WO1996007981A1 - Object position detector - Google Patents
Object position detector Download PDFInfo
- Publication number
- WO1996007981A1 WO1996007981A1 PCT/US1995/011180 US9511180W WO9607981A1 WO 1996007981 A1 WO1996007981 A1 WO 1996007981A1 US 9511180 W US9511180 W US 9511180W WO 9607981 A1 WO9607981 A1 WO 9607981A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- die
- digital signals
- sum
- capacitance
- sensor
- Prior art date
Links
Classifications
-
- 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
- G06F1/1626—Constructional details or arrangements for portable computers with a single-body enclosure integrating a flat display, e.g. Personal Digital Assistants [PDAs]
-
- 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
- G06F3/033—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor
- G06F3/0354—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor with detection of 2D relative movements between the device, or an operating part thereof, and a plane or surface, e.g. 2D mice, trackballs, pens or pucks
- G06F3/03547—Touch pads, in which fingers can move on a surface
-
- 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
-
- 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
- G06F3/0416—Control or interface arrangements specially adapted for digitisers
- G06F3/04166—Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving
-
- 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
- G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means
- G06F3/0445—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
-
- 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
- G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means
- G06F3/0446—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
Definitions
- the present invention relates to object position sensing transducers and systems. More particularly, the present invention relates to object position recognition useful in applications such as cursor movement for computing devices and other applications.
- a mouse While extremely popular as a position indicating device, a mouse has mechanical parts and requires a surface upon which to roll its position ball. Furthermore, a mouse usually needs to be moved over long distances for reasonable resolution. Finally, a mouse requires the user to lift a hand from the keyboard to make the cursor movement, thereby upsetting the prime purpose, which is usually typing on the computer.
- Trackball devices are similar to mouse devices. A major difference, however is that, unlike a mouse device, a trackball device does not require a surface across which it must be rolled. Trackball devices are still expensive, have moving parts, and require a relatively heavy touch as do the mouse devices. They are also large in size and doe not fit well in a volume- sensitive application like a laptop computer. There are several available touch-sense technologies which may be employed for use as a position indicator. Resistive-membrane position sensors are known and used in several applications. However, they generally suffer from poor resolution, the sensor surface is exposed to the user and is thus subject to wear. In addition, resistive-membrane touch sensors are relatively expensive. A one-surface approach requires a user to be grounded to the sensor for reliable operation. This cannot be guaranteed in portable computers. An example of a one-surface approach is the UnMouse product by MicroTouch, of Wilmington, MA A two-surface approach has poorer resolution and potentially will wear out very quickly in time.
- Resistive tablets are taught by United States Patent No. 4,680,430 to Yoshikawa, United States Patent No. 3,497,617 to Ellis and many others.
- the drawback of all such approaches is the high power consumption and the high cost of the resistive membrane employed.
- SAW Surface Acoustic Wave
- Strain gauge or pressure plate approaches are an interesting position sensing technology, but suffer from several drawbacks.
- This approach may employ piezo-electric transducers.
- One drawback is that the piezo phenomena is an AC phenomena and may be sensitive to the user's rate of movement.
- strain gauge or pressure plate approaches are somewhat expensive because special sensors are required.
- Optical approaches are also possible but are somewhat limited for several reasons. All would require light generation which will require external components and increase cost and power drain. For example, a "finger-breaking" infra-red matrix position detector consumes high power and suffers from relatively poor resolution.
- Desirable attributes of such a device are low power, low profile, high resolution, low cost, fast response, and ability to operate reliably when the finger carries electrical noise, or when the touch surface is contaminated with dirt or moisture.
- United States Patent No. 4,550,221 to Mabusth teaches a capacitive tablet wherein the effective capacitance to "virtual ground" is measured by an oscillating signal. Each row or column is polled sequentially, and a rudimentary form of interpolation is applied to resolve the position between two rows or columns. An attempt is made to address the problem of electrical interference by averaging over many cycles of the oscillating waveform. The problem of contamination is addressed by sensing when no finger was present, and applying a periodic calibration during such no-finger-present periods.
- United States Patent No. 4,639,720 to Rympalski teaches a tablet for sensing the position of a stylus.
- the stylus alters the transcapacitance coupling between row and column electrodes, which are scanned sequentially.
- United States Patent No. 4,736,191 to Matzke teaches a radial electrode arrangement under the space bar of a keyboard, to be activated by touching with a thumb. This patent teaches the use of total touch capacitance, as an indication of the touch pressure, to control the velocity of cursor motion. Pulsed sequential polling is employed to address the effects of electrical interference.
- United States Patent No. 4,733,222 to Evans is the first to teach a capacitance touch measurement system that interpolates to a high degree.
- Evans teaches a three terminal measurement system that uses a drive, sense and electrode signal set (3 signals) in its matrix, and bases the measurement on die attenuation effect of a finger on d e electrode node signal (uses a capacitive divider phenomena).
- Evans sequentially scans through each drive set to measure the capacitance. From the three largest responses an interpolation routine is applied to determine finger position.
- Evans also teaches a zeroing technique tiiat allows "no-finger" levels to be cancelled out as part of the measurement.
- United States Patent No. 5,016,008 to Gruaz describes a touch sensitive pad that also uses interpolation.
- Gruaz uses a drive and sense signal set (2 signals) in d e touch matrix and like Evans relies on the attenuation effect of a finger to modulate the drive signal.
- the touch matrix is sequentially scanned to read the response of each matrix line.
- An interpolation program selects the two largest adjacent signals in both dimensions to determine the finger location, and ratiometrically determines the effective position from those 4 numbers.
- Gerpheide PCT application US90/04584, publication No. W091/03039, United States Patent No. 5,305,017 applies to a touch pad system a variation of die virtual dipole approach of Greanias.
- Gerpheide teaches die application of an oscillating potential of a given frequency and phase to all electrodes on one side of the virtual dipole,and an oscillating potential of the same frequency and opposite phase to those on the other side.
- Electronic circuits develop a "balance signal" which is zero when no finger is present, and which has one polarity if a finger is on one side of die center of the virtual dipole, and the opposite polarity if die finger is on die opposite side.
- the virtual dipole is scanned sequentially across the tablet. Once the finger is located, it is "tracked” by moving die virtua dipole toward die finger once the finger has moved more than one row or column.
- the virtual dipole method operates by generating a balance signal that is zero when die capacitance does not vary with distance, it only senses the perimeter of d e finge contact area, rather than the entire contact area. Because d e method relies on synchronous detection of die exciting signal, it must average for long periods to reject electrical interference, an hence it is slow. The averaging time required by this method, together with die necessity to search sequentially for a new finger contact once a previous contact is lost, makes this method, like tiios before it, fall short of the requirements for a fast pointing device mat is not affected by electrical interference.
- Yet another object of the present invention is to provide a two-dimensional capacitive sensing system equipped with a separate set of drive sense electronics for each row and for each column of a capacitive tablet, wherein all row electrodes are sensed simultaneously, and all column electrodes are sensed simultaneously and wherein die information defining the location of a finger or other conductive object is processed in digital form.
- the present invention uses adaptive analo techniques to overcome offset and scale differences between channels, and can thus sense eithe transcapacitance or self-capacitance of all tablet rows or columns in parallel.
- This parallel-sensin capability made possible by providing one set of electronics per row or column, allows th sensing cycle to be extremely short, thus allowing fast response while still maintaining immunit to very high levels of electrical interference.
- the present invention comprises a position-sensing technology particularly usefu for applications where finger position information is needed, such as in computer "mouse" o trackball environments.
- the position-sensing technology of the present invention has much more general application than a computer mouse, because its sensor can detect and report i one or more points are being touched.
- the detector can sense the pressure of die touch.
- a position sensing system includes a position sensing transduce comprising a touch-sensitive surface disposed on a substrate, such as a printed circuit board, including a matrix of conductive lines.
- a first set of conductive lines runs in a first direction and i insulated from a second set of conductive lines running in a second direction generally perpendicular to die first direction.
- An insulating layer is disposed over the first and second set of conductive lines. The insulating layer is thin enough to promote significant capacitive coupling between a finger placed on its surface and the first and second sets of conductive lines.
- Sensing electronics respond to die proximity of a finger, conductive object, or an object of high dielectric constant (i.e., greater than about 5) to translate die capacitance changes o die conductors caused by object proximity into digital information which is processed to derive position and touch pressure information. Its output is a simple X, Y and pressure value of the one object on its surface.
- fingers are to be considered interchangable with conductive objects and objects of high dielectric constant.
- Parallel drive/sense techniques according to die present invention allow input samples to be taken simultaneously, thus all channels are affected by the same phase of an interfering electrical signal, gready simplifying the signal processing and noise filtering.
- the voltages on all of die X lines of the sensor matrix are simultaneously moved, while die voltages of the Y lines are held at a constant voltage, with the complete set of sampled points simultaneously giving a profile of the finger in the X dimension.
- d e voltages on all of the Y lines of the sensor matrix are simultaneously moved, while die voltages of die X lines are held at a constant voltage to obtain a complete set of sampled points simultaneously giving a profile of the finger in the other dimension.
- a second drive/sense method die voltages on all of die X lines of die sensor matrix are simultaneously moved in a positive direction, while the voltages of die Y lines are moved in a negative direction.
- the voltages on all of d e X lines of the sensor matrix are simultaneously moved in a negative direction, while the voltages of the Y lines are moved in a positive direction.
- Both embodiments then take these profiles and derive a digital value representing die centroid for X and Y position and derive a second digital value for the Z pressure information.
- the digital information may be direcdy used by a host computer.
- the position sensor of these embodiments can only report die position of one object on its sensor surface. If more dian one object is present, the position sensor of tiiis embodiment computes die centroid position of the combined set of objects. However, unlike prior art, because the entire pad is being profiled, enough information is available to discern simple multi-finger gestures to allow for a more powerful user interface.
- a variety of noise reductio techniques are integrated into the system.
- a capacitance measurement technique which is easier to calibrate and implement is employed.
- Figure 1 is an overall block diagram of the capacitive position sensing system o die present invention.
- Figure 2a is a top view of an object position sensor transducer according to a presendy preferred embodiment of the invention showing die object position sensor surface laye including a top conductive trace layer and conductive pads connected to a bottom trace layer.
- Figure 2b is a bottom view of the object position sensor transducer of FIG. 2a showing the bottom conductive trace layer.
- Figure 2c is a composite view of the object position sensor transducer of FIGS. 2a and 2b showing both the top and bottom conductive trace layers.
- Figure 2d is a cross-sectional view of the object position sensor transducer of FIGS. 2a-2c.
- Figure 3 is a block diagram of sensor decoding electronics which may be used witii the sensor transducer in accordance with a preferred embodiment of die present invention.
- Figure 4a is a simplified schematic diagram of a charge integrator circuit which may be used in the present invention.
- Figure 4b is an illustrative schematic diagram of die charge integrator circuit of FIG. 4a.
- Figure 5 is a timing diagram of die operation of charge integrator circuit of FIGS. 4a and 4b.
- Figure 6 is a schematic diagram of an illustrative filter and sample/hold circuit for use in die present invention.
- Figure 7 is a more detailed block diagram of a presendy preferred arrangement of A/D converters for use in die present invention.
- Figure 8 is a block diagram of an illustrative arithmetic unit which may be used in die present invention.
- Figure 9 is a block diagram of a calibration unit which may be used with die arithmetic unit of Figure 8.
- Figure 10 is a schematic diagram of a bias voltage generating circuit useful in die present invention.
- die following description of die present invention is illustrative only and not in any way limiting.
- Other embodiments of die invention will readily suggest tiiemselves to such skilled persons.
- the present invention brings together in combination a number of unique features which allow for new applications not before possible. Because the object position sensor of die present invention has very low power requirements, it is beneficial for use in battery operated or low power applications such as lap top or portable computers . It is also a very low cost solution, has no moving parts (and is therefore virtually maintenance free), and uses die existing printed circuit board traces for sensors.
- the sensing technology of the present invention can be integrated into a computer motiierboard to even further lower its cost in computer applications. Similarly, in otiier applications die sensor can be part of an already existent circuit board. Because of its small size and low profile, the sensor technology of die present invention is useful in lap top or portable applications where volume is an important consideration.
- the sensor technology of the present invention requires circuit board space for only a single sensor interface chip that can interface direcdy to a microprocessor, plus the area needed on die printed circuit board for sensing.
- Capacitive position sensing system 10 can accurately determine d e position of a finger 12 or other conductive object proximate to or touching a sensing plane 14.
- the capacitance of a plurality of conductive lines running in a first direction e.g., "X”
- X input processing circuitry 16 die capacitance of a plurality of conductive lines running in a second direction
- Y input processing circuitry 18 Y input processing circuitry 18.
- the sensed capacitance values are digitized in botii X input processing circuitry 16 and Y input processing circuitry 18.
- X input processing circuitry 16 and Y input processing circuitry 18 are presented to aritiimetic unit 20, which uses the digital information to derive digital information representing the position and pressure of d e finger 12 or otiier conductive object relative to die sensing plane 14.
- the sensor material can be anything that allows creation of a conductive X/Y matrix of pads. This includes not only standard PC boards, but also includes but is not limited to flexible PC boards, conductive elastomer materials, silk-screened conductive lines, and piezo- electric Kynar plastic materials. This renders it useful as well in any portable equipment application or in human interface where the sensor needs to be molded to fit within the hand.
- the sensor can be conformed to any diree dimensional surface. Copper can be plated in two layers on most any surface contour producing d e sensor. This will allow d e sensor to be adapted to d e best ergonomic form needed for any particular application. This coupled with the "light-touch" feature will make it effortless to use in many applications.
- the sensor can also be used in an indirect manner, i.e it can have an insulating foam material covered by a conductive layer over the touch sensing surface and be used to detect any object (not just conductive) tiiat presses against it's surface.
- the matrix area is scalable by either varying the matrix trace spacing or by varying the number of traces. Large sensor areas are practical where more information is needed.
- the sensor technology of d e present invention also provides finger pressure information. This additional dimension of information may be used by programs to control special features such as "brush-width" modes in Paint programs, special menu accesses, etc., allowing provision of a more natural sensory input to computers. It has also been found useful for implementing "mouse click and drag" modes and for simple input gestures.
- the user will not even have to touch the surface to generate die minimum reaction. This feature can gready minimize user strain and allow for more flexible use.
- the sense system of the present invention depends on a transducer device capable of providing position and pressure information regarding die object contacting the transducer.
- a transducer device capable of providing position and pressure information regarding die object contacting the transducer.
- FIGS. 2a-2d top, bottom, composite, and cross-sectional views, respectively, are shown of a presendy-preferred sensing plane 14 comprising a touch sensor array 22 for use in the present invention. Since capacitance is exploited by tiiis embodiment of die present invention, the surface of touch sensor array 22 is designed to maximize d e capacitive coupling to a finger or other conductive object
- a presendy preferred touch sensor array 22 comprises a substrate 24 including a set of first conductive traces 26 disposed on a top surface 28 thereof and run in a first direction to comprise row positions of the array.
- a second set of conductive traces 30 are disposed on a bottom surface 32 thereof and run in a second direction preferably orthogonal to d e first direction to form the column positions of die array.
- the top and bottom conductive traces 26 and 30 are alternately in contact with periodic sense pads 34 comprising enlarged areas, shown as diamonds in FIGS. 2a-2c. While sense pads 34 are shown as diamonds in FIGS. 2a-2c, any shape, such as circles, which allows diem to be closely packed is equivalent for purposes of this invention.
- first conductive traces 26 will be referred to as being oriented in die “X” or “row” direction and may be referred to herein sometimes as “X lines” and die second conductive traces 30 will be referred to as being oriented in the "Y” or “column” direction and may be referred to herein sometimes as "Y lines”.
- the number and spacing of these sense pads 34 depends upon die resolution desired. For example, in an actual embodiment constructed according to die principles of the present invention, a 0.10 inch center-to-center diamond-shaped pattern of conductive pads disposed along a matrix of 15 rows and 15 columns of conductors is employed. Every other sense pad 34 in each direction in the pad pattern is connected to conductive traces on die top and bottom surfaces 28 and 32, respectively of substrate 24.
- Substrate 24 may be a printed circuit board, a flexible circuit board or any of number of available circuit interconnect technology structures. Its thickness is unimportant as lon as contact may be made therethrough from die bottom conductive traces 30 to tiieir sense pads 3 on the top surface 28.
- the printed circuit board comprising substrate 24 can be constructed usin standard industry techniques. Board thickness is not important Connections from the conductiv pads 34 to die bottom traces 30 may be made employing standard plated-dirough hole technique well known in the printed circuit board art
- the substrate material 24 ma have a thickness on die order of 0.005 to 0.010 inches. Then the diamonds on die upper surfac 28 and d e plated through holes that connect to the lower surface traces 30, can be omitted, furthe reducing die cost of the system.
- Insulating layer 36 is disposed over die sense pads 34 on top surface 28 t insulate a human finger or other object therefrom.
- Insulating layer 36 is preferably a thin laye (i.e., approximately 5 mils) to keep capacitive coupling large and may comprise a material, such a mylar, chosen for its protective and ergonomic characteristics.
- the term "significant capacitiv coupling" as used herein shall mean capacitive coupling having a magnitude greater than about 0. pF.
- the first capacitive effect is trans-capacitance, or coupling between sens pads 34
- d e second capacitive effect is self-capacitance, or coupling to virtual ground
- Sensing circuitry is coupled to d e sensor array 22 of the present invention and responds t changes in either or both of these capacitances. This is important because d e relative sizes of the two capacitances change gready depending on the user environment.
- the ability of the presen invention to detect changes in both self capacitance and trans-capacitance results in a very versatile system having a wide range of applications.
- a position sensor system including touch sensor array 22 and associated position detection circuitry will detect a finger position on a matrix of printed circuit board traces via d e capacitive effect of finger proximity t die sensor array 22.
- the position sensor system will report the X, Y position of a finger placed near the sensor array 22 to much finer resolution than die spacing between die row and colum traces 26 and 30.
- the position sensor according to this embodiment of the invention will als report a Z value proportional to the oudine of that finger and hence indicative of die pressure widi which the finger contacts die surface of insulating layer 36 over the sensing array 22.
- a very sensitive, light-touch detector circuit may be provided using adaptive analog and digital VLSI techniques.
- the circuit of the present invention is very robust and calibrates out process and systematic errors.
- the detector circuit of the present invention will process the capacitive input information and provide digital information which may be presented direcdy to a microprocessor.
- sensing circuitry is contained on a single sensor processor integrated circuit chip.
- the sensor processor chip can have any number of X and Y "matrix" inputs. The number of X and Y inputs does not have to be equal.
- the Integrated circuit has a digital bus as output.
- the sensor array has 15 traces in both die X and Y directions.
- the sensor processor chip thus has 15 X inputs and 15 Y inputs.
- An actual embodiment constructed according to the principles of die present invention employed 18 traces in the X direction and 24 traces in die Y direction.
- d e size of d e sensing matrix which may be employed in the present invention is arbitrary and will be dictated largely by design choice.
- the X and Y matrix nodes are driven and sensed in parallel, witii die capacitive information from each line indicating how close a finger is to that node.
- the scanned information provides a profile of die finger proximity in each dimension.
- the profile centroid is derived in both die X and Y directions and is the position in tiiat dimension.
- the profile curve of proximity is also integrated to provide die Z information.
- a second drive/sense metiiod the voltages on all of die X lines of the sensor matrix are simultaneously moved in a positive direction, while die voltages of die Y lines are moved in a negative direction.
- the voltages on all of the X lines of the sensor matrix are simultaneously moved in a negative direction, while the voltages of die Y lines are moved in a positive direction.
- This second drive/sense method accentuates transcapacitance and de- emphasizes virtual ground capacitance. As with the first drive/sense method, those of ordinary skill in the art will recognize that order of these two steps is somewhat arbitrary and may be reversed.
- FIG. 3 a block diagram of the presently preferred sensin circuitry 40 for use according to die present invention is presented.
- This block diagram, and di accompanying disclosure relates to the sensing circuitry in one dimension (X) only, and include the X input processing circuitry 16 of FIG. 1.
- X the sensing circuitry
- Y the opposite
- tiiat the tw dimensions do not need to be orthogonal to one anotiier.
- tiiey can be radial or of an odier nature to match die contour of die touch sensor array and other needs of die system.
- Tho of ordinary skill in the art will recognize that the technology disclosed herein could be applied well to a one-dimensional case where only one set of conductive traces is used.
- the capacitance at each sensor matrix node is represented by equivalent capacitor 42-1 dirough 42-n.
- the capacitance of capacitors 42-1 dirough 42-n comprises the capacitance o the matrix conductors and has a characteristic background value when no object (e.g., a finger) i proximate to the sensing plane of die sensor matrix.
- no object e.g., a finger
- th capacitance of capacitors 42-1 through 42-n increases in proportion to the size and proximity of th object.
- die capacitance at each sensor matrix node measured simultaneously using charge integrator circuits 44-1 through 44-n.
- Charge-integrato circuits 44-1 through 44-n serve to inject charge into the capacitances 42-1 through 42- respectively, and to develop an output voltage proportional to die capacitance sensed on di corresponding X matrix line.
- charge-integrator circuits 44-1 through 44-n are shown a bidirectional amplifier symbols.
- Each charge-integrator circuit 44-1 through 44-n is supplied wi an operating bias voltage by bias-voltage generating circuit 46.
- the phrase "proportional to the capacitance" means that die voltag signal generated is a monotonic function of d e sensed capacitance.
- the voltage is direcdy and linearly proportional to die capacitance sensed.
- monotonic functions including but not limited t inverse proportionality, and non-linear proportionality such as logarithmic or exponenti functions, could be employed in die present invention widiout departing from die principle disclosed herein.
- current-sensing as well as voltage-sensing techniques could b employed.
- die capacitance measurements are performed simultaneously across all inputs in one dimension to overcome a problem which is inherent in all prior art approaches that scan individual inputs.
- the problem with d e prior-art approach is that it is sensitive to high frequency and large amplitude noise (large dv/dt noise) that is coupled to the circuit via the touching object Such noise may distort the finger profile because of noise appearing in a later scan cycle but not an earlier one, due to a change in die noise level.
- the present invention overcomes this problem by "taking a snapshot" of all inputs simultaneously in X and then Y directions (or visa versa). Because the injected noise is proportional to the finger signal strength across all inputs, it is therefore symmetric around die finger centroid. Because it is symmetric around die finger centroid it does not affect die finger position. Additionally, die charge amplifier performs a differential measuring function to further reject common-mode noise.
- filter circuits 48-1 dirough 48-n are implemented as sample and hold switched capacitor filters.
- die filter circuits 48-1 through 48-n The desired voltage is captured by die filter circuits 48-1 through 48-n. As controlled by control circuitry, 56, die filter circuits 48-1 through 48-n will filter out any high frequency noise from the sensed signal. This is accomplished by choosing the capacitor for the filter to be much larger than die output capacitiance of charge integrator circuits 44- 1 dirough 44-n. In addition, tiiose of ordinary skill in the art will recognize that die switched capacitor filter circuits 48-1 through 48-n will capture the desired voltages and store them.
- d e capacitance information obtained in voltage form from die capacitance measurements is digitized and processed in digital format Accordingly, the voltages stored by filter circuits 48-1 through 48-n are stored in sample/hold circuits 50-1 dirough 50-n so that die remainder of the circuitry processes input data taken at die same time.
- Sample/hold circuits 50-1 through 50-n may be configured as conventional sample/hold circuits as is well known in the art.
- A/D converters 52 resolve die input voltage to a 10-bit wide digital signal (a resolution of one part in
- A/D converters 52 may be conventional successive approximation type converters as is known in the art.
- die background level (no object present) of the charge integrator outputs will be about 1 volt.
- the ⁇ V resulting from die presence of a finger or other object will typically be about 0.4 volt.
- the voltage range of the A/D converters 52 should therefore be in the range of between about 1-2 volts.
- V min and V max voltage reference points for the A/D converters
- tiiat noise will cause position jitter if tiiese reference voltages are fixed points.
- a solution to tiiis problem which is employed in the present invention is to dynamically generate d e V- ⁇ - and V ma -. reference voltages from reference capacitances 42- Vmin and 42-Vmax, sensed by charge integrator circuits 44- Vmin and 44-Vmax and processed by filter circuits 48-Vmin and 48-Vmax and stored in sample/hold circuits 50- Vmin and 50-Vmax .
- any common mode noise present when die signals are sampled from the sensor array will also be present in the V. ⁇ -, and V max reference voltage values and will tend to cancel.
- reference capacitances 44- Vmin and 44-Vmax may eitiier be discrete capacitors or extra traces in die sensor array.
- the V ⁇ reference voltage is generated from a capacitor having a value equal to the lowest capacitance expected to be encountered in die sensor array with no object present (about 12pF assuming a 2 inch square sensor array).
- the V max reference voltage is generated from a capacitor having a value equal to die largest capacitance expected to be encountered in die sensor array with an object present (about 16pF assuming a 2 inch square sensor array).
- arithmetic unit 20 The outputs of A/D converters 52 provide inputs to arithmetic unit 20.
- the function of arithmetic unit 20 is to compute the weighted average of the signals on the individual sense lines in both die X and Y directions in the touch sensor array 22.
- aritiimetic unit 20 is shared by die X input processing circuitry 16 and die Y input processing circuitry 18 as shown in FIG. 1.
- Control circuitry 56 of FIG. 3 orchestrates the operation of die remainder of die circuitry. Because the system is discretely sampled and pipelined in its operation, control circuitry
- control circuitry 56 is present to manage the signal flow.
- the functions performed by control circuitry 56 may be conventionally developed via what is commonly known in the art as a state machine or microcontroller.
- the structure and operation of the individual blocks of FIG. 3 will now be disclosed. Referring now to FIGS. 4a, 4b, and 5, a typical charge integrator circuit will be described.
- Charge integrator circuit 44 is shown as a simplified schematic diagram in FIG. 4a and as an illustrative schematic diagram in FIG. 4b.
- the timing of the operation of charge integrator circuit 44 is shown in FIG. 5. These timing signals are provided by die controller block 56.
- Charge integrator circuit 44 is based on die fundamental physical phenomena of using a current to charge a capacitor. If the capacitor is charged for a constant time by a constant current, then a voltage will be produced on die capacitor which is inversely proportional to the capacitance.
- the capacitance to be charged is the sensor matrix line capacitance 42 in parallel with an internal capacitor. This internal capacitor will contain the voltage of interest.
- a charge integrator circuit input node 60 is connected to one of the X (or Y) lines of the sensor matrix.
- a first shorting switch 62 is connected between die charge integrator circuit input node 60 and V DD , die positive supply rail.
- a second shorting switch 64 is connected between the charge integrator circuit input node 60 and ground, die negative supply rail.
- a positive constant current source 66 is connected to V D D, the positive supply rail and to the charge integrator circuit input node 60 and dirough a first current source switch 68.
- a negative constant current source 70 is connected to ground and to the charge integrator circuit input node 60 and dirough a second current source switch 72. It is obvious that other high and low voltage rails could be used in place of V DD and ground.
- a first internal capacitor 74 is connected between V DD and output node 76 of charge integrator circuit 44.
- a positive voltage storage switch 78 is connected between output node 76 and input node 60.
- a second internal capacitor 80 has one of its plates connected to ground dirough a switch 82 and to output node 76 of charge integrator circuit 44 through a switch 84, and die other one of its plates connected to input node 60 dirough a negative voltage storage switch 86 and to V DD through a switch 88.
- the capacitance of first and second internal capacitances 74 and 80 should be a small fraction (i.e., about 10%) of d e capacitance of the individual sensor matrix lines. In a typical embodiment die sensor matrix line capacitance will be about lOpF and die capacitance of capacitors 74 and 80 should be about lpF.
- the approach used is a differential measurement for added noise immunity, die benefit of which is tiiat any low frequency common mode noise gets subtracted out.
- all switches are open unless they are noted as closed.
- First die sensor matrix line is momentarily shorted to V DD through switch 62, switch 78 is closed connecting capacitor 74 in parallel with the capacitance of the sensor line. Then the parallel capacitor combination is discharged witii a constant current from current source 70 through switch 72 for a fixed time period. At d e end of the fixed time period, switch 78 is opened, tiius storing the voltage on die sensor matrix line on capacitor 74.
- the sensor line is then momentarily shorted to ground through switch 64, and switches 82 and 86 are closed to place capacitor 80 in parallel with the capacitance of die sensor line.
- Switch 68 is closed and the parallel capacitor combination is charged with a constant current from current source 66 for a fixed time period equal to the fixed time period of die first cycle.
- switch 86 is opened, tiius storing die voltage on die sensor matrix line on capacitor 80.
- the first and second measured voltages are then averaged. This is accomplished by opening switch 82 and closing switches 88 and 84, which places capacitor 80 in parallel with capacitor 74. Because capacitors 74 and 80 have die same capacitance, die resulting voltage across diem is equal to the average of the voltages across each individually. This final result is the value that is then passed on to die appropriate one of filter circuits 48-1 through 48-n.
- the low frequency noise notably 50/60 Hz and their harmonics, behaves as a DC current component tiiat adds in one measurement and subtracts in die other. When the two results are added together that noise component averages to zero.
- the amount of noise rejection is a function of how quickly in succession the two opposing charge-up and charge-down cycles are performed as will be disclosed herein.
- One of the reasons for die choice of tiiis charge integrator circuit is that it allows measurements to be taken quickly.
- FIG. 4b a more complete schematic diagram of an illustrative embodiment of charge integrator circuit 44 of the simplified diagram of FIG. 4a is shown.
- Input node 60 is shown connected to V D D and ground through pass gates 90 and 92, which replace switches 62 and 64 of FIG. 4a.
- Pass gate 90 is controlled by a signal ResetUp presented to its control input and pass gate 92 is controlled by a signal ResetDn presented to its control input
- pass gates 90 and 92, as well as all of die otiier pass gates which are represented by die same symbol in FIG. 4b may be conventional CMOS pass gates as are known in the art.
- die pass gate will be off when its control input is held low and will be on and present a low impedance connection when its control input is held high.
- P-Channel MOS transistors 94 and 96 are configured as a current mirror.
- P- Channel MOS transistor 94 serves as the current source 66 and pass gate 98 serves as switch 68 of FIG. 4a.
- the control input of pass gate 98 is controlled by a signal StepUp.
- N-Channel MOS transistors 100 and 102 are also configured as a current mirror.
- N-Channel MOS transistor 100 serves as the current source 70 and pass gate 104 serves as switch 72 of FIG. 4a.
- the control input of pass gate 104 is controlled by a signal StepDn.
- P-Channel MOS transistor 106 and N-Channel MOS transistor 108 are placed in series witii P-Channel MOS current mirror transistor 96 and N-Channel MOS current mirror transistor 102.
- the control gate of P-Channel MOS transistor 106 is driven by an enable signal EN, which turns on P-Channel MOS transistor 106 to energize die current mirrors.
- This device is used as a power conservation device so diat the charge integrator circuit 44 may be turned off to conserve power when it is not in use.
- N-Channel MOS transistor 108 has its gate driven by a reference voltage Vbias, which sets the current through current mirror transistors 96 and 108.
- Vbias is set by a servo feedback circuit as will be disclosed in more detail witii reference to FIG. 10. Those of ordinary skill in the art will appreciate that this embodiment allows calibration to occur in real time (via long time constant feedback) thereby zeroing out any long term effects due to sensor environmental changes.
- Vbias is common for all charge integrator circuits 44-1 through 44-n and 44-Vmax and 44- Vmin.
- proper sizing of MOS transistors 102 and 108 may provide temperature compensation. This is accomplished by taking advantage of die fact tiiat d e threshold of N- Channel MOS transistor 108 reduces witii temperature while the mobility of both N-Channel MOS transistors 102 and 108 reduce with temperature.
- the threshold reduction has die effect of increasing die current while die mobility reduction has die effect of decreasing die current
- Capacitor 74 has one plate connected to V DD and die otiier plate connected to die output node 76 and to die input node 60 dirough pass gate 110, shown as switch 78 in FIG. 4a.
- the control input of pass gate 110 is driven by the control signal SUp.
- One plate of capacitor 80 is connected to input node 60 dirough pass gate 112 (switch 86 in FIG. 4a) and to VDD dirough pass gate 114 (switch 82 in FIG.4a).
- the control input of pass gate 112 is driven by die control signal SDn and die control input of pass gate 114 is driven by die control signal ChUp.
- the other plate of capacitor 80 is connected to ground through N-Channel MOS transistor 116 (switch 82 in FIG. 4a) and to output node 76 through pass gate 118 (switch 84 in FIG. 4a).
- the control input of pass gate 118 is driven by control signal Share.
- the EN (enable) control signal goes active by going to Ov. This turns on die current mirrors and energizes the charge and discharge current sources, MOS transistors 94 and 100.
- the ResetUp control signal is active high at this time, which shorts the input node 60 (and die sensor line to which it is connected) to V DD .
- the SUp control signal is also active high at tiiis time which connects capacitor 74 and die output node 76 to input node 60. This arrangement guarantees that the following discharge portion of the operating cycle always starts from a known equilibrium state.
- StepDn control signal goes active, connecting MOS transistor 100, the discharge current source, to the input node 60 and its associated sensor line.
- StepDn is active for a set amount of time, and die negative constant current source discharges die combined capacitance of the sensor line and capacitor 74tivus lowering its voltage during tiiat time.
- StepDn is tiien turned off.
- a short time later d e SUp control signal goes inactive, storing the measured voltage on capacitor 74. That ends die discharge cycle.
- die ResetDn control signal becomes active and shorts the sensor line to ground.
- die SDn and ChDn control signals become active and connect capacitor 80 between ground and the sensor line. Capacitor 80 is discharged to ground, guaranteeing that the following charge up cycle always starts from a known state.
- the charge up cycle starts after ResetDn control signal becomes inactive and die StepUp control signal becomes active.
- the current charging source MOS transistor 94
- MOS transistor 94 is connected to the sensor line and supplies a constant surrent to charge the sensor line by increasing die voltage tiiereon.
- the StepUp control signal is active for a set amount of time (preferably equal to the time for the previously mentioned cycle) allowing the capacitance to charge, and dien it is turned off.
- the SDn control signal then goes inactive, leaving die measured voltage across capacitor 80.
- die Share control signal becomes active which connects the first plate of capacitor 80 to output node 76, thus placing capacitors 74 and 80 in parallel.
- This has die effect of averaging die voltages across die two capacitors, tiius subtracting out common-mode noise as previously described. This average voltage is also then available on output node 76.
- the ChDn and ChUp signals should be asserted witii respect to each other within a time period much less than a quarter of the period of the noise to be cancelled in order to take advantage of tiiis feature of the present invention.
- FIG. 6 a schematic diagram of an illustrative switched capacitor filter circuit 48 which may be used in die present invention is shown.
- this switched capacitor filter circuit which comprises an input node 120, a pass gate 122 having a control input driven by a Sample control signal, a capacitor 124 connected between d e output of die pass gate 126 and a fixed voltage such as ground, and an output node comprising d e common connection between the capacitor 124 and d e output of die pass gate 126.
- capacitor 116 will have a capacitance of about 10 pF.
- the switched capacitor filter 48 is in part a sample/hold circuit and has a filter time constant which is K times d e period of sample, where K is die ratio of capacitor 124 to die sum of capacitors 74 and 80 of d e charge integrator circuit 44 of FIGS. 4a and 4b to which it is connected.
- FIG. 7 a more detailed block diagram of a presendy preferred arrangement of A/D converters 52 of FIG. 3 is presented.
- A/D converters 52 of FIG. 3 There are fewer A/D converters than there are lines in die touch sensor array, and die inputs to d e A/D converters are multiplexed to share each of the individual A D converters among several lines in the touch sensor array.
- the arrangement in FIG. 7 is more efficient in d e use of integrated circuit layout area than providing individual A/D converters for each input line.
- Analog multiplexer 130 has six outputs, each of which drives the input of an individual A/D converter 52- 1 dirough 52-6.
- the internal arrangement of analog multiplexer 130 is such tiiat four different ones of die inputs are multiplexed to each of die outputs.
- Analog multiplexer 130 has been conceptually drawn as six internal multiplexer blocks 132-1 through 132-6.
- inputs taken from sample/hold circuits 50-1 dirough 50-4 are multiplexed to the output of internal multiplexer block 132-1 which drives A/D converter 52-1.
- inputs taken from sample/hold circuits 50-5 through 50-8 are multiplexed to the output of internal multiplexer block 132-2 which drives A/D converter 52-2;
- inputs taken from sample/hold circuits 50-9 through 50-12 are multiplexed to the output of internal multiplexer block 132-3 which drives A/D converter 52-3;
- inputs taken from sample/hold circuits 50-13 through 50-16 are multiplexed to the output of internal multiplexer block 132-4 which drives A/D converter 52-4;
- inputs taken from sample/hold circuits 50-17 through 50-20 are multiplexed to the output of internal multiplexer block 132-51 which drives A/D converter 52-5;
- inputs taken from sample/hold circuits 50-21 dirough 50-24 are multiplexed to die output of internal multiplexer block 132-6 which drives A/D converter 52-6.
- Analog multiplexer 130 has a set of control inputs schematically represented by bus 134.
- bus 134 each of internal multiplexers 132-1 dirough 132-6 are four-input multiplexers and tiius control bus 134 may comprise a two-bit bus for a one- of-four selection.
- tiiat die arrangement of FIG. 7 is merely one of a number of specific solutions to the task of A/D conversion from twenty-four channels, and that other satisfactory equivalent arrangements are possible.
- multiplexers 132-1 through 132-6 will pass, in sequence, the analog voltages present on their first through fourth inputs on to die inputs of A/D converters 52-1 through 52-6 respectively. After the analog values have settled in die inputs of A/D converters 52-1 through 52-6, a CONVERT command is asserted on common A/D control line 136 to begin the A/D conversion process.
- registers 138-1 through 138-6 may each comprise a two- word register, so tiiat one word may be read out of die registers to arithmetic unit 54 while a second word is being written into the registers in order to maximize die speed of die system.
- the design of such registers is conventional in the art
- tiiat aritiimetic unit 20 processes information from both the X and Y dimensions, i.e., from X input processing circuit 16 and Y input processing circuit 18 of FIG. 1.
- the object position in either direction may be determined by evaluating the weighted average of die capacitances measured on the individual sense line of die sensor array 10.
- die X direction is used, but those of ordinary skill in the art will recognize that the discussion applies to die determination of the weighted average in the Y direction as well.
- die weighted average may be determined as follows:
- die position can be expressed as:
- tiiis expression is seen to be equivalent to: n n
- tiiat aritiimetic unit 20 includes numerator and denominator accumulators 150 and 152 and Y numerator and denominato accumulators 154 and 156.
- the source of operand data for X numerator and denominato accumulators 150 and 152 and Y numerator and denominator accumulators 154 and 156 are th registers 138-1 through 138-6 in each (X and Y) direction of the sensor array 22 of FIG. 1.
- Th X and Y denominator accumulators 152 and 156 sum up the digital results from die A/ conversions.
- the X and Y numerator accumulators 150 and 154 compute die weighted sum of di input data rather tiian the straight sum.
- Accumulators 150, 152, 154, and 156 may be configure as hardware elements or as software running on a microprocessor as will be readily understood b those of ordinary skill in the art.
- numerator accumulators 150 an 154 compute the expression of Eq. 4: n
- ⁇ ⁇ ⁇ Q i-0 and denominator accumulators 152 and 156 compute die expression of Eq.4: n
- X and Y numerator and denominator offset registers 158, 160, 162, and 164 are subtracted from die results stored in the accumulators 150, 152, 154, and 156 in adders 166, 168, 170, and 172.
- Adder 166 subtracts the offset O NX stored in X numerator offset register 158.
- Adder 168 subtracts the offset O DX stored in X denominator offset register 160.
- Adder 170 subtracts the offset Owy stored in X numerator offset register 162.
- Adder 172 subtracts the offset
- Orj ⁇ stored in Y denominator offset register 164 is divided by division blocks 174 and 176 to produce the X and Y position data, and die X and Y denominator pair is used by block 178 to produce Z axis (pressure) data.
- the function performed by block 178 will be disclosed later herein.
- the offsets O D ⁇ , O NX , O D ⁇ , and O NY are sampled from the accumulator contents when directed by calibration unit 180.
- the numerator and denominator accumulators 150, 152, 154, and 156 are set to zero during system startup. If the multiplexed A D converters as shown in FIG. 7 are employed, die digitized voltage data in die first word of register 138-1 (representing die voltage at die output of sample/hold circuit 50-1) is added to d e sum in die accumulator and d e result stored in d e accumulator. In succession, the digitized voltage values stored in the first word of registers 138-2 through 138-6 (representing the voltage at the outputs of sample/hold circuits 50-5, 50-9, 50-17, and 50-21, respectively) are added to the sums in the accumulators and die results stored in the accumulators.
- A/D converters 52-1 dirough 52-6 may at this time be converting the voltages present at the outputs of sample/hold circuits 50-2, 50-6, 50-10, 50-14, 50-18, and 50-22 and storing the digitized values in the second words of registers 138-1 through 138-6 respectively.
- the digitized voltage values stored in die second words of registers 138-1 through 138-6 (representing the voltage at the outputs of-sample hold circuits 50- 2, 50-6, 50-10, 50-14, 50-18, and 50-22, respectively) are added to the sum in the accumulator and die result stored in the accumulator.
- the digitized voltage values stored in the first words o registers 138-1 through 138-6 (representing die voltage at the outputs of sample/hold circuits 50- 50-7, 50-11, 50-15, 50-19, and 50-23, respectively) are added to die sum in die accumulator an die result stored in d e accumulator, followed by digitized voltage values stored in die secon words of registers 138-1 through 138-6 (representing the voltage at die outputs of sample/hol circuits 50-4, 50-8, 50-12, 50-16, 50-20, and 50-24, respectively).
- the accumulators hold the sums of all of die individua digitized voltage values.
- the digital values stored in die O N and O D offset registers 158 and 16 are now respectively subtracted from the values stored in the numerator and denominato accumulators.
- the division operation in dividers 174 and 176 tiien completes the weighte average computation.
- the division operation may also be performed by an external microprocesso which can fetch the values stored in the accumulators or perform die accumulations itself.
- an external microprocesso which can fetch the values stored in the accumulators or perform die accumulations itself.
- die additiona processing overhead presented to such external microprocessor by this division operation i minimal.
- a dedicated microprocessor may be included on chip to handle thes processing tasks without departing from die invention disclosed herein.
- the above disclosed processing takes place within about 1 millisecond and may b repeatedly performed.
- Current mouse standards update position information 40 times per second and thus the apparatus of the present invention may easily be operated at tiiis repetition rate.
- die accumulators may be cleared and die process repeated, die values ma also be allowed to remain in the accumulators. If this is done, an averaging function may b implemented to further filter out noise.
- a number o samples are taken and run through the accumulators widiout clearing them at die end of di processing sequence. As presently preferred, twenty-five samples are processed before a singl division result is taken for use by die system, tiius gready reducing the effects of transient syste noise spikes.
- the system of the present invention is adaptable to changing conditions, such as component aging, changing capacitance due to humidity, and contamination of the touch surface, etc.
- die present invention effectively minimizes ambient noise.
- tiiese effects are taken into consideration in three ways. First the offset values O N and O D are dynamically updated to accommodate changing conditions. Second, a servo- feedback circuit is provided to determine the bias voltage used to set the bias of the charge- integrator circuits 44-1 through 44-n. Third, as previously disclosed herein, the reference voltage points for V max and V-. ⁇ of die A D converters are also dynamically altered to increase the signal to noise margin.
- the calibration unit 150 executes an algoridim to establish the numerator and denominator offset values by attempting to determine when no finger or other conductive object is proximate to the touch sensor array 22.
- the O N and Op offset values represent the baseline values of the array capacitances with no object present These values are also updated according to the present invention since baseline levels which are too low or too high have the effect of shifting the apparent position of the object depending on die sign of die error. These values are established by selection of the values read when no object is present at die sensor array 22. Since tiiere is no external way to "know" when no object is present at sensor array 22, an algorithm according to anodier aspect of die present invention is used to establish and dynamically update tiiese offset values. When the calibration unit sees a Z value which appears typical of the Z values when no finger is present, it instructs d e offset registers (158, 160, 162, and 164 of FIG.
- the decision to update die offset values is based on die behavior of die sensor array 22 in only one of die X or Y directions, but when die decision is made all four offsets (Ow, ⁇ , Opx,
- ONY, and O DY are updated.
- the decision to update may be individually made for each direction according to die criteria set forth herein.
- the calibration algoridim works by monitoring changes in a selected one of die denominator accumulator values.
- die sensitivity to changes in capacitance of one of the sets of conductive lines in die touch sensor array 22 is greater than the sensitivity to changes in capacitance of the other one of the sets of conductive lines in die touch sensor array 22.
- the set of conductive lines having the greater sensitivity to capacitance changes is die one which is physically located above the conductive lines in the otiier direction and therefore closest to the touch surface of the sensor array 22.
- the upper set of conductive lines tends to partially shield die lower set of conductive lines from capacitive changes occurring above the surface of the sensor array 22.
- the finger pressure is obtained by summing the capacitances measured on die sense lines. This value is already present in die denominator accumulator after subtracting the offset O D . A finger is present if the pressure exceeds a suitable tiireshold value. This threshold may be chosen experimentally and is a function of surface material and circuit timing. The tiireshold may be adjusted to suit the tastes of die individual user.
- the pressure reported by the device is a simple function f(Xn YD) °f me denominators for die X and Y directions as implemented in block 178 of FIG. 8. Possible functions include choosing one preferred denominator value, or summing the denominators. In a presently preferred embodiment, die smaller of the two denominators is chosen. This choice has the desirable effect of causing the pressure to go below the threshold if the finger moves slightiy off the edge of die pad, where die X sensors are producing valid data, but the Y sensors are not, or vise versa. This acts as an electronic bezel which can take the place of a mechanical bezel at the periphery of the sensor area.
- the Y denominator is chosen for monitoring because it is the most sensitive.
- the chosen denominator is referred to as Z for die purposes of the calibration algorithm.
- the current saved offset value for this denominator is referred to as O ⁇
- the goal of the calibration algorithm is to track gradual variations in the resting Z level while making sure not to calibrate to the finger, nor to calibrate to instantaneous spikes arising from noise.
- die calibration algorithm could be implemented in digital or analog hardware, or in software. In a current embodiment actually tested by die inventors, it is implemented in software.
- History buffer 184 which operates in conjunction with filter 182, keeps a "running average” of recent Z values.
- the current running average F z is updated according to the formula:
- ⁇ is a constant factor between 0 and 1 and typically close to 1 and Z is the current Z value.
- alpha is approximately 0.95. The intention is for FZ to change slowly enough to follow gradual variations, without being greatly affected by short perturbations in Z.
- the filter 182 receives a signal ENABLE from control unit 186.
- the running average F z is updated based on new Z values only when ENABLE is asserted. If ENABLE is deasserted, F z remains constant and is unaffected by current Z.
- the history buffer 184 records die several most recent values of FZ. In the present embodiment, die history buffer records the two previous FZ values.
- the history buffer might be implemented as a shift register, circular queue, or analog delay line.
- the history buffer receives a REWIND signal from control unit 186, it restores the current running average F z to the oldest saved value. It is as if die filter 182 were "retroactively" disabled for an amount of time corresponding to die deptii of die history buffer.
- the purpose of the history buffer is to permit such retroactive disabling.
- the current running average F z is compared against the current Z value and d e current offset O- ⁇ by absolute difference units 188 and 190, and comparator 192.
- Absolute difference unit 188 subtracts the values Z and F z and outputs the absolute value of their difference.
- Absolute difference unit 1 0 subtracts the values O z and F z and outputs die absolute value of tiieir difference.
- Comparator 192 asserts the UPDATE signal if the output of absolute difference unit 188 is less than the output of absolute difference unit 190, i.e., if F z is closer to Z than it is to C ⁇ .
- the UPDATE signal will tend to be asserted when die mean value of Z shifts to a new resting level. It will tend not to be asserted when Z makes a brief excursion away from its normal resting level.
- the filter constant a determines die lengtii of an excursion which will be considered "brief for tiiis purpose.
- Subtractor unit 194 is a simple sub tractor that computes the signed difference between Z and O z .
- This subtractor is actually redundant with subtractor 172 in figure 8, and so may be merged with it in the actual implementation.
- the output C z of this subtractor is the calibrated Z value, an estimate of the finger pressure.
- This pressure value is compared against a positive and negative Z threshold by comparators 196 and 198. These thresholds are shown as ZJJJ and -Z jj , although they are not actually required to be equal in magnitude.
- the signal FINGER is asserted indicating the possible presence of a finger.
- the ZJ ⁇ tiireshold used by the calibration unit is similar to tiiat used by the rest of the system to detect the presence of die finger, or it may have different value.
- the calibration Z ⁇ is set somewhat lower than th main Z T H to ensure that die calibration unit makes a conservative choice about die presence of finger.
- Control logic 186 is responsible for preventing running average F z from bein influenced by Z values tiiat occur when a finger is present
- Output ENABLE is generally of when the FINGER signal is true, and on when the FINGER signal is false. However, when FINGER transitions from false to true, the control logic also pulses the REWIND signal. When FINGER transitions from true to false, the control logic waits a short amount of time (comparable to the deptii of the history buffer) before asserting ENABLE. Thus, the runnin average is prevented from following Z whenever a finger is present, as well as for a short time before and after die finger is present
- Calibration logic 200 produces signal RECAL from the outputs of the three comparators 192, 196, and 198.
- RECAL is asserted, die offset registers O N and On will b reloaded from die current accumulator values.
- RECAL is produced from die following logic equation:
- RECAL FORCE or (UPDATE and not FINGER).
- calibration logic 200 arranges to assert RECAL once when the system is firs initialized, possibly after a brief period to wait for the charge integrators and otiier circuits to stabilize.
- control logic 186 and calibration logic 200 From the descriptions of control logic 186 and calibration logic 200, it will be apparent to those of ordinary skill in the art that these blocks can be readily configured usin conventional logic as a matter of simple and routine logic design.
- the calibration algoridim described is not specific to the particular system of charge integrators and accumulators of the current invention. Rather, it could be employed in any touch sensor which produces proximity or pressure data in which it is desired to maintain a calibration point reflecting the state of the sensor when no finger or spurious noise is present.
- bias voltage generating circuit 46 useful in the present invention is shown in schematic diagram form.
- all of the bias transistors 108 (FIG. 4b) of charge integrator circuits 44-1 through 44-n have tiieir gates connected to a single source of bias voltage, altiiough persons of ordinary skill in die art recognize that other arrangements are possible.
- the bias voltage generating circuit As may be seen from an examination of FIG. 10, the bias voltage generating circuit
- a reference source which approximates die current source function of a typical one of the charge integrator circuits 44-1 through 44-n includes a capacitor 204 having one of its plates grounded. The other one of its plates is connected to die V D D power supply through a first pass gate 206 and to a current source transistor 208 through a second passgate 210.
- a filter circuit 212, identical to the filter circuits 48-1 through 48-n and controlled by the same signal as filter circuits 48-1 through 48-n is connected to sample the voltage on capacitor 204 in die same manner that the filter-and-sample/hold circuits 48-1 through 48-n sample the voltages on the sensor conductor capacitances in the sensor array 22.
- the output of filter circuit 212 is fed to die non-inverting input of a weak transconductance amplifier 214, having a bias current in the range of from about 0.1-0.2 ⁇ A.
- the inverting input of the transconductance amplifier 214 is connected to a fixed voltage of about 1 volt generated, for example, by diode 216 and resistor 218.
- the output of transconductance amplifier 214 is shunted by capacitor 220 and also by capacitor 222 dirough passgate 224.
- Capacitor 222 is chosen to be much larger than capacitor 220. In a typical embodiment of the present invention, capacitor 220 may be about 0.2pF and capacitor 222 may be about lOpF.
- Capacitor 222 is connected to d e gate of N-Channel MOS transistor 226, which has its drain connected to the drain and gate of P-Channel MOS transistor 228 and its source connected to die drain and gate of N-Channel MOS transistor 230.
- the source of P-Channel MOS transistor 228 is connected to V D D and die source of N-Channel MOS transistor 230 is connected to ground.
- the common drain connection of transistors 226 and 230 is die bias voltage output node.
- An optional passgate 232 may be connected between a fixed voltage source (e.g., about 2 volts) and capacitor 222 dirough a passgate 234. Passgate 234 may be used to initializ the bias generating circuit 200 on startup by charging capacitor 222 to the fixed voltage.
- a fixed voltage source e.g., about 2 volts
- the filter circuit 210 takes a new sample. If the ne sample differs from the previous sample, the output voltage of transconductance amplifier 211 wil change and start to charge or discharge capacitor 218 to a new voltage.
- Passgate 222 is switche on for a short time (i.e., about l ⁇ sec) and die voltages on capacitors 218 and 220 try to averag tiiemselves. Due to the large size difference between capacitors 218 and 220, capacitor 218 canno supply enough charge to equalize the voltage during the period when passgate 222 is open. Thi arrangement prevents large changes in bias voltage from cycle to cycle.
- Capacitor 202 should look as much as possible like one of the sensor arra channels and has a value equal to the background capacitance of a typical sensor line, (i.e., wit no object proximate or present capacitance component).
- Capacitor 202 may be formed in severa ways.
- Capacitor 202 may comprise an extra sensor line in a part of the sensor array, configured t approximate one of the active sensor lines but shielded from finger capacitance by a ground plane, etc.
- capacitor 202 may be a capacitor formed in d e integrated circuit or connecte thereto and having a value selected to match that of a typical sensor line.
- the signal source comprising capacitor 202 and filter circuit 210 is somewhat like the circuitry for generating e max and v.,, ! ,, reference voltages, in that it mimics a typical sensor line.
- one of the actual sensor lines may be employed to set d e bias voltage.
- the measured voltage on die two end-point sensor lines may be compared and di one having die lowest value may be selected on the theory that, if a finger or other object is proximate to the sensor array, it will not be present at sensor lines located at the opposite edges o die array.
- the increased sensitivity of the touch sensor system of the present invention allow for a lighter input finger touch which makes it easy for human use. Increased sensitivity als makes it easier to use other input objects, like pen styli, etc. Additionally tiiis sensitivity allow for a trade-off against a thicker protective layer, or different materials, which both allow for lower manufacturing costs.
- the data acquisition rate has been increased by about a factor of 30 over die prior art. This offers several obvious side effects. First, for die same level of signal processing, the circuitry can be turned off most of die time and reduce power consumption by roughly a factor of 30 in the analog section of the design. Second, since more data is available, more signal processing, such as filtering, and gesture recognition, can be performed.
- the sensor electronic circuit employed in die present invention is very robust and calibrates out process and systematic errors. It will process the capacitive information from die sensor and provide digital information to an external device, for example, a microprocessor.
- the senor of the present invention may be placed in a convenient location, e.g., below the "space bar" key in a portable computer.
- a convenient location e.g., below the "space bar” key in a portable computer.
- the thumb of the user may be used as die position pointer on the sensor to control the cursor position on the computer screen.
- the cursor may then be moved without die need for die user's fingers to leave the keyboard.
- tiiis is similar to the concept of the Macintosh Power Book with it's trackball, however the present invention provides a significant advantage in size over the track ball. Extensions of this basic idea are possible in that two sensors could be placed below the "space bar” key for even more feature control.
- the computer display with it's cursor feedback is one small example of a very general area of application where a display could be a field of lights or LED's, an LCD display, or a CRT. Examples include touch controls on laboratory equipment where present equipment uses a knob/button/touch screen combination. Because of the articulating ability of this interface, one or more of those inputs could be combined into one of d e inputs described widi respect to the present invention.
- Consumer Electronic Equipment (stereos, graphic equalizers, mixers) applications often utilize significant front panel surface area for slide potentiometers because variable control is needed.
- the present invention can provide such control in one small touch pad location. As Electronic Home Systems become more common, denser and more powerful human interface is needed.
- the sensor technology of the present invention permits a very dense control panel. Hand Held TV/VCR/Stereo controls could be ergonomically formed and allow for more powerful features if this sensor technology is used.
- the sensor of the present invention can be conformed to any surface and can b made to detect multiple touching points, making possible a more powerful joystick.
- the uniqu pressure detection ability of the sensor technology of the present invention is also key to thi application. Computer games, "remote" controls (hobby electronics, planes) , and machine too controls are a few examples of applications which would benefit from the sensor technology of th present invention.
- the sensor technology of the present invention can best detect any conductin material pressing against it.
- the sensor of the present invention may also indirectl detect pressure from any object being handled, regardless of its electrical conductivity.
Abstract
Description
Claims
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1019970701215A KR100274772B1 (en) | 1994-09-02 | 1995-09-01 | Object position detector |
DE69527295T DE69527295T2 (en) | 1994-09-02 | 1995-09-01 | POSITION DETECTOR OF AN OBJECT |
JP50961496A JP3526577B2 (en) | 1994-09-02 | 1995-09-01 | Object position detector |
AU35444/95A AU3544495A (en) | 1994-09-02 | 1995-09-01 | Object position detector |
EP95932385A EP0777888B1 (en) | 1994-09-02 | 1995-09-01 | Object position detector |
HK98101835A HK1002568A1 (en) | 1994-09-02 | 1998-03-05 | Object position detector. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/300,387 US5914465A (en) | 1992-06-08 | 1994-09-02 | Object position detector |
US08/300,387 | 1994-09-02 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1996007981A1 true WO1996007981A1 (en) | 1996-03-14 |
Family
ID=23158895
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1995/011180 WO1996007981A1 (en) | 1994-09-02 | 1995-09-01 | Object position detector |
Country Status (9)
Country | Link |
---|---|
US (1) | US5914465A (en) |
EP (1) | EP0777888B1 (en) |
JP (1) | JP3526577B2 (en) |
KR (1) | KR100274772B1 (en) |
CN (1) | CN1153173C (en) |
AU (1) | AU3544495A (en) |
DE (1) | DE69527295T2 (en) |
HK (1) | HK1002568A1 (en) |
WO (1) | WO1996007981A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007242035A (en) * | 1998-01-26 | 2007-09-20 | Wayne Westerman | Multi-touch surface device |
EP2506130A1 (en) * | 2009-10-09 | 2012-10-03 | Egalax_Empia Technology Inc. | Method and device for capacitive detecting position |
US9081426B2 (en) | 1992-03-05 | 2015-07-14 | Anascape, Ltd. | Image controller |
Families Citing this family (240)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6239389B1 (en) | 1992-06-08 | 2001-05-29 | Synaptics, Inc. | Object position detection system and method |
US5880411A (en) | 1992-06-08 | 1999-03-09 | Synaptics, Incorporated | Object position detector with edge motion feature and gesture recognition |
GB9422911D0 (en) * | 1994-11-14 | 1995-01-04 | Moonstone Technology Ltd | Capacitive touch detectors |
US7167748B2 (en) | 1996-01-08 | 2007-01-23 | Impulse Dynamics Nv | Electrical muscle controller |
US8321013B2 (en) | 1996-01-08 | 2012-11-27 | Impulse Dynamics, N.V. | Electrical muscle controller and pacing with hemodynamic enhancement |
JP4175662B2 (en) | 1996-01-08 | 2008-11-05 | インパルス ダイナミクス エヌ.ヴイ. | Electric muscle control device |
US8825152B2 (en) | 1996-01-08 | 2014-09-02 | Impulse Dynamics, N.V. | Modulation of intracellular calcium concentration using non-excitatory electrical signals applied to the tissue |
US9289618B1 (en) | 1996-01-08 | 2016-03-22 | Impulse Dynamics Nv | Electrical muscle controller |
US9713723B2 (en) | 1996-01-11 | 2017-07-25 | Impulse Dynamics Nv | Signal delivery through the right ventricular septum |
US8674932B2 (en) | 1996-07-05 | 2014-03-18 | Anascape, Ltd. | Image controller |
US6288707B1 (en) * | 1996-07-29 | 2001-09-11 | Harald Philipp | Capacitive position sensor |
US6380929B1 (en) | 1996-09-20 | 2002-04-30 | Synaptics, Incorporated | Pen drawing computer input device |
US7663607B2 (en) | 2004-05-06 | 2010-02-16 | Apple Inc. | Multipoint touchscreen |
US7265494B2 (en) | 1998-10-09 | 2007-09-04 | Azoteq Pty Ltd. | Intelligent user interface with touch sensor technology |
US7528508B2 (en) | 1998-10-09 | 2009-05-05 | Azoteq Pty Ltd. | Touch sensor user interface with compressible material construction |
US6535200B2 (en) * | 1999-01-25 | 2003-03-18 | Harald Philipp | Capacitive position sensor |
WO2000044018A1 (en) * | 1999-01-26 | 2000-07-27 | Harald Philipp | Capacitive sensor and array |
US8666495B2 (en) | 1999-03-05 | 2014-03-04 | Metacure Limited | Gastrointestinal methods and apparatus for use in treating disorders and controlling blood sugar |
US8700161B2 (en) | 1999-03-05 | 2014-04-15 | Metacure Limited | Blood glucose level control |
US6730863B1 (en) * | 1999-06-22 | 2004-05-04 | Cirque Corporation | Touchpad having increased noise rejection, decreased moisture sensitivity, and improved tracking |
NO311466B1 (en) * | 1999-10-06 | 2001-11-26 | Oeystein Johnsen | Sensitivity modifier for touch sensitive panels |
WO2001054111A1 (en) | 2000-01-19 | 2001-07-26 | Synaptics, Inc. | Capacitive pointing stick |
US8160864B1 (en) | 2000-10-26 | 2012-04-17 | Cypress Semiconductor Corporation | In-circuit emulator and pod synchronized boot |
US7765095B1 (en) | 2000-10-26 | 2010-07-27 | Cypress Semiconductor Corporation | Conditional branching in an in-circuit emulation system |
US8176296B2 (en) | 2000-10-26 | 2012-05-08 | Cypress Semiconductor Corporation | Programmable microcontroller architecture |
US6724220B1 (en) | 2000-10-26 | 2004-04-20 | Cyress Semiconductor Corporation | Programmable microcontroller architecture (mixed analog/digital) |
US8103496B1 (en) | 2000-10-26 | 2012-01-24 | Cypress Semicondutor Corporation | Breakpoint control in an in-circuit emulation system |
US8149048B1 (en) | 2000-10-26 | 2012-04-03 | Cypress Semiconductor Corporation | Apparatus and method for programmable power management in a programmable analog circuit block |
US7002559B2 (en) * | 2000-11-13 | 2006-02-21 | Anoto Ab | Method, system and product for information management |
US20020084986A1 (en) * | 2001-01-04 | 2002-07-04 | Armstrong Brad A. | Computer mouse with specialized button(s) |
MXPA03010264A (en) * | 2001-05-11 | 2005-03-07 | Shoot The Moon Products Ii Llc | Interactive book reading system using rf scanning circuit. |
US7406674B1 (en) | 2001-10-24 | 2008-07-29 | Cypress Semiconductor Corporation | Method and apparatus for generating microcontroller configuration information |
US8078970B1 (en) | 2001-11-09 | 2011-12-13 | Cypress Semiconductor Corporation | Graphical user interface with user-selectable list-box |
US8042093B1 (en) | 2001-11-15 | 2011-10-18 | Cypress Semiconductor Corporation | System providing automatic source code generation for personalization and parameterization of user modules |
US6971004B1 (en) | 2001-11-19 | 2005-11-29 | Cypress Semiconductor Corp. | System and method of dynamically reconfiguring a programmable integrated circuit |
US7774190B1 (en) | 2001-11-19 | 2010-08-10 | Cypress Semiconductor Corporation | Sleep and stall in an in-circuit emulation system |
US7770113B1 (en) | 2001-11-19 | 2010-08-03 | Cypress Semiconductor Corporation | System and method for dynamically generating a configuration datasheet |
US7844437B1 (en) | 2001-11-19 | 2010-11-30 | Cypress Semiconductor Corporation | System and method for performing next placements and pruning of disallowed placements for programming an integrated circuit |
US8069405B1 (en) | 2001-11-19 | 2011-11-29 | Cypress Semiconductor Corporation | User interface for efficiently browsing an electronic document using data-driven tabs |
US20030214938A1 (en) * | 2002-03-21 | 2003-11-20 | Jindal Deepak Kumar | Method for routing of label switched paths (LSPS) through an internet supporting multi-protocol label switching (MPLS) technology |
US8103497B1 (en) | 2002-03-28 | 2012-01-24 | Cypress Semiconductor Corporation | External interface for event architecture |
US7466307B2 (en) * | 2002-04-11 | 2008-12-16 | Synaptics Incorporated | Closed-loop sensor on a solid-state object position detector |
US7308608B1 (en) | 2002-05-01 | 2007-12-11 | Cypress Semiconductor Corporation | Reconfigurable testing system and method |
US7176897B2 (en) * | 2002-05-17 | 2007-02-13 | 3M Innovative Properties Company | Correction of memory effect errors in force-based touch panel systems |
AU2003232439A1 (en) * | 2002-05-30 | 2003-12-19 | Mattel, Inc. | Interactive multi-sensory reading system electronic teaching/learning device |
US6891531B2 (en) * | 2002-07-05 | 2005-05-10 | Sentelic Corporation | Sensing an object with a plurality of conductors |
US7761845B1 (en) | 2002-09-09 | 2010-07-20 | Cypress Semiconductor Corporation | Method for parameterizing a user module |
WO2004040240A1 (en) * | 2002-10-31 | 2004-05-13 | Harald Philipp | Charge transfer capacitive position sensor |
US7372455B2 (en) | 2003-02-10 | 2008-05-13 | N-Trig Ltd. | Touch detection for a digitizer |
WO2004080533A1 (en) | 2003-03-10 | 2004-09-23 | Impulse Dynamics Nv | Apparatus and method for delivering electrical signals to modify gene expression in cardiac tissue |
US11439815B2 (en) | 2003-03-10 | 2022-09-13 | Impulse Dynamics Nv | Protein activity modification |
US8792985B2 (en) | 2003-07-21 | 2014-07-29 | Metacure Limited | Gastrointestinal methods and apparatus for use in treating disorders and controlling blood sugar |
GB0319714D0 (en) * | 2003-08-21 | 2003-09-24 | Philipp Harald | Anisotropic touch screen element |
US7429976B2 (en) * | 2003-11-24 | 2008-09-30 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Compact pointing device |
US7570247B2 (en) * | 2003-11-24 | 2009-08-04 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Modular assembly for a self-indexing computer pointing device |
US11779768B2 (en) | 2004-03-10 | 2023-10-10 | Impulse Dynamics Nv | Protein activity modification |
US8352031B2 (en) | 2004-03-10 | 2013-01-08 | Impulse Dynamics Nv | Protein activity modification |
US8548583B2 (en) | 2004-03-10 | 2013-10-01 | Impulse Dynamics Nv | Protein activity modification |
US7295049B1 (en) | 2004-03-25 | 2007-11-13 | Cypress Semiconductor Corporation | Method and circuit for rapid alignment of signals |
US7382139B2 (en) * | 2004-06-03 | 2008-06-03 | Synaptics Incorporated | One layer capacitive sensing apparatus having varying width sensing elements |
US7492358B2 (en) * | 2004-06-15 | 2009-02-17 | International Business Machines Corporation | Resistive scanning grid touch panel |
US8069436B2 (en) | 2004-08-13 | 2011-11-29 | Cypress Semiconductor Corporation | Providing hardware independence to automate code generation of processing device firmware |
US8286125B2 (en) | 2004-08-13 | 2012-10-09 | Cypress Semiconductor Corporation | Model for a hardware device-independent method of defining embedded firmware for programmable systems |
US7737953B2 (en) * | 2004-08-19 | 2010-06-15 | Synaptics Incorporated | Capacitive sensing apparatus having varying depth sensing elements |
EP1827571B1 (en) | 2004-12-09 | 2016-09-07 | Impulse Dynamics NV | Protein activity modification |
US7485161B2 (en) * | 2005-01-04 | 2009-02-03 | Air Products And Chemicals, Inc. | Dehydrogenation of liquid fuel in microchannel catalytic reactor |
US7978173B2 (en) * | 2005-01-14 | 2011-07-12 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Pointing device including a moveable puck with mechanical detents |
US7332976B1 (en) | 2005-02-04 | 2008-02-19 | Cypress Semiconductor Corporation | Poly-phase frequency synthesis oscillator |
US20060181511A1 (en) * | 2005-02-09 | 2006-08-17 | Richard Woolley | Touchpad integrated into a key cap of a keyboard for improved user interaction |
US7586480B2 (en) | 2005-02-28 | 2009-09-08 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Hybrid pointing device |
WO2006097934A2 (en) | 2005-03-18 | 2006-09-21 | Metacure Limited | Pancreas lead |
US7504833B1 (en) | 2005-04-01 | 2009-03-17 | Cypress Semiconductor Corporation | Automatically balanced sensing device and method for multiple capacitive sensors |
US7400183B1 (en) | 2005-05-05 | 2008-07-15 | Cypress Semiconductor Corporation | Voltage controlled oscillator delay cell and method |
US8089461B2 (en) | 2005-06-23 | 2012-01-03 | Cypress Semiconductor Corporation | Touch wake for electronic devices |
US8050876B2 (en) * | 2005-07-18 | 2011-11-01 | Analog Devices, Inc. | Automatic environmental compensation of capacitance based proximity sensors |
US7375535B1 (en) | 2005-09-19 | 2008-05-20 | Cypress Semiconductor Corporation | Scan method and topology for capacitive sensing |
US7307485B1 (en) | 2005-11-14 | 2007-12-11 | Cypress Semiconductor Corporation | Capacitance sensor using relaxation oscillators |
US7701440B2 (en) * | 2005-12-19 | 2010-04-20 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Pointing device adapted for small handheld devices having two display modes |
US8085067B1 (en) | 2005-12-21 | 2011-12-27 | Cypress Semiconductor Corporation | Differential-to-single ended signal converter circuit and method |
US7683891B2 (en) * | 2005-12-22 | 2010-03-23 | Synaptics Incorporated | Equalizing reference surface capacitance with uneven thickness |
US7312616B2 (en) | 2006-01-20 | 2007-12-25 | Cypress Semiconductor Corporation | Successive approximate capacitance measurement circuit |
US20070176903A1 (en) * | 2006-01-31 | 2007-08-02 | Dahlin Jeffrey J | Capacitive touch sensor button activation |
US20070200823A1 (en) * | 2006-02-09 | 2007-08-30 | Bytheway Jared G | Cursor velocity being made proportional to displacement in a capacitance-sensitive input device |
US8067948B2 (en) | 2006-03-27 | 2011-11-29 | Cypress Semiconductor Corporation | Input/output multiplexer bus |
US20070235231A1 (en) * | 2006-03-29 | 2007-10-11 | Tekscan, Inc. | Control circuit for sensor array and related methods |
US7591165B2 (en) * | 2006-03-29 | 2009-09-22 | Tekscan Incorporated | Control circuit for sensor array and related methods |
US8144125B2 (en) | 2006-03-30 | 2012-03-27 | Cypress Semiconductor Corporation | Apparatus and method for reducing average scan rate to detect a conductive object on a sensing device |
US8040142B1 (en) | 2006-03-31 | 2011-10-18 | Cypress Semiconductor Corporation | Touch detection techniques for capacitive touch sense systems |
US7721609B2 (en) | 2006-03-31 | 2010-05-25 | Cypress Semiconductor Corporation | Method and apparatus for sensing the force with which a button is pressed |
US20070247446A1 (en) * | 2006-04-25 | 2007-10-25 | Timothy James Orsley | Linear positioning input device |
US8537121B2 (en) | 2006-05-26 | 2013-09-17 | Cypress Semiconductor Corporation | Multi-function slider in touchpad |
US8089472B2 (en) | 2006-05-26 | 2012-01-03 | Cypress Semiconductor Corporation | Bidirectional slider with delete function |
US8619054B2 (en) * | 2006-05-31 | 2013-12-31 | Atmel Corporation | Two dimensional position sensor |
US7825797B2 (en) | 2006-06-02 | 2010-11-02 | Synaptics Incorporated | Proximity sensor device and method with adjustment selection tabs |
US8654083B2 (en) | 2006-06-09 | 2014-02-18 | Apple Inc. | Touch screen liquid crystal display |
US8552989B2 (en) | 2006-06-09 | 2013-10-08 | Apple Inc. | Integrated display and touch screen |
CN104965621B (en) | 2006-06-09 | 2018-06-12 | 苹果公司 | Touch screen LCD and its operating method |
GB0612200D0 (en) * | 2006-06-20 | 2006-08-02 | Philipp Harald | Capacitive position sensor |
US8040321B2 (en) | 2006-07-10 | 2011-10-18 | Cypress Semiconductor Corporation | Touch-sensor with shared capacitive sensors |
US7889176B2 (en) * | 2006-07-18 | 2011-02-15 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Capacitive sensing in displacement type pointing devices |
US7253643B1 (en) | 2006-07-19 | 2007-08-07 | Cypress Semiconductor Corporation | Uninterrupted radial capacitive sense interface |
US9507465B2 (en) * | 2006-07-25 | 2016-11-29 | Cypress Semiconductor Corporation | Technique for increasing the sensitivity of capacitive sensor arrays |
US9766738B1 (en) | 2006-08-23 | 2017-09-19 | Cypress Semiconductor Corporation | Position and usage based prioritization for capacitance sense interface |
US8902173B2 (en) * | 2006-09-29 | 2014-12-02 | Cypress Semiconductor Corporation | Pointing device using capacitance sensor |
US20080088595A1 (en) * | 2006-10-12 | 2008-04-17 | Hua Liu | Interconnected two-substrate layer touchpad capacitive sensing device |
US20080088323A1 (en) * | 2006-10-16 | 2008-04-17 | Emerson Electric Co. | Control and method for a capacitive sensor system |
US8547114B2 (en) | 2006-11-14 | 2013-10-01 | Cypress Semiconductor Corporation | Capacitance to code converter with sigma-delta modulator |
US8089288B1 (en) | 2006-11-16 | 2012-01-03 | Cypress Semiconductor Corporation | Charge accumulation capacitance sensor with linear transfer characteristic |
US8072429B2 (en) * | 2006-12-22 | 2011-12-06 | Cypress Semiconductor Corporation | Multi-axial touch-sensor device with multi-touch resolution |
US7920129B2 (en) | 2007-01-03 | 2011-04-05 | Apple Inc. | Double-sided touch-sensitive panel with shield and drive combined layer |
US8493330B2 (en) | 2007-01-03 | 2013-07-23 | Apple Inc. | Individual channel phase delay scheme |
US9710095B2 (en) | 2007-01-05 | 2017-07-18 | Apple Inc. | Touch screen stack-ups |
US8058937B2 (en) | 2007-01-30 | 2011-11-15 | Cypress Semiconductor Corporation | Setting a discharge rate and a charge rate of a relaxation oscillator circuit |
JP2008262326A (en) * | 2007-04-11 | 2008-10-30 | Matsushita Electric Ind Co Ltd | Touch panel |
US8040266B2 (en) | 2007-04-17 | 2011-10-18 | Cypress Semiconductor Corporation | Programmable sigma-delta analog-to-digital converter |
US8130025B2 (en) | 2007-04-17 | 2012-03-06 | Cypress Semiconductor Corporation | Numerical band gap |
US8092083B2 (en) | 2007-04-17 | 2012-01-10 | Cypress Semiconductor Corporation | Temperature sensor with digital bandgap |
US7737724B2 (en) | 2007-04-17 | 2010-06-15 | Cypress Semiconductor Corporation | Universal digital block interconnection and channel routing |
US8026739B2 (en) | 2007-04-17 | 2011-09-27 | Cypress Semiconductor Corporation | System level interconnect with programmable switching |
US8516025B2 (en) | 2007-04-17 | 2013-08-20 | Cypress Semiconductor Corporation | Clock driven dynamic datapath chaining |
US9564902B2 (en) | 2007-04-17 | 2017-02-07 | Cypress Semiconductor Corporation | Dynamically configurable and re-configurable data path |
US9720805B1 (en) | 2007-04-25 | 2017-08-01 | Cypress Semiconductor Corporation | System and method for controlling a target device |
US8065653B1 (en) | 2007-04-25 | 2011-11-22 | Cypress Semiconductor Corporation | Configuration of programmable IC design elements |
US8266575B1 (en) | 2007-04-25 | 2012-09-11 | Cypress Semiconductor Corporation | Systems and methods for dynamically reconfiguring a programmable system on a chip |
US8144126B2 (en) | 2007-05-07 | 2012-03-27 | Cypress Semiconductor Corporation | Reducing sleep current in a capacitance sensing system |
US7804307B1 (en) | 2007-06-29 | 2010-09-28 | Cypress Semiconductor Corporation | Capacitance measurement systems and methods |
US9500686B1 (en) | 2007-06-29 | 2016-11-22 | Cypress Semiconductor Corporation | Capacitance measurement system and methods |
US8169238B1 (en) * | 2007-07-03 | 2012-05-01 | Cypress Semiconductor Corporation | Capacitance to frequency converter |
US8089289B1 (en) | 2007-07-03 | 2012-01-03 | Cypress Semiconductor Corporation | Capacitive field sensor with sigma-delta modulator |
WO2009006556A1 (en) | 2007-07-03 | 2009-01-08 | Cypress Semiconductor Corporation | Normalizing capacitive sensor array signals |
US8570053B1 (en) | 2007-07-03 | 2013-10-29 | Cypress Semiconductor Corporation | Capacitive field sensor with sigma-delta modulator |
WO2009023880A2 (en) * | 2007-08-15 | 2009-02-19 | Frederick Johannes Bruwer | Grid touch position determination |
US20090058802A1 (en) * | 2007-08-27 | 2009-03-05 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Input device |
US8232963B2 (en) * | 2007-08-27 | 2012-07-31 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Control and data entry apparatus |
US8049569B1 (en) | 2007-09-05 | 2011-11-01 | Cypress Semiconductor Corporation | Circuit and method for improving the accuracy of a crystal-less oscillator having dual-frequency modes |
US8633915B2 (en) | 2007-10-04 | 2014-01-21 | Apple Inc. | Single-layer touch-sensitive display |
US8125465B2 (en) * | 2007-10-19 | 2012-02-28 | Chimei Innolux Corporation | Image displaying systems |
US7978175B2 (en) * | 2007-11-23 | 2011-07-12 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Magnetic re-centering mechanism for a capacitive input device |
US20090135157A1 (en) * | 2007-11-27 | 2009-05-28 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Capacitive Sensing Input Device with Reduced Sensitivity to Humidity and Condensation |
US9372576B2 (en) * | 2008-01-04 | 2016-06-21 | Apple Inc. | Image jaggedness filter for determining whether to perform baseline calculations |
US20090174676A1 (en) * | 2008-01-04 | 2009-07-09 | Apple Inc. | Motion component dominance factors for motion locking of touch sensor data |
US8525798B2 (en) | 2008-01-28 | 2013-09-03 | Cypress Semiconductor Corporation | Touch sensing |
US8487912B1 (en) | 2008-02-01 | 2013-07-16 | Cypress Semiconductor Corporation | Capacitive sense touch device with hysteresis threshold |
US8358142B2 (en) | 2008-02-27 | 2013-01-22 | Cypress Semiconductor Corporation | Methods and circuits for measuring mutual and self capacitance |
US8319505B1 (en) | 2008-10-24 | 2012-11-27 | Cypress Semiconductor Corporation | Methods and circuits for measuring mutual and self capacitance |
US9104273B1 (en) | 2008-02-29 | 2015-08-11 | Cypress Semiconductor Corporation | Multi-touch sensing method |
JP4508248B2 (en) * | 2008-03-03 | 2010-07-21 | ソニー株式会社 | Input device and electronic device |
TWI383310B (en) | 2008-03-14 | 2013-01-21 | Tpo Displays Corp | Control method, circuit, and electronic system utilizing the same |
US8248383B2 (en) | 2008-04-24 | 2012-08-21 | Integrated Device Technology, Inc. | Multi-touch touch screen with single-layer ITO bars arranged in parallel |
US20110169768A1 (en) * | 2008-07-08 | 2011-07-14 | Kenichi Matsushima | Electrostatic detection device, information apparatus, and electrostatic detection method |
TWI375166B (en) * | 2008-07-15 | 2012-10-21 | Tpo Displays Corp | Systems for displaying images |
US8482536B1 (en) | 2008-07-23 | 2013-07-09 | Cypress Semiconductor Corporation | Compensation of signal values for a touch sensor |
US20100045625A1 (en) * | 2008-08-21 | 2010-02-25 | Tpo Displays Corp. | Touch panel and system for displaying images utilizing the same |
KR20110067039A (en) * | 2008-09-24 | 2011-06-20 | 쓰리엠 이노베이티브 프로퍼티즈 컴파니 | Mutual capacitance measuring circuits and methods |
TWI387908B (en) * | 2008-09-25 | 2013-03-01 | Tpo Displays Corp | Device and method for detecting position of object and image display system using the same device |
US8614690B2 (en) * | 2008-09-26 | 2013-12-24 | Apple Inc. | Touch sensor panel using dummy ground conductors |
US9927924B2 (en) * | 2008-09-26 | 2018-03-27 | Apple Inc. | Differential sensing for a touch panel |
US8321174B1 (en) | 2008-09-26 | 2012-11-27 | Cypress Semiconductor Corporation | System and method to measure capacitance of capacitive sensor array |
US8487639B1 (en) | 2008-11-21 | 2013-07-16 | Cypress Semiconductor Corporation | Receive demodulator for capacitive sensing |
US8274486B2 (en) * | 2008-12-22 | 2012-09-25 | Flextronics Ap, Llc | Diamond pattern on a single layer |
US8922521B2 (en) | 2009-02-02 | 2014-12-30 | Apple Inc. | Switching circuitry for touch sensitive display |
US20100224821A1 (en) * | 2009-03-04 | 2010-09-09 | Bae Systems Information And Electronic Systems Integration Inc. | Nanostructure having metal nanoparticles and a method of assembly thereof |
US8866500B2 (en) | 2009-03-26 | 2014-10-21 | Cypress Semiconductor Corporation | Multi-functional capacitance sensing circuit with a current conveyor |
US8174510B2 (en) | 2009-03-29 | 2012-05-08 | Cypress Semiconductor Corporation | Capacitive touch screen |
US8593410B2 (en) | 2009-04-10 | 2013-11-26 | Apple Inc. | Touch sensor panel design |
JP5446426B2 (en) * | 2009-04-24 | 2014-03-19 | パナソニック株式会社 | Position detection device |
US9448964B2 (en) | 2009-05-04 | 2016-09-20 | Cypress Semiconductor Corporation | Autonomous control in a programmable system |
CN105424067B (en) * | 2009-05-13 | 2019-04-09 | 辛纳普蒂克斯公司 | Capacitive sensor means |
JP5178631B2 (en) * | 2009-05-26 | 2013-04-10 | 株式会社ジャパンディスプレイウェスト | Touch sensor, display device, and electronic device |
BRPI1004217A2 (en) * | 2009-06-29 | 2016-02-23 | Sony Corp | capacitive touch panel and display device |
US8957874B2 (en) | 2009-06-29 | 2015-02-17 | Apple Inc. | Touch sensor panel design |
KR101085403B1 (en) * | 2009-07-21 | 2011-11-21 | 주식회사 코아리버 | Method and apparatus for sensing proximity touch |
US8456443B2 (en) | 2009-07-24 | 2013-06-04 | Synaptics Incorporated | Single-layer touch sensors |
US20110018829A1 (en) * | 2009-07-24 | 2011-01-27 | Cypress Semiconductor Corporation | Mutual capacitance sensing array |
US9753597B2 (en) | 2009-07-24 | 2017-09-05 | Cypress Semiconductor Corporation | Mutual capacitance sensing array |
US8723827B2 (en) | 2009-07-28 | 2014-05-13 | Cypress Semiconductor Corporation | Predictive touch surface scanning |
FR2949007B1 (en) | 2009-08-07 | 2012-06-08 | Nanotec Solution | DEVICE AND METHOD FOR CONTROL INTERFACE SENSITIVE TO A MOVEMENT OF A BODY OR OBJECT AND CONTROL EQUIPMENT INCORPORATING THIS DEVICE. |
TWI464625B (en) | 2009-10-09 | 2014-12-11 | Egalax Empia Technology Inc | Method and device for analyzing positions |
US8643613B2 (en) | 2009-10-09 | 2014-02-04 | Egalax—Empia Technology Inc. | Method and device for dual-differential sensing |
WO2011041942A1 (en) * | 2009-10-09 | 2011-04-14 | 禾瑞亚科技股份有限公司 | Method and device for detecting position |
TWI566135B (en) | 2009-10-09 | 2017-01-11 | 禾瑞亞科技股份有限公司 | Method and device for dual-differential sensing |
US8941597B2 (en) | 2009-10-09 | 2015-01-27 | Egalax—Empia Technology Inc. | Method and device for analyzing two-dimension sensing information |
US9864471B2 (en) | 2009-10-09 | 2018-01-09 | Egalax_Empia Technology Inc. | Method and processor for analyzing two-dimension information |
US9689906B2 (en) * | 2009-10-09 | 2017-06-27 | Egalax_Empia Technology Inc. | Method and device for position detection |
CN102043525B (en) | 2009-10-09 | 2013-01-09 | 禾瑞亚科技股份有限公司 | Method and apparatus for converting sensing information |
US8558802B2 (en) * | 2009-11-21 | 2013-10-15 | Freescale Semiconductor, Inc. | Methods and apparatus for performing capacitive touch sensing and proximity detection |
US8934975B2 (en) | 2010-02-01 | 2015-01-13 | Metacure Limited | Gastrointestinal electrical therapy |
WO2011122346A1 (en) | 2010-03-29 | 2011-10-06 | シャープ株式会社 | Display device having touch panel functionality |
US9164620B2 (en) | 2010-06-07 | 2015-10-20 | Apple Inc. | Touch sensing error compensation |
CN102314268B (en) * | 2010-06-30 | 2013-05-29 | 盛群半导体股份有限公司 | Capacitance-type touch device |
KR101292733B1 (en) * | 2010-10-18 | 2013-08-05 | 주식회사 포인칩스 | Multi-touch panels capacitance sensing circuitry |
CN102479009A (en) * | 2010-11-29 | 2012-05-30 | 苏州华芯微电子股份有限公司 | Method for updating background value of capacitance touch tablet |
US8804056B2 (en) | 2010-12-22 | 2014-08-12 | Apple Inc. | Integrated touch screens |
EP2474886A1 (en) * | 2011-01-05 | 2012-07-11 | Research In Motion Limited | Electronic device and method of controlling same |
CN102722297B (en) * | 2011-03-30 | 2016-01-13 | 中兴通讯股份有限公司 | A kind of touch panel device and the method realized close to induction thereof |
US9268441B2 (en) | 2011-04-05 | 2016-02-23 | Parade Technologies, Ltd. | Active integrator for a capacitive sense array |
FR2976688B1 (en) | 2011-06-16 | 2021-04-23 | Nanotec Solution | DEVICE AND METHOD FOR GENERATING AN ELECTRICAL POWER SUPPLY IN AN ELECTRONIC SYSTEM WITH A VARIABLE REFERENCE POTENTIAL. |
FR2985049B1 (en) | 2011-12-22 | 2014-01-31 | Nanotec Solution | CAPACITIVE MEASURING DEVICE WITH SWITCHED ELECTRODES FOR TOUCHLESS CONTACTLESS INTERFACES |
TWI486847B (en) * | 2012-03-15 | 2015-06-01 | 義隆電子股份有限公司 | Scan method of touch panel to increase frame rate and touch panel using the same |
US9329723B2 (en) | 2012-04-16 | 2016-05-03 | Apple Inc. | Reconstruction of original touch image from differential touch image |
KR101278121B1 (en) * | 2012-04-17 | 2013-07-11 | 주식회사 리딩유아이 | Apparatus for sensing a capacitance for a multi-touch panel and multi-touch sensing device having the same |
US9733293B1 (en) * | 2012-09-21 | 2017-08-15 | Qualcomm Incorporated | Differential pixel test for capacitive touch screens |
EP2926226B1 (en) | 2012-11-27 | 2019-02-06 | Microsoft Technology Licensing, LLC | Detection with a capacitive based digitizer sensor |
US20140201685A1 (en) | 2013-01-14 | 2014-07-17 | Darren Lim | User input determination |
US9336723B2 (en) | 2013-02-13 | 2016-05-10 | Apple Inc. | In-cell touch for LED |
EP2772837A1 (en) | 2013-02-28 | 2014-09-03 | Nxp B.V. | Touch sensor for smartcard |
US9552089B2 (en) | 2013-08-07 | 2017-01-24 | Synaptics Incorporated | Capacitive sensing using a matrix electrode pattern |
US10042446B2 (en) | 2013-08-13 | 2018-08-07 | Samsung Electronics Company, Ltd. | Interaction modes for object-device interactions |
US10108305B2 (en) | 2013-08-13 | 2018-10-23 | Samsung Electronics Company, Ltd. | Interaction sensing |
US9886141B2 (en) | 2013-08-16 | 2018-02-06 | Apple Inc. | Mutual and self capacitance touch measurements in touch panel |
US9274662B2 (en) | 2013-10-18 | 2016-03-01 | Synaptics Incorporated | Sensor matrix pad for performing multiple capacitive sensing techniques |
WO2015088629A1 (en) | 2013-12-13 | 2015-06-18 | Pylemta Management Llc | Integrated touch and display architectures for self-capacitive touch sensors |
US10133382B2 (en) | 2014-05-16 | 2018-11-20 | Apple Inc. | Structure for integrated touch screen |
US10936120B2 (en) | 2014-05-22 | 2021-03-02 | Apple Inc. | Panel bootstraping architectures for in-cell self-capacitance |
US10289251B2 (en) | 2014-06-27 | 2019-05-14 | Apple Inc. | Reducing floating ground effects in pixelated self-capacitance touch screens |
US9504620B2 (en) | 2014-07-23 | 2016-11-29 | American Sterilizer Company | Method of controlling a pressurized mattress system for a support structure |
US10444862B2 (en) | 2014-08-22 | 2019-10-15 | Synaptics Incorporated | Low-profile capacitive pointing stick |
US9880655B2 (en) | 2014-09-02 | 2018-01-30 | Apple Inc. | Method of disambiguating water from a finger touch on a touch sensor panel |
EP3175330B1 (en) | 2014-09-22 | 2022-04-20 | Apple Inc. | Ungrounded user signal compensation for pixelated self-capacitance touch sensor panel |
CN107077262B (en) | 2014-10-27 | 2020-11-10 | 苹果公司 | Pixelization from capacitive water repellence |
WO2016072983A1 (en) | 2014-11-05 | 2016-05-12 | Onamp Research Llc | Common electrode driving and compensation for pixelated self-capacitance touch screen |
US9354720B1 (en) | 2014-12-23 | 2016-05-31 | Synaptics Incorporated | Low-profile capacitive pointing stick |
US10990148B2 (en) | 2015-01-05 | 2021-04-27 | Synaptics Incorporated | Central receiver for performing capacitive sensing |
CN111610890A (en) | 2015-02-02 | 2020-09-01 | 苹果公司 | Flexible self-capacitance and mutual capacitance touch sensing system architecture |
US10488992B2 (en) | 2015-03-10 | 2019-11-26 | Apple Inc. | Multi-chip touch architecture for scalability |
US10146359B2 (en) | 2015-04-28 | 2018-12-04 | Apple Inc. | Common electrode auto-compensation method |
US9898095B2 (en) | 2015-06-29 | 2018-02-20 | Synaptics Incorporated | Low-profile capacitive pointing stick |
CN105091914B (en) * | 2015-06-29 | 2018-04-10 | 林基焜 | Detection means and detection method |
US9715304B2 (en) | 2015-06-30 | 2017-07-25 | Synaptics Incorporated | Regular via pattern for sensor-based input device |
US9720541B2 (en) | 2015-06-30 | 2017-08-01 | Synaptics Incorporated | Arrangement of sensor pads and display driver pads for input device |
US10386962B1 (en) | 2015-08-03 | 2019-08-20 | Apple Inc. | Reducing touch node electrode coupling |
US10365773B2 (en) | 2015-09-30 | 2019-07-30 | Apple Inc. | Flexible scan plan using coarse mutual capacitance and fully-guarded measurements |
EP3361978A4 (en) | 2015-10-16 | 2019-05-29 | Dalhousie University | Systems and methods for monitoring patient motion via capacitive position sensing |
US10067587B2 (en) | 2015-12-29 | 2018-09-04 | Synaptics Incorporated | Routing conductors in an integrated display device and sensing device |
CN109564485B (en) | 2016-07-29 | 2022-04-01 | 苹果公司 | Touch sensor panel with multi-power domain chip configuration |
AU2017208277B2 (en) | 2016-09-06 | 2018-12-20 | Apple Inc. | Back of cover touch sensors |
US10642418B2 (en) | 2017-04-20 | 2020-05-05 | Apple Inc. | Finger tracking in wet environment |
US11537229B2 (en) * | 2019-01-17 | 2022-12-27 | Beijing Taifang Technology Co., Ltd. | Touch pad pressure detection method and apparatus, storage medium and computer device |
US11157109B1 (en) | 2019-09-06 | 2021-10-26 | Apple Inc. | Touch sensing with water rejection |
US11662867B1 (en) | 2020-05-30 | 2023-05-30 | Apple Inc. | Hover detection on a touch sensor panel |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0574213A1 (en) * | 1992-06-08 | 1993-12-15 | Synaptics, Incorporated | Object position detector |
EP0609021A2 (en) * | 1993-01-29 | 1994-08-03 | AT&T Corp. | Capacitive position sensor |
-
1994
- 1994-09-02 US US08/300,387 patent/US5914465A/en not_active Expired - Lifetime
-
1995
- 1995-09-01 JP JP50961496A patent/JP3526577B2/en not_active Expired - Lifetime
- 1995-09-01 WO PCT/US1995/011180 patent/WO1996007981A1/en active IP Right Grant
- 1995-09-01 CN CNB951958119A patent/CN1153173C/en not_active Expired - Lifetime
- 1995-09-01 EP EP95932385A patent/EP0777888B1/en not_active Expired - Lifetime
- 1995-09-01 KR KR1019970701215A patent/KR100274772B1/en not_active IP Right Cessation
- 1995-09-01 AU AU35444/95A patent/AU3544495A/en not_active Abandoned
- 1995-09-01 DE DE69527295T patent/DE69527295T2/en not_active Expired - Lifetime
-
1998
- 1998-03-05 HK HK98101835A patent/HK1002568A1/en not_active IP Right Cessation
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0574213A1 (en) * | 1992-06-08 | 1993-12-15 | Synaptics, Incorporated | Object position detector |
US5374787A (en) * | 1992-06-08 | 1994-12-20 | Synaptics, Inc. | Object position detector |
EP0609021A2 (en) * | 1993-01-29 | 1994-08-03 | AT&T Corp. | Capacitive position sensor |
Cited By (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9081426B2 (en) | 1992-03-05 | 2015-07-14 | Anascape, Ltd. | Image controller |
US9098142B2 (en) | 1998-01-26 | 2015-08-04 | Apple Inc. | Sensor arrangement for use with a touch sensor that identifies hand parts |
US8902175B2 (en) | 1998-01-26 | 2014-12-02 | Apple Inc. | Contact tracking and identification module for touch sensing |
US9298310B2 (en) | 1998-01-26 | 2016-03-29 | Apple Inc. | Touch sensor contact information |
US8866752B2 (en) | 1998-01-26 | 2014-10-21 | Apple Inc. | Contact tracking and identification module for touch sensing |
US9329717B2 (en) | 1998-01-26 | 2016-05-03 | Apple Inc. | Touch sensing with mobile sensors |
US9001068B2 (en) | 1998-01-26 | 2015-04-07 | Apple Inc. | Touch sensor contact information |
JP2012113761A (en) * | 1998-01-26 | 2012-06-14 | Wayne Westerman | Method for integrating manual operation inputs |
US9342180B2 (en) | 1998-01-26 | 2016-05-17 | Apple Inc. | Contact tracking and identification module for touch sensing |
US9804701B2 (en) | 1998-01-26 | 2017-10-31 | Apple Inc. | Contact tracking and identification module for touch sensing |
US9626032B2 (en) | 1998-01-26 | 2017-04-18 | Apple Inc. | Sensor arrangement for use with a touch sensor |
JP2007242035A (en) * | 1998-01-26 | 2007-09-20 | Wayne Westerman | Multi-touch surface device |
US9348452B2 (en) | 1998-01-26 | 2016-05-24 | Apple Inc. | Writing using a touch sensor |
US9383855B2 (en) | 1998-01-26 | 2016-07-05 | Apple Inc. | Identifying contacts on a touch surface |
US9448658B2 (en) | 1998-01-26 | 2016-09-20 | Apple Inc. | Resting contacts |
US9552100B2 (en) | 1998-01-26 | 2017-01-24 | Apple Inc. | Touch sensing with mobile sensors |
EP2506130A1 (en) * | 2009-10-09 | 2012-10-03 | Egalax_Empia Technology Inc. | Method and device for capacitive detecting position |
EP2506130A4 (en) * | 2009-10-09 | 2014-07-30 | Egalax Empia Technology Inc | Method and device for capacitive detecting position |
Also Published As
Publication number | Publication date |
---|---|
AU3544495A (en) | 1996-03-27 |
DE69527295D1 (en) | 2002-08-08 |
HK1002568A1 (en) | 1998-09-04 |
DE69527295T2 (en) | 2002-10-17 |
CN1164286A (en) | 1997-11-05 |
KR100274772B1 (en) | 2000-12-15 |
JP3526577B2 (en) | 2004-05-17 |
EP0777888B1 (en) | 2002-07-03 |
US5914465A (en) | 1999-06-22 |
CN1153173C (en) | 2004-06-09 |
EP0777888A1 (en) | 1997-06-11 |
JPH10505183A (en) | 1998-05-19 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0777888B1 (en) | Object position detector | |
US5861583A (en) | Object position detector | |
US5543590A (en) | Object position detector with edge motion feature | |
US6239389B1 (en) | Object position detection system and method | |
US5488204A (en) | Paintbrush stylus for capacitive touch sensor pad | |
US5889236A (en) | Pressure sensitive scrollbar feature | |
EP1607852B1 (en) | Object position detector with edge motion feature and gesture recognition | |
US5374787A (en) | Object position detector | |
US6610936B2 (en) | Object position detector with edge motion feature and gesture recognition | |
US7911456B2 (en) | Object position detector with edge motion feature and gesture recognition | |
US7532205B2 (en) | Object position detector with edge motion feature and gesture recognition |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WWE | Wipo information: entry into national phase |
Ref document number: 95195811.9 Country of ref document: CN |
|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AM AT AU BB BG BR BY CA CH CN CZ DE DK EE ES FI GB GE HU IS JP KE KG KP KR KZ LK LR LT LU LV MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK TJ TM TT UA UG US UZ VN |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN ML MR NE SN TD TG |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
WWE | Wipo information: entry into national phase |
Ref document number: 1995932385 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 1019970701215 Country of ref document: KR |
|
WWP | Wipo information: published in national office |
Ref document number: 1995932385 Country of ref document: EP |
|
REG | Reference to national code |
Ref country code: DE Ref legal event code: 8642 |
|
WWP | Wipo information: published in national office |
Ref document number: 1019970701215 Country of ref document: KR |
|
WWG | Wipo information: grant in national office |
Ref document number: 1019970701215 Country of ref document: KR |
|
WWG | Wipo information: grant in national office |
Ref document number: 1995932385 Country of ref document: EP |