WO2012124455A1

WO2012124455A1 - Input device

Info

Publication number: WO2012124455A1
Application number: PCT/JP2012/054670
Authority: WO
Inventors: Yusuke Shimizu; Kei Nakamura; Akito NINOMIYA
Original assignee: Nitto Denko Corporation
Priority date: 2011-03-14
Filing date: 2012-02-17
Publication date: 2012-09-20

Abstract

An input device is provided which records the movement path of a conventional writing implement to store the movement path as electronic data by merely writing a note directly on a paper sheet placed within a frame with the conventional writing implement. The input device includes an optical sensor including a rectangular frame, and at least one pair of light-emitting and light-receiving elements. The optical sensor senses the interception of light beams traveling from the light-emitting element to the light-receiving element which is caused in association with the writing implement within the frame to thereby output information on the position of the writing implement within the frame. When a writing operation is performed on part of a paper sheet revealed within the frame of the optical sensor with a writing implement, the movement path of a tip of the writing implement is stored as electronic data in a storage means provided in this input device or in a storage means provided outside the device.

Description

INPUT DEVICE

Technical Field

The present invention relates to an input device including an optical position detecting means.

Background Art

Flat input devices such as tablets and touch panels have been used as input devices that allow anyone to easily operate information devices such as computers, in place of keyboards, mice and the like the operation of which requires getting used to. Such a flat input device includes a touch position detecting means for detecting the touch position of a finger of a person who operates a device or a pen on a touch panel and the like two-dimensionally (in x- and y-directions ) , and allows a user to intuitively operate the aforementioned information devices and the like in cooperation with displays (pictorial patterns, icons and the like) produced on a flat display such as a monitor and a liquid crystal screen disposed under the panel of the monitor (see, for example, Japanese Published Patent Application No.2004-206613) .

Conventionally, touch position detecting means employing a resistive method, a capacitive method, an electromagnetic induction method and the like are used as the touch position detecting means (touch sensor) for use in the aforementioned touch panel and the like from the viewpoints of costs, performance, durability and the like. The touch panel based on. these methods has a structure such that a large number of electrical contacts arranged in a matrix are formed near the surface of the panel .

On the other hand, there are instances wherein the configuration of the tablets, the touch panels and the like as mentioned above is applied to a virtual electronic stationery. For example, an electronic notepad device which converts handwritten notes and the like into digital form (into images) includes a display (touch panel) with a touch sensor which is capable of displaying inputted notes and the like thereon. By bringing a finger, a purpose-built stylus and the like into contact with the display and then moving the tip thereof, the movement path of the tip of the finger and the like or handwriting (position information) is inputted as information such as a note to appear on the aforementioned display and the like. Also, the movement path of the tip appearing on the aforementioned display and the like is stored as electronic data such as an image in the aforementioned electronic notepad device.

Summary of Invention

The electronic notepad device as mentioned above is convenient because a user can easily enter characters and the like thereinto. However, there is still a strong demand mainly from users unskilled in the manipulation of computers, electronic information devices and the like and from elderly people to leave notes so that their handwriting is left directly on media such as paper sheets, rather than such electronic notes that their handwriting, characters and the like appear on a display and the like.

An input device is provided which records the movement path of a conventional writing implement and the like to store the movement path as electronic data by merely writing a note and the like directly on a paper sheet placed within a frame with the conventional writing implement .

The input device comprises a frame-shaped optical sensor capable of surrounding at least part of a paper sheet capable of being written upon by a writing implement , the optical sensor including a rectangular frame, and at least one pair of light-emitting and light-receiving elements mounted to the rectangular frame, the optical sensor sensing the interception of light beams traveling from the light-emitting element to the light-receiving element which is caused in association with the tip of the writing implement within the frame to thereby output information on the position of the tip of writing implement within the frame; and a storage means for storing therein the movement path of the' tip of the writing implement as electronic data when a writing operation is performed on part of the paper sheet revealed within the frame of the optical sensor with the writing implement.

The input device is placed on a paper sheet for writing, and includes the aforementioned frame-shaped optical sensor having the frame within which at least part of the paper sheet is revealed, and the storage means for storing therein movement path information on the writing implement provided from this optical sensor as electronic data. Thus, when the writing operation is performed on part of the paper sheet revealed within the frame of the aforementioned optical sensor with the writing implement and the like, the path (handwriting) is left on the aforementioned paper sheet, and is stored as electronic data in the aforementioned storage means. This enables the input device to automatically convert the movement path of the writing implement by merely writing a note and the like directly on the paper sheet placed within the frame with the conventional writing implement without giving special consideration to the conversion into electronic form. Also, the

aforementioned information in electronic form may be taken (reproduced) from the aforementioned storage means by the use of a computer and the like. The sharing of the information with others and the storing of knowledge, records and the like are accomplished easily. This provides convenience.

The input device includes, as a means (optical sensor) for detecting the touch position of the tip of the writing implement, the optical sensor including the rectangular frame, and the at least one pair of light-emitting and light-receiving elements mounted to the rectangular frame, the optical sensor sensing the interception of light beams traveling from the light-emitting element to the light-receiving element which is caused in association with the tip of the writing implement within the frame to thereby output information on the position of the tip of the writing implement within the frame. The surface for the detection of the touch position has no electrical (physical) contacts. The input device therefore has high durability, and is less susceptible to dust, contamination, and the like.

Additionally, a high writing pressure as in a resistive method, a capacitive method, an electromagnet ic induction method and the like is not required during the writing operation with a writing implement. Thus, the writing operation is performed in a natural manner without concern for the sensor.

There are cases where the aforementioned frame-shaped optical sensor is an optical sensor such that an optical waveguide including a plurality of light-emitting cores and a plurality of light-receiving cores is provided in a frame portion of the frame-shaped optical sensor including first and second sections opposed to each other in the form of the frame, the light-emitting cores being formed in the first section, the light-receiving cores being formed in the second section, the cores having respective tips positioned on inner edges of the frame so that the tips of the light-emitting cores and the tips of the light-receiving cores are opposed to each other, and such that light beams emitted from the light-emitting cores of the optical waveguide toward the light-receiving cores thereof produce a lattice of vertical and horizontal light beams crossing each other within the frame. In such cases, the frame of this optical sensor may be of a thin configuration. Specifically, the optical waveguide may be made thin, for example in film form or in sheet form. This allows the frame to be made so thin as not to serve as an impediment to the writing operation with the writing implement even when the optical waveguide is incorporated in the frame of this optical sensor. Thus, a user can perform the writing operation on the paper sheet in a more natural manner and in a comfortable position.

There are cases where the aforementioned frame-shaped optical sensor in the input device is an optical sensor such that: the frame of the frame-shaped optical sensor includes first and second sections opposed to each other in the form of the frame; light-emitting elements are arranged in the first section and light-receiving elements are arranged in the second section; the light-emitting elements and the

light-receiving elements are positioned to face interior of the frame; and light beams emitted from the light-emitting elements toward the light-receiving elements produce a lattice of vertical and horizontal light beams crossing each other within the frame. In such cases, general-purpose components may be used, for example, light-emitting diodes (LEDs) serving as the light-emitting elements ( a light source ) and photodiodes (PDs) serving as the light-receiving elements. This advantageously allows the formation of the aforementioned optical sensor at low costs. Additional advantages lie in high impact resistance and in high durability. There are cases where the aforementioned frame-shaped optical sensor in the input device is an optical sensor such that: modules each including a light-receiving element array composed of a plurality of light-receiving elements and the light-emitting element in vertically stacked relation are disposed on two corners, respectively, on opposite ends of one side among the four sides of the frame of the frame-shaped optical sensor; a tape-like retroreflector is provided on the inner side surface of three sides other than the one side lying between the modules; and light beams emitted from the light-emitting element of one of the modules are reflected from the retroreflector to travel back into the light-receiving element array of the one module. In "such cases, the position of the tip of the aforementioned input element is specified by triangulation through the use of a small number of components. This input device is also formed at low costs by using general-purpose components .

In the input device, there- are cases where the optical sensor and the storage means are formed integrally as a storage device, and the storage device is placeable on or removable from the paper sheet. In such cases, the aforementioned paper sheet is easily replaceable with a new one. Even when the paper sheet is replaced with a new one, the aforementioned stored information (movement path) may be easily taken (reproduced) from the storage means of the aforementioned storage device by the use of a computer and the like.

Brief Description of Drawings

FIG. 1 is view illustrating an overall configuration of an input device according to an embodiment .

FIG.2 is a view schematically illustrating storage means used for the input device according to a different embodiment .

FIG. 3 is a pian view illustrating a schematic configuration of the input device according to a first embodiment .

FIG. 4 is a plan view illustrating a schematic configuration of the input device according to a second embodiment .

FIG. 5(a) is a plan view illustrating a schematic configuration of the input device according to a third embodiment, and (b) is an enlarged view of a portion indicated by Z thereof.

FIGS. 6(a) to (f) are views illustrating a method of manufacturing optical waveguides for use in the input device according to the first embodiment. Description of Embodiments

Next, embodiments according to the present invention will now be described in detail with reference to the drawings.

FIG. 1 is view illustrating an overall configuration of an input device D according to an embodiment .

This input device D includes a frame-shaped optical sensor S surrounding at least part of a paper sheet P capable of being written upon by a writing implement W, and a storage means M for storing the movement path of the tip of the writing implement W within the frame of the optical sensor S as electronic data. The

aforementioned optical sensor S includes a rectangular frame 1, and at least one pair of light-emitting (light source) and light-receiving elements mounted to this frame 1. The optical sensor S senses the interception of light beams traveling from the aforementioned light-emitting element to the light-receiving element which is caused in association with the writing implement W within the aforementioned frame 1 to thereby output information on the position of the aforementioned writ ing implement W and the like within the frame 1.

The aforementioned input device D incorporates a communication (power) cable (optional), a battery for driving the communication (power) cable, a control means such as a driver for the aforementioned light-emitting element and the light-receiving element, and a communication means (wired or wireless ) for communicating with information devices such as computers, all of which are not shown. In the aforementioned instance, the information on the position of the writing implement W and the like detected by the aforementioned optical sensor S is stored in the storage means M provided in contact with this optical sensor S. The input device D in which the aforementioned optical sensor S and the storage means M (in some cases, incorporated in the frame 1) are integral with each other is referred to as a "storage device" in some cases .

Next, an instance in which the storage (storage means) of the information on the position of the writing implement W and the like detected by the input device D is performed using external devices, networks and the like will be described. FIG. 2 is a view schematically illustrating storage means used for the input device D according to a different embodiment.

The input device D according to this different embodiment also includes the frame-shaped optical sensor S surrounding at least part of the paper sheet P, and a storage means for storing the movement path of the tip of the writing implement W as electronic data. The aforementioned optical sensor S senses the interception of light beams which is caused in association with the writing implement W and the like within the frame 1 to thereby output information on the position of the aforementioned writing implement W and the like within the frame 1.

The input device D according to the aforementioned different embodiment is capable of storing (recording) the information on the position of the aforementioned writing implement W and the like as electronic data in various external devices and on networks, as shown in FIG. 2.

The aforementioned different embodiment will be described in detail. When, for example, a flash memory such as a USB memory device UM or a memory card SD in the figure is usedas the storagemeans, the aforementioned flash memory is connected to a slot, a connector and the like provided in a side surface and the like of this input device D to thereby store therein the information on the position of the aforementioned writing implement W and the like as electronic data. The aforementioned recorded information may be taken (reproduced) from the aforementioned storage means by the use of a computer and the like. The sharing of information with others and the storing of knowledge, records and the like are accomplished easily. Various card-type media such as SD, MMC , MS, SM, xD and CFmay be used as the aforementioned memory card (SD) .

When a desktop computer DT and a laptop computer LT (including a notebook-sized PC, a netbook PC, a tablet PC and the like) in the figure are used as the aforementioned storage means, this input device D and each of the aforementioned computers DT and LT may be connected for communication with each other either wiredly (through a cable L and the like) or wirelessly (through a wireless LAN, BLUETOOTH®, and the like) . This enables a storage device incorporated in each of the aforementioned computers DT and LT to store therein the information on the position of the aforementioned writing implement W and the like as electronic data.

When the information on the position is stored in the aforementioned computers DT and LT, these computers DT and LT may be used to reproduce the aforementioned information immediately. The storage device (storage medium) used herein may include optical media such as a CD, a DVD and a BD, in addition to storages such as a HDD and an SSD. Further, a flash memory (with reference to the above) and the like connected to the aforementioned computers DT and LT may be used. Further, when the input device D is wiredly connected to the aforementioned computers DT and LT, power required for operation may be supplied from the computers DT and LT to the aforementioned input device D.

When a portable information device such as a tablet (pad) device TD in the figure, a PDA (a personal digital assistant PD) and an electronic dictionary is used as the aforementioned storage means, the input device D and the portable information device may be connected for communication with each other either wiredly (not shown) or wirelessly in a manner similar to that described above. This enables a storage device incorporated in each of the aforementioned portable information devices to store therein the information on the position of the aforementioned writing implement W and the like as electronic data. When the information on the position is stored in the aforementioned portable information devices, a display device in these devices may be used to reproduce the aforementioned information immediately. The storage device (storage medium) used herein may include, in addition to storages such as a flash memory and an SSD incorporated in the aforementioned portable information devices and a microdrive, a memory card (with reference to the above) connected to these storages. Further, when the input device D is wiredly connected to the aforementioned portable information devices, power required for operation may be supplied from the portable information devices to the aforementioned input device D.

When a portable communication device such as a cellular mobile phone MF and a smartphone SF in the figure is used as the aforementioned storage means, the input device D and the portable communication device may be connected for communication with each other either wiredly (not shown) or wirelessly in a manner similar to that described above. This enables a storage device in each of the aforementioned portable communication devices to store therein the information on the position of the aforementioned writing implement W and the like as electronic data. When the information on the position is stored in the aforementioned portable communication devices, a display device in these devices may be used to reproduce the aforementioned information immediately. The storage device (storage medium) used herein may include, in addition to storages such as a flash memory incorporated in the aforementioned portable

communication devices, a memory card (with reference to the above) connected to (inserted in) these storages.

When the various external information devices (the computers, the portable information devices , the portable communication devices and the like) communicating with the input device D are connected to a communication or information network as shown in FIG. 2, the information on the position of the aforementioned writing implement W and the like may be stored via these information devices to a server SV and the like on a cloud computing system (or a network computing system) . Thus, the information on the position of the aforementioned writing implement W and the like (electronic data) is stored in a data center and the like in the safest and most reliable method. Further, when the information on the position is stored in the server SV and the like on the aforementioned cloud, ubiquitous computing is allowed such that the

aforementioned information is immediately reproduced regardless of information devices to be used, place, time and the like. Of course, even when the information on the position of the aforementioned writing implement W and the like detected by the input device D is stored using external devices , networks and the like as described above, the storage means M mounted to (or incorporated in) the input device D may also be used as in the aforementioned embodiment illustrated in FIG. 1.

Next, a first embodiment in which a light distribution mechanism including optical waveguides forms a lattice of light beams for detection of the tip of the writing implement W within the frame 1 of an optical sensor SI will be described as a specific example of the aforementioned input device D.

FIG. 3 is a plan view illustrating a schematic configuration of an input device Dl according to the first embodiment. For ease of description in this figure, the direction of the long sides XI and X2 of the frame 1 is defined as a horizontal direction ( x-direct ion ) whereas the direction of the short sides Yl and Y2 of the frame 1 is defined as a vertical direction (y-direction) . Also, optical waveguide cores (4a, 4b, 5a and 5b) within the frame 1 are indicated by dash-and-dot lines, and light beams (invisible infrared light) in a lattice form within the frame 1 are indicated by dash-double-dot lines. The number of optical waveguide cores and the number of light beams in a lattice form are shown as abbreviated. As in FIG. 1, a battery for driving the input device D, a control means such as a driver for a light -emitting element and a light-receiving element, and a communication means (a cable or a radio antenna) for communicating with information devices such as computers, and the like are not shown (the same applies to FIGS . 4 and 5 to be described later) .

The input device Dl according to this first embodiment includes the optical sensor SI having a touch position detecting means for detecting the position (x and y coordinates) of the tip (touch position T) of the writing implement W in a rectangular region (sensing region) within the frame-shaped frame 1 by placing the optical sensor SI on a paper sheet P capable of being written upon by the writing implement W, and the storage means M for storing movement path information (change in x and y positions) on the tip position of the writing implement W obtained by this optical sensor SI.

A light-emitting optical waveguide '4 serving as a light-emitting section of the aforementioned touch position detecting means is provided in a first part of the frame 1 of the optical sensor SI. The light-emitting optical waveguide 4 has the light-emitting cores 4a on the long side XI extending in a horizontal direction, and the light-emitting cores 4b on the short side Yl extending in a vertical direction, as shown in FIG. 3. Light beams emitted from a light-emitting element (light source 2) are divided and distributed to the

light-emitting cores 4a (in a horizontal direction) and the light-emitting cores 4b (in a vertical direction) of the aforementioned light-emitting optical waveguide 4.

A light-receiving optical waveguide 5 serving as a light-receiving section of the aforementioned touch position detecting means is provided in a second part of the frame 1 opposed to the first part, with the aforementioned rectangular sensing region therebetween. The light-receiving optical waveguide 5 has the light-receiving cores 5a on the long side X2 extending in a horizontal direction, and the light-receiving cores 5b on the short side Y2 extending in a vertical direction. Light beams passing over the aforementioned sensing region and entering the light-receiving cores 5a (in a horizontal direction) and the light-receiving cores 5b (in a vertical direction) of the aforementioned light-receiving optical waveguide 5 are guided to a light-receiving element array 3 having a large number of light-receiving elements in a one-to-one

correspondence with the light-receiving cores 5a and 5b.

The aforementioned light-emitting optical waveguide 4 and the light-receiving optical waveguide 5 will be described in further detail. In the optical waveguides 4 and 5, the aforementioned cores 4a, 4b, 5a and 5b patterned into the aforementioned shape by a photolithographic method and the like are disposed between an under cladding layer and an over cladding layer (both not shown) both made of a resin material, when the optical waveguides 4 and 5 are polymer-based optical waveguides, for example.

The aforementioned light-emitting optical waveguide 4 and the light-receiving optical waveguide 5 are provided for the detection of the touch position. For this reason, the tips (light-emitting portions) of the cores 4a and 4b divided from the light-emitting optical waveguide 4 and the tips (light-receiving portions) of the cores 5a and 5b of the light-receiving optical waveguide 5 are positioned in opposed relation along the inner edges of the aforementioned frame 1, as shown in FIG. 3. Then, a lattice of light beams (dash-double-dot lines) as mentioned above is formed between the tips of the cores 4a of the light-emitting optical waveguide 4 and the tips of the cores 5a of the light-receiving optical waveguide 5 opposed to each other , with the aforementioned sensing region therebetween (in a vertical direction) and between the tips of the cores 4b of the light-emitting optical waveguide 4 and the tips of the cores 5b of the light-receiving optical waveguide 5 (in a horizontal direction) .

The polymer-based optical waveguides in which the cores 4a, 4b, 5a and 5b of the optical waveguides are made of a resin material (a polymeric material) are taken as an example in the aforementioned embodiment. The material constituting these cores, however, may be a material having a refractive index higher than that of the cladding layers provided around the cores, such as glass. It is, however, preferable that the difference in refractive index between the cores and the cladding layers provided therearound is not less than 0.01. In consideration for characteristics of patterning into the aforementioned shape, photosensitive resins such as ultraviolet curable resins are most preferably used as the material of the cores. Examples of the ultraviolet curable resins used herein include acrylic based, epoxy based, siloxane based, norbornene based, and polyimide based ultraviolet curable resins.

A material selected from among the aforementioned photosensitive resins such as ultraviolet curable resins and having a refractive index lower than that of the cores may be used for the cladding layers around the cores. Other materials usable also for a flat substrate, such as glass, silicon, metal and resin, may be used for the cladding layers. Only the under cladding layer under the cores may be provided, and the over cladding layer for covering the cores need not be formed. The aforementioned optical waveguides may be produced by a dry etching method using plasma, a transfer method, a photolithographic method using exposure and development , a photo-bleaching method, and the like. A light-emitting diode (LED) , a semiconductor laser or the like is used as the light-emitting element (light source 2) for use in the aforementioned optical sensor SI. In particular, a VCSEL (vertical cavity surface emitting laser) excellent in light transmission characteristics is preferably used as the light-emitting element (light source 2). Preferably, the wavelength of the light beams emitted from the aforementioned light source 2 is near-infrared (a wavelength of 700 to 2500 nm) .

An image sensor such as CCD and CMOS image sensors, a CMOS linear sensor array including a large number of light-receiving elements arranged in a line, and the like may be used as the light-receiving elements

(light-receiving element array 3) for use in the aforementioned optical sensor SI.

Then, as shown in FIG. 1, the optical sensor SI (storage device) including the aforementioned storage means M is removably placed on a paper sheet P so as to surround at least part of the paper sheet P. In such a case, when the tip of the writing implement W is brought down onto part of the paper sheet P revealed within the frame of the aforementioned optical sensor SI, some of the light beams passing in a lattice form within the aforementioned frame are intercepted by the tip of the writing implement W, as shown in FIG. 3. Such an intercepted location is sensed by corresponding ones of the light-receiving elements of the aforementioned touch position detecting means, whereby the coordinate positions (x and y axes; with reference to the "touch position T" in FIG. 3) of the tip of the aforementioned writing implement W within the frame are sensed and specified. The coordinates are stored in the

aforementioned storage means M. Also, when a user moves the aforementioned writing implement W to write a note or the like in that state, the path (written information such as the note or the like) of the tip of the aforementioned writing implement W in accordance with the movement is detected, and the path is stored as digital data (electronic data) in the aforementioned storage means M. That is, the information such as a note is recorded in a memory and the like in the aforementioned storage means M at the same time that the user writes the note or the like on. art of the paper sheet P revealed within the frame of the optical sensor SI with the writing implement W.

In the input device Dl according to the aforementioned first embodiment, the optical waveguides in film form or in sheet form (having a thickness, at most, of approximately 1 mm) are used for the touch position detecting means of the optical sensor SI placed within the aforementioned frame 1. Thus, the total thickness of the frame 1 is approximately 2 to 5 mm even when the thicknesses of a base, a protective plate and the like are taken into account. Therefore, the rectangular frame-shaped portion of the aforementioned optical sensor SI does not serve as an impediment to the writing operation, but makes it easyto perform the writing operation. Also, since the optical waveguides in film form or in sheet form are thin as mentioned above, the light beams emitted from the tips of the light-emitting cores 4a of the light-emitting optical waveguide 4 are allowed to travel in a vertical position slightly (approximately 0.6 mm) above the surface of the paper sheet P within the frame. Even when the aforementioned writing implement W is in a slanting position during the writing operation, the path sensed using this .lattice of light beams is deviated only slightly from the actual path of the tip of the writing implement W (the note on the paper sheet P) , and is stored in the aforementioned storage means M under proper conditions identical with those seen with the human eye.

The storage means for storing the information and the like on the position of the aforementioned writing implement W and the like is shown as mounted to the aforementioned frame 1 in the aforementioned first embodiment. However, as in the aforementioned different embodiment (FIG. 2), storage means in external devices and networks may be used as this storage means M.

Next, an input device D2 according to a second embodiment will be described in which a large number of light-emitting diodes (LEDs) serving as light-emitting elements ( a light source ) and a large number of photodiodes (PDs) serving as light-receiving elements are arranged within the frame 1 of an optical sensor S2 to thereby form a lattice of light beams for the detection of the tip of the writing implement W within the frame of the optical sensor S2.

FIG. 4 is a plan view illustrating a schematic configuration of the input device D2 according to the second embodiment. Also in this figure, the direction of the long sides XI and X2 of the frame 1 is defined as a horizontal direction ( x-direction ) whereas the direction of the short sides Yl and Y2 of the frame 1 is defined as a vertical direction ( y-direction ) . The number of LEDs and PDs and the number of light beams in a lattice form are shown as abbreviated, and electrical interconnect lines and the like within this frame are indicated by dotted lines. The aforementioned battery, the communication means and the like are not shown. The input device D2 according to this second embodiment includes the optical sensor S2 having a touch position detecting means for detecting the position (x and y coordinates) of the tip (touch position T) of the writing implement W in a rectangular region (sensing region) within the frame-shaped frame 1 by placing the optical sensor S2 on a paper sheet P capable of being written upon by the writing implement W, and a storage means M for storing movement path information (change in x and y positions) on the tip position of the writing implement W obtained by this optical sensor S2.

The input device D2 according to the aforementioned second embodiment differs from the input device Dl according to the first embodiment stated earlier in that a lattice of light beams for detecting the touch position of the tip of the writing implement W is formed by a light-emitting section including a large number of LEDs

6 serving as a light source and arranged within the frame 1 of the optical sensor S2, as shown in FIG. 4. A light-receiving section including a large number of PDs

7 corresponding to the respective LEDs 6 is provided in part (the sides X2 and Y2) of the frame 1 opposed to the part (the sides XI and Yl) of the frame 1 where the aforementioned LEDs 6 are arranged. Like the

aforementioned LEDS 6 , these PDs 7 are arranged and positioned along the inner edges of the aforementioned frame-shaped frame 1 so that the tips thereof face inward. Under the control of the. storage means MC serving also as a controller (control means) for both the LEDs 6 and the PDs 7, the aforementioned LEDs 6 are caused to emit light beams simultaneously or sequentially in a scanning direction, thereby forming a lattice of light beams (dash-double-dot lines) for the detection of the touch position in the rectangular sensing region within the frame 1.

Infrared LEDs ( infrared light-emitting diodes ) of the type which emits near-infrared light beams (at a wavelength of 700 to 2500 nm) are preferable as the LEDs 6 used as the aforementioned light-emitting elements (light source) . A linear sensor array including a large number of light-receiving elements arranged in a line in the form of a bar or an array, an image sensor, and the like in addition to the aforementioned photodiodes (PDs) may be used as the light-receiving elements.

The detection of the touch position of the writing implement W using the input device D2 according to the aforementioned second embodiment is done by the following procedure. First, the optical sensor S2 ( storage device ) including the storage means M serving also as a controller is removably placed on a paper sheet P so as to surround at least part of the paper sheet P . Next, for calibration, while the LEDs 6 of the aforementioned light-emitting section are caused to emit light beams sequentially one by one (from the end), the intensity of light beams (lattice light beams) reaching the PDs 7 corresponding to (opposed to) the LEDs 6 is measured when the light beams are emitted and when the light beams are not emitted, and threshold values for the detection and non-detection of the writing implement W based on the interception of light beams are determined for each of the PDs 7, and are stored in the form of a table and the like in the aforementioned storage means M.

Next, the storage means M serving also as the aforementioned controller causes the aforementioned LEDs 6 to sequentially emit light beams. While the sensing region of the optical sensor S2 is scanned, the tip of the writing implement W is brought down onto part of the paper sheet P revealed within the frame of this optical sensor S2. Then, as shown in FIG. 4, some of the light beams travelling in a lattice form within the

aforementioned frame are intercepted by the tip of the writing implement W. Such an intercepted location is sensed by corresponding ones of the light-receiving elements of the aforementioned touch position detecting means, whereby the coordinate positions (x and y axes; with reference to the "touch position T" in FIG. 4) of the tip of the aforementioned writing implement W within the frame are specified. The coordinates are stored in the aforementioned storage means M.

Then, when a user moves the aforementioned writing implement W to write a note or the like, the path (written information such as the note or the like) of the tip of the aforementioned writing implement W in accordance with the movement is detected, and the path is stored as digital data (electronic data) in the aforementioned storage means M. That is, the information such as a note is recorded in a memory and the like in the storage means M serving also as the aforementioned controller at the same time that the user writes the note or the like on part of the paper sheet P revealed within the frame of the optical sensor S2 with the writing implement W.

The input device D2 according to the aforementioned second embodiment may employ general-purpose components , for example the light-emitting diodes (LEDs) and the like serving as the light-emitting elements (the light source ) and the photodiodes (PDs) serving as the light-receiving elements. This allows the formation of the input device D2 at low costs.

The storage means M serving also as the controller and for storing the information and the like on the position of the aforementioned writing implement W and the like is shown as incorporated in the aforementioned frame 1 in the aforementioned second embodiment . However, as in the aforementioned different embodiment (FIG. 2) , storage means in external devices and networks may be used as this storage means M.

Next, an input device D3 according to a third embodiment will be described which includes modules disposed on two corners, respectively, of the frame 1 of an optical sensor S3 and each including a light-emitting element and a light-receiving element array, and which specifies the position of the tip of the writing implement W within a frame by a triangulation method by means of the two modules.

FIG. 5(a) is a plan view illustrating a schematic configuration of the input device D3 according to the third embodiment, and FIG. 5(b) is an enlarged view of a portion indicated by Z of FIG. 5(a) . Also in these figures, the direction of the long sides XI and X2 of the frame 1 is defined as a horizontal direction

(x-direction) whereas the direction of the short sides Yl and Y2 of the frame 1 is defined as a vertical direction (y-direction) . The aforementioned battery, the communication means and the like are not shown.

The input device D3 according to this third embodiment includes the optical sensor S3 having a touch position detecting means for detecting the position (x and y coordinates) of the tip (touch position T) of the writing implement W in a rectangular region (sensing region) within the frame-shaped frame 1 by placing the optical sensor S3 on a paper sheet P capable of being written upon by the writing implement W, and a storage means M (built-in) for storing movement path information (change in x and y positions) on the tip position of the writing implement obtained by this optical sensor S3.

The input device D3 according to the aforementioned third embodiment differs from the input devices Dl and D2 according to the first and second embodiments stated earlier in that the light-receiving and -emitting modules (camera modules CI and C2) each including a vertical combination of the light-emitting element (LED 6) and the light-receiving element array (image sensor 8) as shown in FIG. 5(b) are disposed on corners la and lb, respectively, on opposite ends of one side ( in thi s example , XI) among the four sides of the frame 1 of the optical sensor S3, and in that a tape-like ret roreflector ( retroreflective tape 9) is affixed to the inner side surface of three sides (X2, Yl and Y2 ) other than the aforementioned one side (XI) lying between these camera modules CI and C^"2 , as shown in FIG. 5(a) . The storage means M serves also as a controller (control means) for both the LEDs 6 and the image sensors 8, as in the aforementioned second embodiment.

In the optical sensor S3 in the aforementioned third embodiment having this configuration, light beams emitted from the LEDs 6 in the respective camera modules CI and C2 are reflected from the aforementioned retroreflective tape 9 to travel back toward the camera modules CI and C2 from which the light beams are emitted, so that crossing of radial light beams occurs within the frame in such a manner that the light beams from each of the camera modules CI and C2 diverge in a ripple or wave pattern, as shown in FIG. 5(a) .

Infrared LEDs ( infrared light-emitting diodes ) of the type which emits near- infrared light beams (at a wavelength of 700 to 2500 nm) are preferable as the light-emitting elements (light source) for the aforementioned camera modules CI and C2. An image sensor such as CCD and CMOS image sensors, a CMOS linear sensor array including a large number of light-receiving elements arranged in a line, and the like may be used as the light-receiving element array.

The retroreflector attached to the inner side surface of the three sides (X2, Yl and Y2) of the aforementioned frame 1 may be either of a microprism type or of a glass bead type. For ease of handling, the tape-like form is used as the retroreflector in the aforementioned example. Instead, a coating having a retroreflective property may be applied to the inner side surface of the aforementioned three sides (X2, Yl and Y2) .

The detection of the touch position of the writing implement W using the input device D3 according to the aforementioned third embodiment is done by the following procedure. First, the optical sensor S3 ( storage device ) including the storage means M serving also as a controller is removably placed on a paper sheet P so as to surround at least part of the paper sheet P . Next, for calibration, while the LEDs 6 of the aforementioned respective camera modules CI and C2 are caused to emit light beams, the intensity of light beams ( retroreflected light beams) traveling back to the image sensors 8 of the respective camera modules CI and C2 is measured when the light beams are emitted and when the light beams are not emitted, and threshold values for the detection and non-detection of the writing implement W based on the interception of light beams are determined for each of the camera modules CI and C2, and are stored in the form of a table and the like in the aforementioned storage means M.

Next, while the storage means M serving also as the aforementioned controller causes the aforementioned LEDs 6 to emit light beams, the tip of the writing implement W is brought down onto part of the paper sheet P revealed within the frame of this optical sensor S3. Then, as shown in FIG. 5(a), some of the crossing light beams travelling within the aforementioned frame are intercepted by the tip of the writing implement W. Such an intercepted location is sensed by corresponding light-receiving elements in the aforementioned camera modules CI and C2. Thus, the storage means MC serving also as the aforementioned controller performs computations using the triangulation method to specify the coordinate positions (x and y axes; with reference to the "touch position T" in FIG. 5(a)) of the tip of the aforementioned writing implement W within the frame. The storage means M stores the coordinates.

Then, when a user moves the aforementioned writing implement W to write a note or the like, the path (written information such as the note or the like) of the tip of the aforementioned writing implement W in accordance with the movement is detected and computed in a similar manner, and digital data (electronic data) on the path is stored in the aforementioned storage means M. That is, the information such as a note is recorded in a memory and the like in the storage means M serving also as the aforementioned controller at the same time that the user writes the note or the like on part of the paper sheet P revealed within the frame of the optical sensor S3 with the writing implement W.

The input device D3 according to the aforementioned third embodiment may employ general-purpose components, for example the light-emitting diodes (LEDs) and the like serving as the light-emitting elements (the light source) and the image sensors such as CCD and CMOS image sensors serving as the light-receiving elements. Combined with a small number of optical components constituting the input device D3, this allows the formation of the input device D3 at low costs.

The storage means M serving also as the controller and for storing the information and the like on the position of the aforementioned writing implement W and the like is shown as incorporated in the aforementioned frame 1 in the aforementioned third embodiment . However, as in the aforementioned different embodiment (FIG. 2), storage means in external devices and networks may be used as this storage means M.

Examples

Next, an example of a method of producing the input device Dl (the first embodiment including the optical waveguides 4 and 5) described in the aforementioned embodiment will be described. It should be noted that the present invention is not limited to the inventive examples to be described below.

First, a method of manufacturing the optical waveguides 4 and 5 for use in the aforementioned input device Dl will be described.

FIGS. 6(a) to (f) are views illustrating the method of manufacturing the optical waveguides 4 and 5 for use in the input device Dl according to this example.

In this example, the light-emitting optical waveguide 4 having the cores 4a (on the long side XI) and the cores 4b (on the short side Yl) for light emission, and the light-receiving optical waveguide 5 having the cores 5a (on the long side X2 ) and the cores 5b (on the short side Y2) for light reception are formed integrally with each other in the shape of a frame (with reference to FIG. 3) .

(Preparation of Substrate)

First, a substrate 10 in the form of a rectangular frame for the formation of the optical waveguides 4 and 5 is prepared. Examples of a material for the formation of this substrate 10 include metal, resin, glass, quartz, and silicon.

(Production of Under Cladding Layer) Then, as shown in FIG. 6(a), a rectangular frame-shaped under cladding layer 11 identical in shape with the substrate 10 is formed on a surface of the aforementioned rectangular frame-shaped substrate 10. This under cladding layer 11 may be formed by a photolithographic method using a photosensitive resin as a material for the formation thereof. The under cladding layer 11 has a thickness in the range of 5 to 50 μηα, for example.

(Production of Cores)

Next, as shown in FIG. 6(b), the light-emitting cores 4a and 4b (not shown) and the light-receiving cores 5a and 5b (not shown) which have the aforementioned pattern are formed by a photolithographic method on a surface of the aforementioned rectangular frame-shaped under cladding layer 11. It should be noted that only a core 4a and some cores 5a are typically shown in FIG. 5(b) . An example of a material for the formation of the cores 4a, 4b, 5a and 5b used herein includes a photosensitive resin having a refractive index higher than that of the materials for the formation of the aforementioned under cladding layer 11 and an over cladding layer 12 to be described below (with reference to FIG. 6(e) ) .

(Production of Over Cladding Layer)

Then, a rectangular frame-shaped light-transmissive mold 20 for the formation of the over cladding layer as shown in FIG. 6(c) is prepared. This mold 20 includes a cavity 20a having a mold surface complementary in shape to the surface of the over cladding layer 12 (with reference to FIG. 6(e) ) . The mold 20 is placed on a molding stage (not shown), with the cavity 20a positioned to face upward. Then, the cavity 20a is filled with a photosensitive resin (varnish) 12' serving as the material for the formation of the over cladding layer 12.

Then, as shown in FIG. 6(d), the cores 4a and 5a (4b and 5b) patterned on the surface of the aforementioned under cladding layer 11 are positioned relative to the cavity 20a of the aforementioned mold 20. In that state, the aforementioned under cladding layer 11 is pressed against the aforementioned mold 20, so that the aforementioned cores 4a and 5a are immersed in the photosensitive resin 12' serving as the material for the formation of the aforementioned over cladding layer 12. In this state, the aforementioned photosensitive resin 12' is exposed to irradiation light such as ultraviolet light by directing the irradiation light through the aforementioned mold 20 onto the aforementioned photosensitive resin 12'. Thus, the aforementioned photosensitive resin 12 ' is cured to form the rectangular frame-shaped over cladding layer 12 having a rectangular frame-shaped inner peripheral edge portion formed as a lens portion 12.

(Removal of Optical Waveguides from Mold) Next, as shown in FIG . 6(e) ( shown in an orientation vertically inverted from that shown in FIG. 6(d)), the over cladding layer 12 together with the aforementioned substrate 10, the under cladding layer 11, and the cores 4a and 5a (4b and 5b) is removed from the aforementioned mold 20. Then, as shown in FIG. 6(f), the a forement ioned substrate 10 is stripped from the under cladding layer 11. This provides the rectangular frame-shaped optical waveguides 4 and 5 integral with each other and including the under cladding layer 11, the cores 4a, 4b, 5a and 5b, and the over cladding layer 12.

For the purpose of improving the light transmission efficiency of the optical waveguides according to the aforementioned example, the tips of the light-emitting cores 4a and 4b and the tips of the light-receiving cores 5a and 5b are formed as lens portions, and the edge portion of the over cladding layer 12 covering the lens portions of the cores 4 a , 4b, 5a and 5b is formed as the lens port ion . However, when the light (space) transmission efficiency within the frame of the optical sensor SI is sufficient, the aforementioned lens portion (s) may be formed in only either the light-emitting cores 4a and 4b or the light-receiving cores 5a and 5b, or be formed in neither the light-emitting cores 4a and 4b nor the light-receiving cores 5a and 5b. Also, the light-emitting optical waveguide 4 and the light-receiving optical waveguide 5 are produced integrally with each other in the aforementioned example. However, these optical waveguides 4 and 5 may be produced separately or be formed by combining a larger number of optical waveguide parts together.

Next, the optical sensor SI is produced using the aforementioned rectangular frame-shaped and integral optical waveguides 4 and 5.

(Production of Optical Sensor)

First, a rectangular frame-shaped retainer plate serving as a base (frame) of the optical sensor SI is prepared. The sides of the rectangular frame of this retainer plate are made slightly wider than those of the aforementioned rectangular frame-shaped optical waveguides 4 and 5. Examples of a material for the formation of this retainer plate include metal, resin, glass, quartz and silicon. In particular, stainless steel is preferable in having a good ability to hold the planarity thereof. The retainer plate has a thickness of approximately 0.5 mm, for example. Next, the aforementioned rectangular

frame-shaped optical waveguides 4 and 5 are affixed to a predetermined position of a surface of the

aforementioned retainer plate. As shown in FIG. 3, a VCSEL (vertical cavity surface emitting laser) serving as the light source 2 is aligned and mounted to a light-receiving end portion of the aforementioned light-emitting optical waveguide 4, and the

light-receiving element array 3 is aligned and mounted to a light-emitting end portion of the aforementioned light-receiving optical waveguide 5 so that the optical axes of the light-receiving elements coincide with the corresponding cores 5a and 5b.

Then, the top surface of the optical waveguides except the lens portion of the aforementioned over cladding layer 12 is covered with a protective plate and the like. This provides the frame-shaped optical sensor SI as shown in FIG. 3. Examples of a material for the formation of the aforementioned protective plate include resin, metal, glass, quartz, and silicon. Preferably, the protective plate has a thickness of approximately 0.5mm, forexample. When communication with information devices is performed by radio, it is desirable that the aforementioned protective plate 40 is made of resin such as polycarbonate which allows radio waves to pass therethrough.

The storage means M for storing the movement path information on the tip position of the writing implement W as mentioned earlier is mounted to an outer periphery of the aforementioned frame-shaped optical sensor SI. This storage means M may be of a removable type such as a USB memory device.

Also, devices not shown in FIG. 3 described above, for example a battery for driving this input device Dl, a control means such as a driver IC, and a communication means (a cable connection port or a radio antenna) for communication with and connection to information devices , are connected to the aforementioned frame-shaped optical sensor SI. It is desirable that these devices used herein are thin devices ( film-like parts , electrical components of micro type and the like) which can be inserted into space between the retainer plate and the protective plate constituting the aforementioned frame 1. This allows the frame to be made so. thin (approximately 2 to 3 mm in total thickness) as not to serve as an impediment to a writing operation with a writing implement.

Next, details on the input device produced based on the aforementioned example will be described.

Component A: 75 parts by weight of an epoxy resin containing an alicyclic skeleton (EHPE 3150 manufactured by Daicel Chemical Industries, Ltd.)

Component B: 25 parts by weight of an

epoxy-group-containing acrylic polymer (MARPROOF

G-0150M manufactured by NOF Corporation)

Component C: four parts by weight of a photo-acid generator (CPI-200K manufactured by San-Apro Ltd.)

A material for the formation of an under cladding layer was prepared by dissolving these components A to

C together with five parts by weight of an ultraviolet absorber (TINUVIN 479 manufactured by Ciba Japan K.K.) in cyclohexanone (a solvent).

<Material for Formation of Cores of Optical

Waveguide>

Component D: 85 parts by weight of an epoxy resin containing a bisphenol A skeleton (157S70 manufactured by Japan Epoxy Resins Co., Ltd.)

Component E: five parts by weight of an epoxy resin containing a bisphenol A skeleton (EPIKOTE 828 manufactured by Japan Epoxy Resins Co., Ltd.)

Component F: 10 parts by weight of an

epoxy-group-containing styrenic polymer (MARPROOF G-0250SP manufactured by NOF Corporation) A material for the formation of cores was prepared by dissolving these components D to F and four parts by weight of the aforementioned component C in ethyl lactate.

Component G: 100 parts by weight of an epoxy resin having an alicyclic skeleton (EP4080E manufactured by ADEKA Corporation)

A material for the formation of an over cladding layer was prepared by mixing this component G and two parts by weight of the aforementioned component C together .

The material for the formation of the

aforementioned under cladding layer (varnish) was applied to a surface of a rectangular frame-shaped substrate made of stainless steel (having a thickness of 50 μπι) .

Thereafter, a heating treatment was performed at 160°C for two minutes to form a photosensitive resin layer. Then, the aforementioned photosensitive resin layer was exposed to irradiation with ultraviolet light at an integrated dose of 1000 mJ/cm². Thus, the rectangular frame-shaped under cladding layer having a thickness of 10 μπι (with a refractive index of 1.510 at a wavelength of 830 nm) was formed. Then, the material for the formation of the aforementioned cores was applied to a surface of the aforementioned rectangular frame-shaped under cladding layer. Thereafter, a heating treatment was performed at 170°C for three minutes to form a photosensitive resin layer. Next, exposure was performed at an integrated dose of 3000 mJ/cm² by the irradiation with ultraviolet light through a photomask (with a gap of 100 μκι) .

Subsequently, a heating treatment was performed at 120°C for 10 minutes. Thereafter, development was performed using a developing solution ( γ-butyrolactone ) todissolve away unexposed portions. Thereafter, a drying process was performed at 120°C for five minutes. Thus, the cores having a width of 30 μπι and a height of 50 μπι (with a refractive index of 1.570 at a wavelength of 830 nm) were patterned .

Next, a rectangular frame-shaped

light-transmissive mold for the formation of the over cladding layer was prepared. This mold includes a cavity having a mold surface complementary in shape to the surface of the over cladding layer (with reference to FIG. 6(c) ) . The mold was placed on a molding stage, with the cavity positioned to face upward. Then, the cavity was filled with the material for the formation of the aforementioned over cladding layer. Then, the cores patterned on the surface of the aforementioned under cladding layer were positioned relative to the cavity of the aforementioned mold. In that state, the aforementioned under cladding layer was pressed against the aforementioned mold, so that the aforementioned cores were immersed in the material for the formation of the aforementioned over cladding layer. In this state, exposure was performed at an integrated dose of 8000 mJ/cm² by irradiating the material for the formation of the aforementioned over cladding layer with ultraviolet light through the aforementioned mold . Thus, the rectangular frame-shaped over cladding layer having a rectangular frame-shaped inner peripheral edge portion formed as a convex lens portion was formed. The convex lens portion had a substantially quadrantal curved lens surface (having a radius of curvature of 1.4 mm) as seen in sectional side view.

Next, the aforementioned over cladding layer together with the aforementioned substrate, the under cladding layer and the cores was removed from the aforementioned mold. Then, the aforementioned

substrate was stripped from the under cladding layer. This provided a rectangular frame-shaped optical waveguide (having a total thickness of 1 mm) including the under cladding layer, the cores, and the over cladding layer (with reference to FIG. 3) .

Next, a rectangular frame-shaped retainer plate made of stainless steel (having a thickness of 0.5 mm) was prepared which had three sides slightly wider than those of the aforementioned optical waveguide and a remaining one side enough wider than the three sides. The aforementioned rectangular frame-shaped optical waveguide was affixed to a predetermined position of a surface of this retainer plate, and a film-like polymer battery and thin electrical components such as a film antenna were fixed on an outside edge of the widest side of the aforementioned retainer plate. Then, a light-emitting element (SM85-2N001 manufactured by Optowell Co., Ltd.) and a light-receiving element

(S-10226 manufactured by Hamamatsu Photonics K.K. ) were aligned, positioned, and fixed. Components for placement on an outer rim of the retainer plate, such as a connection port to a USB memory device and a connection port to an AC adapter, were mounted.

Thereafter, a protective plate made of polycarbonate (having a thickness of 0.5 mm) for protecting the optical waveguide, the electrical components and the like was mounted onto the

aforementioned retainer plate. Thus, an optical sensor was provided. Part of this optical sensor corresponding to the optical waveguide, together with the retainer plate and the protective plate on the front and back surfaces thereof, had a total thickness of 2 mm. Part of the optical sensor where the aforementioned remaining electrical components were fixed, together with the retainer plate and the protective plate on the front and back surfaces thereof, had a total thickness of 3 mm.

<0peration Check of Input Device>

A memory serving as a storage means was attached to a memory connection port of the aforementioned optical sensor, and this input device was placed on a paper sheet. A note was written on part of the paper sheet revealed within the frame with a writing implement. Then, the aforementioned input device and a notebook-si zed personal computer were connected to each other via wireless communication (BLUETOOTH®) so that communication was established therebetween. Information stored in the memory of the aforementioned input device was reproduced using the notebook-sized personal computer. The result was that a note identical with that written on the aforementioned paper sheet appeared on a display of the aforementioned notebook-sized personal computer. Using the aforementioned notebook-sized personal computer, information ( electronic informat ion ) on a note was stored in the memory of the aforementioned notebook-sized personal computer at the same time that the note was written on the aforementioned paper sheet. Then, a note identical with that written on the aforementioned paper sheet appeared immediately in a similar manner on the display, of the notebook-sized personal computer.

Although a specific form of embodiment of the instant invention has been described above and illustrated in the accompanying drawings in order to be more clearly understood, the above description is made by way of example and not as a limitation to the scope of the instant invention. It is contemplated that various modifications apparent to one of ordinary skill in the art could be made without departing from the scope of the invention which is to be determined by the following claims .

The input device according to the present invention is capable converting information such as a note into electronic form at the same time that the information such as a note is written on a paper sheet revealed within the frame.

Claims

1. An input device comprising:

a frame-shaped optical sensor capable of surrounding at least part of a paper sheet capable of being written upon by a writing implement, the optical sensor including a rectangular frame, and at least one pair of light-emitting and light-receiving elements mounted to the rectangular frame, the optical sensor sensing the interception of light beams traveling from the light-emitting element to the light-receiving element which is caused by a tip of the writing implement within the frame to thereby output information on the position of the writing implement within the frame; and

a storage means for storing therein the movement path of the tip of the writing implement as electronic data when a writing operation is performed on part of the paper sheet revealed within the frame of the optical sensor with the writing implement.

2. The input device according to claim 1, wherein the rectangular frame of the frame-shaped optical sensor including first and second sections opposed to each other in the form of the rectangular frame includes an optical waveguide including a plurality of light-emitting cores and a plurality of light-receiving cores, the light-emitting cores being formed in the first section, the light-receiving cores being formed in the second section, the cores having respective tips positioned on inner edges of the rectangular frame so that the tips of the light-emitting cores and the tips of the light-receiving cores are opposed to each other, and

wherein light beams emitted from the

light-emitting cores of the optical waveguide toward the light-receiving cores thereof produce a lattice of vertical and horizontal light beams crossing each other within the frame.

3. The input device according to claim 1, wherein the rectangular frame of the frame-shaped optical sensor includes first and second sections opposed to each other in the form of the frame;

wherein light-emitting elements are arranged in the first section and light-receiving elements are arranged in the second section;

wherein the light-emitting elements and the light-receiving elements are positioned to face an interior of the rectangular frame; and

wherein light beams emitted from the

light-emitting elements toward the light-receiving elements produce a lattice of vertical and horizontal light beams crossing each other within the rectangular frame .

4. The input device according to claim 1, wherein modules , each including a light-receiving element array composed of a plurality of the

light-receiving elements and the light-emitting element in vertically stacked relation are disposed on two corners, respectively, on opposite ends of one side among the four sides of the frame of the frame-shaped optical sensor;

wherein a tape-like retroreflector is provided on the inner side surface of three sides other than the one side lying between the modules; and

wherein light beams emitted from the

light -emitting element of one of the modules are reflected from the retroreflector to travel back into the light-receiving element array of the one module.

5. The input device according to any one of claims 1 to 4, wherein the optical sensor and the storage means are formed integrally as a storage device, and the storage device is placeable on or removable from the paper sheet.