electric field (frequency f) to thehuman body 100 needs to be large. In order to increase the induced alternate current electric field (frequency f), the impedance between thehuman body 100 and the transmitting and receivingelectrode 105 needs to be small. As shown inFIG. 25 , a resistance component of the impedance between thehuman body 100 and the transmitting and receivingelectrode 105 is considered very large. Therefore, in order to make the impedance small, the capacitance component needs to be set large. - In order to increase the capacitance component, it is effective to use a material having a large dielectric constant for the insulating
film 107 or decrease the thickness of the insulatingfilm 107. It is also effective to have a large area of the transmitting and receivingelectrode 105 to indirectly face the human body over a wide range. - However, when the insulating
film 107 is too thin, there is a high possibility that thehuman body 100 directly touches the transmitting and receivingelectrode 105, and a risk that a large current flows to thehuman body 100 increases. Therefore, when the area of the transmitting and receivingelectrode 105 is increased, the capacitance can be increased while securing safety, which is preferable. When the transmitting and receivingelectrode 105 is made large, a shielding effect can be expected. -
FIG. 26 is a diagram showing an equivalent circuit between a human body, a transceiver main body, and a battery. - In order to realize highly reliable communications via the
human body 100, it is necessary to avoid inducing an unnecessary alternate current electric field (frequency f) between thehuman body 100, the transceivermain body 30, and thebattery 6. For this purpose, impedance between these items needs to be increased, thereby decreasing mutual coupling capacitance. - When an insulator is interposed between the items, and in order to increase this effect, it is necessary to use an insulator having a small dielectric constant, or decrease an area of contact between the insulator, the
human body 100, the transceivermain body 30, and thebattery 6, or increase the thickness of the insulator. - From the above viewpoint, the following embodiment is considered to carry out secure and highly reliable communications via the human body in the transceiver shown in
FIG. 9 . - A ninth embodiment is explained below with reference to
FIG. 27 toFIG. 30 . -
FIG. 27 is an overall configuration diagram of atransceiver 3 a and thewearable computer 1 according to a ninth embodiment of the present invention.FIG. 28 is a functional block diagram showing mainly a function of the transceivermain body 30.FIG. 29 is a detailed configuration diagram of an electricfield sensor device 115′.FIG. 30 is an image diagram showing a using state of thetransceiver 3 a and thewearable computer 1 shown inFIG. 27 . - As shown in
FIG. 27 , thetransceiver 3 a consists of the insulatingcase 33 formed with an insulator, a device incorporated in the insulatingcase 33, and the following members attached to the outside of the insulatingcase 33. - An insulating
foam member 7 a that weakens electric coupling between the insulatingcase 33 and the transceivermain body 30 is attached to the bottom of the internal wall surface of the insulatingcase 33. The transceivermain body 30 that carries out transmission and reception of data (information) to and from thewearable computer 1 is attached to the upper surface of the insulatingfoam member 7 a. An insulatingfoam member 7 b that weakens electric coupling between the transceivermain body 30 and thebattery 6 is attached to the upper surface of the transceivermain body 30. Thebattery 6 that drives thetransceiver 30 is attached to the upper surface of the insulatingfoam member 7 b. In other words, the insulatingfoam member 7 a is sandwiched (supported in a sandwiched state) between the insulatingcase 33 and the transceivermain body 30, and the insulatingfoam member 7 b is sandwiched between the transceivermain body 30 and thebattery 6. The insulatingfoam members foam member 7 a can restrict transmission of noise between the insulatingcase 33 and the transceivermain body 30. The insulatingfoam member 7 b can restrict transmission of noise between the transceivermain body 30 and thebattery 6. - A
first ground electrode 131 described later is extended from the transceivermain body 30, and is attached to an upper part of the internal wall surface of the insulatingcase 33 apart from the transmitting and receivingelectrode 105 in a state that thefirst ground electrode 131 is not in contact with other devices (such as thebattery 6, and the wearable computer 1). Asecond ground electrode 161 and athird ground electrode 163 described later are extended from the transceivermain body 30, and are attached to an upper part of the internal wall surface of the insulatingcase 33 apart from the transmitting and receivingelectrode 105 in a state that these ground electrodes are not in contact with other devices (such as thebattery 6, and the wearable computer 1) and thefirst ground electrode 131. - The transmitting and receiving
electrode 105 is attached to the bottom of the external wall surface and the side of the external wall surface of the insulatingcase 33, thereby covering the whole of the transmitting and receivingelectrode 105 with the insulatingfilm 107. Parts other than the operation/input surface of thewearable computer 1 are covered with the insulatingcase 11. - The transceiver
main body 30 is similar to the conventional transceivermain body 30′ in that the transceivermain body 30 has the I/O (input/output)circuit 101, thetransmitter 103, the transmitting and receivingelectrode 105, the insulatingfilm 107, the electricfield sensor device 115′, and the receiving circuit 113 (thesignal processing circuit 116, and the waveform shaping circuit 117). These configurations are explained below. - The I/
O circuit 101 is used for the transceivermain body 30 to input and output information (data) to and from an external device such as thewearable computer 1. Thetransmitter 103 consists of a transmitter circuit that induces, based on the information (data) output from the I/O circuit 101, an electric field concerning this information in thehuman body 100. The transmitting and receivingelectrode 105 is used for thetransmitter 103 to induce an electric field in thehuman body 100, and is used as a transmitting antenna. The transmitting and receivingelectrode 105 is also used to receive an electric field transmitted after being induced in thehuman body 100, and is used as a receiving antenna. The insulatingfilm 107 is an insulator film disposed between the transmitting and receivingelectrode 105 and thehuman body 100, thereby preventing the transmitting and receivingelectrode 105 from directly contacting thehuman body 100. - The electric
field sensor device 115′ has a function of detecting an electric field received by the transmitting and receivingelectrode 105, and converting this electric field into an electric signal as reception information. - The
signal processing circuit 116 of the receivingcircuit 113 amplifies an electric signal transmitted from the electricfield sensor unit 115′, limits the band of the electric signal, and removes unnecessary noise and an unnecessary signal component. - The
waveform shaping circuit 117 shapes the waveform (signal processing) of an electric signal transmitted from thesignal processing circuit 116, and supplies the processed electric signal to thewearable computer 1 via the I/O circuit 101. Thetransmitter 103, the receivingcircuit 113, and the I/O circuit 101 can be driven with thebattery 6. - The electric
field sensor unit 115′ is explained in detail with reference toFIG. 29 . This is explained again although the outline is already explained with reference toFIG. 4 . - The electric
field sensor unit 115′ restores the electric field received by the transceivermain body 30 to the electric signal. This processing is carried out by detecting the electric field according to an electro-optic method using laser light and an electro-optic crystal. - As shown in
FIG. 29 , the electricfield sensor unit 115′ consists of thecurrent source 119, thelaser diode 121, the electro-optic element (electro-optic crystal) 123, the first and thesecond wave plates polarizing beam splitter 139, theplural lenses photodiode first ground electrode 131. - Of the above, the electro-
optic element 123 has sensitivity in only the electric field that is coupled in a direction perpendicular to a proceeding direction of laser light that is emitted from thelaser diode 121. The electro-optic element 123 changes optical characteristic, that is, a birefringence index, according to the electric field intensity, and changes the polarization of the laser light based on the change of the birefringence index. Thefirst electrode 125 and thesecond electrode 127 are provided on both side surfaces of the electro-optic element 123, that are opposite in a vertical direction inFIG. 29 . Thefirst electrode 125 and thesecond electrode 127 sandwich the proceeding direction of the laser light from thelaser diode 121 in the electro-optic element 123, and can couple the electric field with the laser light at a right angle. - The electric
field sensor unit 115′ is connected to the transmitting and receivingelectrode 105 via thefirst electrode 125. Thesecond electrode 127 that is opposite to thefirst electrode 125 is connected to thefirst ground electrode 131, and functions as a ground electrode to thefirst electrode 125. The transmitting and receivingelectrode 105 receives an electric field that is transmitted after being induced in thehuman body 100, transmits this electric field to thefirst electrode 125, and can couple the electric field with the electro-optic element 123 via thefirst electrode 125. - On the other hand, the laser light output from the
laser diode 121 according to the current control from thecurrent source 119 is made parallel light via thelens 133. Thefirst wave plate 135 adjusts the polarization state of the parallel laser light, and inputs the laser light to the electro-optic element 123. The laser light that is incident to the electro-optic element 123 is propagated between the first and thesecond electrodes optic element 123. During the propagation of the laser light, the transmitting and receivingelectrode 105 receives the electric field that is transmitted after being induced in thehuman body 100 as explained above, and couples this electric field with the electro-optic element 123 via thefirst electrode 125. Then, the electric field is formed from thefirst electrode 125 toward thesecond electrode 127 connected to theground electrode 131. Since the electric field is perpendicular to the proceeding direction of the laser light that is incident from thelaser diode 121 to the electro-optic element 123, the birefringence index as the optical characteristic of the electro-optic element 123 changes, and the polarization of the laser light changes accordingly. - The
second wave plate 137 adjusts the polarization state of the laser light of which polarization is changed by the electric field from thefirst electrode 125 in the electro-optic element 123, and inputs the laser light to thepolarizing beam splitter 139. Thepolarizing beam splitter 139 separates the laser light incident from thesecond wave plate 137, into a P wave and an S wave, and converts the laser light into optical intensity change. - The first and the
second lenses polarizing beam splitter 139. The first and thesecond photodiodes second photodiodes signal processing circuit 116 shown inFIG. 28 performs signal processing of amplification of the voltage signals and removal of noise. - According to the transceiver
main body 30 of the present embodiment, thefirst ground electrode 131 that becomes a reference point of voltage for the electricfield sensor unit 115′ is extended to the outside of the transceivermain body 30 as shown inFIG. 27 . Thesecond ground electrode 161 that becomes a reference point of voltage for thesignal processing circuit 116 and thethird ground electrode 163 that becomes a reference point of voltage for thetransmitter 103 are extended in common to the outside. - A using state of the
transceiver 3 a and thewearable computer 1 according to the present embodiment is explained next with reference toFIG. 30 . - As shown in
FIG. 30 , when the human hand (human body 100) holds thetransceiver 3 a, the hand holds the bottom of the external wall surface and the side of the external wall surface of the insulatingcase 33. In this case, the transmitting and receivingelectrode 105 and the insulatingfilm 107 cover not only the bottom of the external wall surface but also the side of the external wall surface of the insulatingcase 33. Therefore, although transmission electric fields E1, E2, and E3 are induced from the whole of the insulatingcase 33, return of a part of the electric fields from the hand to thetransceiver 3 via the side surface of the insulatingcase 33 is restricted. - As explained above, according to the present embodiment, the transmitting electrode (the transmitting and receiving
electrode 105, in this case) is attached to a wide surface, including not only the bottom surface (bottom) but also the side surface (side) and the like, of the external wall surface of the insulatingcase 33, and is covered with the insulatingfilm 107. Therefore, even when the human hand holds thetransceiver 3 a, it is possible to prevent a part of the transmission electric fields returning from the hand back to thetransceiver 3 a. - Further, because the
first ground electrode 131, thesecond ground electrode 161, and thethird ground electrode 163 are attached to the upper parts of the internal wall surface of the insulatingcase 33 apart from the transmitting and receivingelectrode 105, it is possible to prevent leakage of an unnecessary signal from the transmitting and receivingelectrode 105 to the transceivermain body 30, and the ground can be reinforced. - Further, because the insulating
foam member 7 a is sandwiched between the insulatingcase 33 and the transceivermain body 30, and the insulatingfoam member 7 b is sandwiched between the transceivermain body 30 and thebattery 6, it is possible to restrict noise from entering the transceivermain body 30 from thebattery 6 and the insulatingcase 33. - A tenth embodiment is explained below with reference to
FIG. 31 . -
FIG. 31 is an overall configuration diagram of a transceiver 32 and thewearable computer 1 according to the tenth embodiment. Constituent parts according to the tenth embodiment identical with those according to the ninth embodiment are assigned with the same reference numerals, and their explanation is omitted. - According to the present embodiment, as shown in
FIG. 31 , insulatingpillars foam members - According to the present embodiment, contact areas between the insulator, the
human body 100, the transceivermain body 30, and thebattery 6 are made small, respectively. Therefore, there is a further significant effect that an unnecessary alternate current field is not induced. - Wooden materials other than the foamed materials may be used for the insulating
pillars - While pillars are employed in the present embodiment, a block structure may be also employed.
- An eleventh embodiment is explained below with reference to
FIG. 32 . -
FIG. 32 is an overall configuration diagram of atransceiver 3 c and thewearable computer 1 according to the eleventh embodiment. - According to the present embodiment, as shown in
FIG. 32 , the second and thethird ground electrodes case 33 of thetransceiver 3 c, and are attached to the side surface (side) of the insulatingcase 11 of thewearable computer 1. - As explained above, according to the present embodiment, in addition to the effect of the ninth embodiment, the second and the
third ground electrodes electrode 105 than that according to the ninth embodiment. Therefore, leakage of an unnecessary signal from the transmitting and receivingelectrode 105 to the transceivermain body 30 can be prevented more securely, and the ground can be further reinforced. - A twelfth embodiment is explained below with reference to
FIG. 33 . -
FIG. 33 is an overall configuration diagram of atransceiver 3 d and thewearable computer 1 according to the twelfth embodiment. Constituent parts according to the twelfth embodiment identical with those according to the ninth embodiment are assigned with the same reference numerals, and their explanation is omitted. - According to the present embodiment, as shown in
FIG. 33 , thefirst ground electrode 131 is extended from the insulatingcase 33 of thetransceiver 3 d, and is attached to the side surface (side) of the insulatingcase 11 of thewearable computer 1. - As explained above, according to the present embodiment, in addition to the effect of the ninth embodiment, the
first ground electrode 131 is positioned farther from the transmitting and receivingelectrode 105 than that according to the ninth embodiment. Therefore, leakage of an unnecessary signal from the transmitting and receivingelectrode 105 to the transceivermain body 30 can be prevented more securely, and the ground can be further reinforced. - A thirteenth embodiment is explained below with reference to
FIG. 34 . -
FIG. 34 is an overall configuration diagram of atransceiver 3 e and thewearable computer 1 according to the thirteenth embodiment. Constituent parts according to the thirteenth embodiment identical with those according to the ninth embodiment are assigned with the same reference numerals, and their explanation is omitted. - According to the present embodiment, as shown in
FIG. 34 , the transmitting and receivingelectrode 105 is divided into a transmittingelectrode 105 a exclusively used for transmission and a receivingelectrode 105 b exclusively used for reception. The transmittingelectrode 105 a is disposed at a position corresponding to the transmitting and receivingelectrode 105 shown inFIG. 31 . The receivingelectrode 105 b is disposed on an external bottom surface of the insulatingfilm 107 a as shown inFIG. 34 . The receivingelectrode 105 b is also covered with the insulatingfilm 107 b to prevent the human body from being in direct contact with the receivingelectrode 105 b. According to the present embodiment, the insulatingfilm 107 shown inFIG. 31 is expressed as the insulatingfilm 107 a. - As explained above, according to the present embodiment, the transmitting
electrode 105 a is relatively large, and covers substantially the whole of the insulatingcase 33, and the receivingelectrode 105 b is small. Therefore, in addition to the effect of the ninth embodiment, there is an effect that a rate of returning of a part of the electric fields for transmission from the hand is small. - The layout positions of the transmitting
electrode 105 a and the receivingelectrode 105 b may be replaced, like atransceiver 3 f shown inFIG. 35 (a fourteenth embodiment). - According to the eleventh and the twelfth embodiments, one ground electrode is attached to the side surface of the insulating
case 11 of thewearable computer 1. However, the attaching mode is not limited to this. Thefirst ground electrode 131, and the second andthird ground electrodes case 11 of thewearable computer 1, without thefirst ground electrode 131 contacted with the second andthird ground electrodes - According to the ninth and the eleventh to the thirteenth embodiments, the insulating
foam member 7 a is sandwiched between the insulatingcase 33 and the transceivermain body 30, and the insulatingfoam member 7 b is sandwiched between the transceivermain body 30 and thebattery 6. The layout is not limited to this. As shown inFIG. 36 , an integrated insulatingfoam member 8 that covers both thebattery 6 and the transceivermain body 30 without these members contacted with each other can be used. Further, as shown inFIG. 37 , acushion insulating member 9 in which gas like air is confined can be used instead of the foam member. - As explained above, according to the present invention, there is an effect that when an electric field transmission medium like a human body touches a position in a two-dimensional space, information can be easily input to the
wearable computer 1 and the like via the electric field transmission medium. - Further, according to the present invention, laser light is branched (separated) before the laser light is incident to optical intensity modulating means. One laser light is input to the optical intensity modulating means, and is used as laser light for detecting an electric field. The other laser light is not input to the optical intensity modulating means, but is used as laser light for only removing noise from the laser light. Therefore, there is an effect that it is possible to remove noise from the laser light even when the optical intensity modulating means is used that cannot differentially take out an intensity modulation signal like the modulator that converts a polarization change of the laser light into an intensity change.
- Further, according to the present invention, the transmitting electrode is attached to a wide surface, including not only the bottom surface (bottom) but also the side surface (side), of the external wall surface of the insulating case. Therefore, even when the human hand holds the transceiver, it is possible to prevent a part of the transmission electric fields returning from the hand back to the transceiver.
Claims (9)
1. An information input system comprising:
electric field inducing means that is contacted or operated by an electric field transmission medium, and induces an electric field in said electric field transmission medium according to a physical quantity based on the contact or operation;
a transceiver that receives the electric field induced in said electric field transmission medium, applies the electric field to a polarization modulator or an optical intensity modulator, polarization-modulates or optical intensity-modulates laser light according to the electric field, converts the polarization-modulated or optical intensity-modulated laser light into an electric signal, extracts an electric signal having a frequency component concerning a physical quantity based on said contact or operation from the converted electric signals, and outputs the electric signal concerning the physical quantity based on said contact or operation; and
information processing means for inputting therein the electric signal concerning the physical quantity based on said contact or operation from said transceiver, and obtaining information corresponding to the physical quantity based on said contact or operation by said electric field transmission medium.
2. An electric field sensor device that modulates optical intensity of laser light based on an electric field to be detected, thereby detecting said electric field, said electric field sensor device having an electric field sensor unit and a light receiving circuit, wherein said electric field sensor unit includes:
laser light emitting means;
branching means for branching a laser light emitted from said laser light emitting means into a first laser light and a second laser light that are different from each other; and
optical intensity modulating means with which said electric field to be detected is coupled, that modulates the optical intensity of said first laser light based on said coupled electric field, and
said light receiving circuit includes:
first light/voltage converting means for converting the optical intensity of said first laser light modulated by said optical intensity modulating means into a voltage signal;
second light/voltage converting means for converting the optical intensity of said second laser light branched by said branching means into a voltage signal; and
differential amplifying means for differentially amplifying the voltage signal obtained by conversion by said first light/voltage converting means and the voltage signal obtained by conversion by said second light/voltage converting means.
3. The electric field sensor device according to claim 2 , wherein said electric field sensor unit further includes an optical variable attenuator that attenuates the optical intensity of said second laser light obtained by branching by said branching means, and said second photoelectrical converting means inputs said second laser light attenuated by said optical variable attenuator.
4. The electric field sensor device according to claim 2 , wherein said electric field sensor unit further includes a first optical variable attenuator that attenuates the optical intensity of said first laser light obtained by branching by said branching means at a predetermined rate, and a second optical variable attenuator that attenuates the optical intensity of said second laser light obtained by branching by said branching means at a rate higher than an attenuation rate of said first optical variable attenuator, said optical intensity modulating means inputs therein said first laser light attenuated by said first optical variable attenuator, and said second photoelectrical converting means inputs therein said second laser light attenuated by said second optical variable attenuator.
5. The electric field sensor device according to claim 2 , wherein
said first light/voltage converting means includes:
first light/current converting means for converting the optical intensity of said first laser light modulated by said optical intensity modulating means into a current signal;
a first voltage source that applies an inverse bias voltage to said first light/current converting means; and
a first load resistor that converts said current signal obtained by conversion by said first light/current converting means into a voltage signal, and
said second light/voltage converting means includes:
second light/current converting means for converting the intensity of said second laser light obtained by branching by said branching means into a current signal;
a second voltage source that applies an inverse bias voltage to said second light/current converting means; and
a second load resistor that converts said current signal obtained by conversion by said second light/current converting means into a voltage signal.
6. The electric field sensor device according to claim 5 , wherein at least one of said first load resistor and said second load resistor is a variable resistor.
7. The electric field sensor device according to claim 5 , wherein at least one of said first voltage source and said second voltage source is a variable voltage source.
8. The electric field sensor device according to claim 2 , wherein said light receiving circuit further includes amplifying means for amplifying at least one of the voltage signal obtained by conversion by said first light/voltage converting means and the voltage signal obtained by conversion by said second light/voltage converting means.
9. A transceiver that receives information based on an electric field induced in an electric field transmission medium, thereby receiving the information via said electric field transmission medium, said transceiver comprising:
said electric field sensor device according to claim 2 ;
a signal processing circuit that at least removes a noise from a voltage signal output from said electric field sensor device;
noise detecting means for detecting quantity of a noise component of the voltage signal output from said signal processing circuit; and
a control signal generator that generates a control signal to variably control a variable value of said electric field sensor unit or said light receiving circuit based on the detection data output from said noise detecting means.
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US12/111,866 US20080205904A1 (en) | 2003-06-30 | 2008-04-29 | Electric Field Sensor Device, Transceiver, Positional Information Obtaining System, and Information Input System |
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PCT/JP2004/009159 WO2005002096A1 (en) | 2003-06-30 | 2004-06-29 | Electric field-detecting optical device, tranceiver, positional information-acquiring system, and information input system |
US12/111,866 US20080205904A1 (en) | 2003-06-30 | 2008-04-29 | Electric Field Sensor Device, Transceiver, Positional Information Obtaining System, and Information Input System |
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PCT/JP2004/009159 Division WO2005002096A1 (en) | 2003-06-30 | 2004-06-29 | Electric field-detecting optical device, tranceiver, positional information-acquiring system, and information input system |
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US7907895B2 (en) * | 2003-06-30 | 2011-03-15 | Nippon Telegraph And Telephone Corporation | Electric field sensor device, transceiver, positional information obtaining system and information input system |
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US8606177B2 (en) * | 2007-05-02 | 2013-12-10 | Samsung Electronics Co., Ltd. | Apparatus and method for controlling human body contact of ground electrode, and human body communication system using the same |
US20140062927A1 (en) * | 2012-01-31 | 2014-03-06 | Panasonic Corporation | Haptic feedback device and haptic feedback method |
US9292090B2 (en) * | 2012-01-31 | 2016-03-22 | Panasonic Intellectual Property Management Co., Ltd. | Haptic feedback device and haptic feedback method |
US20160283030A1 (en) * | 2015-03-27 | 2016-09-29 | Samsung Electronics Co., Ltd. | Electronic Device, Wearable Device and Controlling Method Thereof |
US20180006734A1 (en) * | 2016-07-04 | 2018-01-04 | Electronics And Telecommunications Research Institute | Reception device and transmission/reception system including the same |
US10044449B2 (en) * | 2016-07-04 | 2018-08-07 | Electronics And Telecommunications Research Institute | Reception device and transmission/reception system including the same |
CN112505438A (en) * | 2020-11-26 | 2021-03-16 | 清华大学 | Miniature electric field sensing device based on electrostatic force and piezoresistive effect |
Also Published As
Publication number | Publication date |
---|---|
KR100777765B1 (en) | 2007-11-20 |
KR20060127419A (en) | 2006-12-12 |
KR100761443B1 (en) | 2007-09-27 |
DE602004012832D1 (en) | 2008-05-15 |
EP1564917A1 (en) | 2005-08-17 |
US7907895B2 (en) | 2011-03-15 |
US20050244166A1 (en) | 2005-11-03 |
CN102170313A (en) | 2011-08-31 |
CN1701544B (en) | 2011-05-18 |
KR20060127420A (en) | 2006-12-12 |
JPWO2005002096A1 (en) | 2006-08-10 |
JP3974628B2 (en) | 2007-09-12 |
CN1701544A (en) | 2005-11-23 |
KR20060020598A (en) | 2006-03-06 |
EP1564917A4 (en) | 2006-12-20 |
KR100761442B1 (en) | 2007-09-27 |
EP1564917B1 (en) | 2008-04-02 |
WO2005002096A1 (en) | 2005-01-06 |
DE602004012832T2 (en) | 2009-05-07 |
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