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Publication numberUS3911215 A
Publication typeGrant
Publication dateOct 7, 1975
Filing dateMar 18, 1974
Priority dateMar 18, 1974
Publication numberUS 3911215 A, US 3911215A, US-A-3911215, US3911215 A, US3911215A
InventorsColwell Jr William C, Hurst George S
Original AssigneeElographics Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Discriminating contact sensor
US 3911215 A
Abstract
A sensor construction is described for normally maintaining two juxtaposed electrical potential carrying sheets, at least one being flexible, separated from each other but permitting contact therebetween when an object of specified radius of curvature is pressed against the flexible sheet. The separation of the sheets is accomplished by producing discrete small buttons of insulation, preferably on the flexible sheet, with the spacing and the height of the buttons determining the largest radius of curvature to which the sensor will respond. This construction is specifically applied to a telescriber sensor or the like whereby contact is made only by depression of the flexible sheet with a writing instrument and not by any portion of a writer's hand.
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Description  (OCR text may contain errors)

United States Patent Hurst et al.

DISCRIMINATING CONTACT SENSOR lnventors: George S. Hurst; William C.

Colwell, Jr., both of Oak Ridge, Tenn.

Assignee: Elographics, Inc., Oak Ridge, Tenn.

Filed: Mar. 18, 1974 Appl. No.: 452,784

US. Cl. 178/18; 200/86 R lnt. Cl. H01H 43/08; H04N 1/00 Field of Search 200/86 R, 153 M, 46, 159;

[56] References Cited UNITED STATES PATENTS 3,617,666 11/1971 Braue 200/86 R 3,632,874 1/1972 Malavard et al.. 3,668,337 6/1972 Sinclair 200/86 R 3,722,086 3/1973 Wikkerink et al. 200/86 R Primary ExaminerThomas A. Robinson Attorney, Agent, or FirmMartin J. Skinner 5 7 ABSTRACT A sensor construction is described for normally maintaining two juxtaposed electrical potential carrying sheets, at least one being flexible, separated from each other but permitting contact therebetween when an object of specified radius of curvature is pressed against the flexible sheet. The separation of the sheets is accomplished by producing discrete small buttons of insulation, preferably on the flexible sheet, with the spacing and the height of the buttons determining the largest radius of curvature to which the sensor will respond. This construction is specifically applied to a telescriber sensor or the like whereby contact is made only by depression of the flexible sheet with a writing instrument and not by any portion of a writers hand.

6 Claims, 5 Drawing Figures US. Patent 0a. 7,1975

VOLTAGE SOURCE SAMPLE AND HOLD X-ANALOG Sheet 1 0m 3,911,215

VOLTAGE 19 7 SOURCE OSCILLATOR SAMPLE AND HOLD Y-ANALOG F|G.1

(Prior Arr) US. Patent 0a. 7,1975 Sheet 2 of2 3,911,215

FIG.

m x m m x x m FlG.4

DISCRINHNATING CONTACT SENSOR BACKGROUND OF THE INVENTION Our invention relates generally to the insulation of one electrical potential carrying sheet from a second such sheet except when contact therebetween is purposely desired, and more specifically to insulation means whereby the sheets are brought into contact only by an object having a radius of curvature less than a specific value, the value being established by the arrangement of the insulation. The invention is illustrated as applied to writing sensors useful for the electrographic determination of coordinates of a point or for the telemetry of drawings, signatures and the like.

Typical of the prior art in this field is found in US. Pat. No. 3,632,874 issued to L. C. Malavard et al. In that patent, and specifically FIG. 9, a conductive sheet of flexible material is separated only by an air space from a second surface or sheet to which is applied orthogonal electrical fields. A writing instrument is used to bring the sheets together and thereby generate xand y-related signals as the writing instrument is moved. However, it may be seen that finger tips, knuckles, the edge of the hand, or other objects could deform the flexible sheet and give rise to erroneous output signals.

In copending application Ser. No. 244,629, now US. Pat. No. 3,798,370, issued to G. S. Hurst on Mar. 19, 1974, a sensor is described in which a deformable insulation is utilized between a flexible conductive grounding sheet and a resistive sheet having the orthogonal electric fields. In one embodiment a gel separates the layers. Although the gel provides the necessary insulation between the sheets, it is not a practical solution for production units because of the care required to produce a reproducible characteristic. A second embodiment, in the form of a nylon net or the like, is amenable to the production of sensors and is satisfactory for many applications of the sensor. However, when handwriting is performed on the sensors fabricated using the net, the nonuniform thickness (the threads versus the knots) of even the finest available net material may be felt during the writing. Also, movement of the net between the layers gives rise to gradual deterioration of the materials in contact therewith.

SUMMARY OF THE INVENTION Our invention in its simplest form utilizes a distribution of small discrete insulating buttons of uniform height to normally separate two electrical potential carrying sheets where at least one of the sheets is flexible. The buttons may be either uniformly or randomly distributed and are preferably affixed to the flexible sheet. The spacing and height of the insulating buttons are chosen, assuming a fixed diameter, so as to prevent contact of the layers by an object having a radius of curvature greater than a selected value and thereby discriminate between objects of different radii of curvature. Specifically, the dimensions are chosen to permit contact between the layers upon deformation by a conventlonal writing instrument but prevent contact by anv part of a hand holding the writing instrument. In this structure we eliminate any physical or psychological deterrents to normal handwriting.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a simplified circuit, substantially as found in above-referenced copending application (now US. Pat. No. 3,798,370), for the purpose of permitting a description herein of one application of our invention;

FIG. 2 is an enlarged cross sectional drawing illustrating the most general form of the subject matter of our invention;

FIG. 3 is an enlarged cross sectional view of our invention when contacted by an object of less than a specified radius of curvature for a given set of parameters for the insulation;

FIG. 4 is an enlarged cross sectional view of our invention when contacted by an object of greater than a specified radius of curvature; and

FIG. 5 is an enlarged cross section drawing of an electrographic sensor embodying our invention for point coordinate determination, written telemetry and the like.

DETAILED DESCRIPTION The underlying principle of our invention may be explained through the use of FIG. 2 which shows the essential components of the sensor in an enlarged cross sectional view. Two substantially planar and parallel sheets 23, 24 are assumed to have an electrical potential applied thereto by any conventional means such as described hereinafter. Sheet 23 is flexible, so as to be deformable toward the second sheet 24 which may be rigid. Typical of the flexible material is Velostat, a conductive plastic distributed by Customs Materials, Inc., of Chelmsford, Mass, or Mylar (E. I. DuPont) with an aluminized surface as manufactured by numerous companies. The second sheet may be a conductive metal plate or, alternatively, a resistive paper supported on an appropriate backing. If a resistive sheet is utilized, a typical material is resistance paper Type L, manufactured by Knowlton Bros, Watertown, N. Y., having a resistance of 1000 to 2000 ohms per square.

Separating the sheets 23 and 24 are a plurality of distributed insulation buttons 25 preferably attached, as shown, to the flexible sheet for most applications. These buttons are of substantially equal diameter, D, and height, H, and may be randomly or uniformly distributed with a spacing, S, being either an average spacing (if random) or the actual center-to-center spacing (if uniform). The diameter, D, is very much smaller than the spacing, S. In general, a small diameter is desirable, and the height and spacing are chosen for a particular application of the layered structure. The insulating buttons 25 may be applied to sheet 23 using one of several standard techniques again depending upon the dimensions. Typical application methods are air-jet spraying, electrostatic spraying, rollers and silk screen techniques. The material utilized to form the buttons may be, for example, insulating printers ink, epoxy paint or varnish.

With the construction shown in FIG. 2, we have determined that the height and spacing (with a small fixed diameter) will affect the manner of deforming sheet 23 so as to contact sheet 24. We have developed a quantitative relationship for the condition that the two sheets can be brought into contact by pressing the flexible sheet with an object. This relationship can be expressed in terms of the radius of curvature, R, of the pressing 3 object using the equation R S /SH. An object having a radius of curvature smaller than the value of S /8H will bring about contact of the layers, as shown in FIG. 3. In contrast, an object of radius of curvature greater than S /SH will not bring about contact, as illustrated in FIG. 4.

This characteristic of discrimination by the structure as to the radius of curvature may be used, for example, to determine the number of particles of a given size range that impinge against the flexible layer 23. Thus, the structure would be used as a switch in a conventional electrical counting system. The use of several sensors each having a discrimination corresponding to different values of R would provide an electrical counting system capable of counting the number of impinging particles having various radii of curvature.

Our invention, however, is of particular value in telemetry sensors and coordinate determining sensors. Typical of such sensors is that described in the aforementioned copending patent application of G. S. Hurst. This may be understood by referring to FIG. 1 which is a schematic circuit diagram of that patent application, and to FIG. which is an enlarged cross section of a sensor embodying our present invention for use with the circuit of FIG. 1. Referring first to FIG. 1, a uniform highly resistive sheet 10 is suitably mounted by any conventional means to a support (not shown) so as to form a plane. In each comer of sheet 10 are spot electrodes 11 as at points A, B, C, and D. Spacedbetween the corner spot electrodes, in a row-like manner, are edge spot electrodes 12 along each edge of sheet 10. Three edge electrodes are shown along each edge for illustration; an actual sensor may have more or less for a particular size and application.

Connected between adjacent spopt electrodes 11 and 12 are individual discrete high precision (e.g., 0.1 to 1.0%) resistors 13. These resistors 13, in series along each edge, form four resistor networks joined to electrodes 11 at points A, B, C and D. It will be recognized that this structure, using discrete resistors, permits the choice of preferred precision resistive elements to assist in the establishment of uniform electrical gradients in the resistive paper 10.

The ends of each resistor network are connected, in an appropriate sequence, to a voltage source 18 or 19 by appropriate switches such as 14a, 14b, etc., in order to achieve orthogonal electric fields. Although a single switch across each network would function in the same manner, solid state switches required for rapid operation (e.g., 10 -10 Hz) often exhibit ohmic resistance in the closed position. However, the resistance of each of the contacts of a chip of four switches is substantially equal and thus the circuit as shown overcomes the effect of differing internal resistance. Operation of the switches l4l7 is governed by the output signals of oscillator 20.

Further details of the electrical circuit may be found in the cited copending application (now US. Pat. No. 3,798,370). The operation of the circuit results in uniform orthogonal electric fields being generated in resistive sheet 10 during mutually exclusive time periods. Accordingly, when any specific electrical potential (such as an electrical ground) is applied at a point on the resistive sheet, as by bringing sheet 23 into contact with sheet 10, output signals are produced that are related to the xand y-coordinates of the point. The coordinates are sampled at the rate of the oscillator; thus,

the coordinates of a moving point may be followed from the signals generated at the output of conventional sample-and-hold circuits 21, 22. These sampleand-hold circuits maintain the signal due to one coordinate while the other coordinate signal is being measured and then update the signal with new values.

In practice, the resistive sheet 10 is made a portion of a sensor unit such as illustrated in FIG. 5. This shows the sheet 10 and an electrode 12 mounted within a case 26. Spaced above resistive sheet 10, and parallel thereto, is the flexible conductive sheet 23 such as formed from aluminzed Mylar or the like. The flexible layer 23 is normally separated by the insulator buttons 25 from the resistive sheet 10 as described hereinabove. Placed upon the flexible sheet 23 is a protective cover sheet 27. Any conventional writing instrument 28, such as a ball-point pen or pencil, may be moved over the surface of the cover sheet 27, or another sheet (not shown) laid thereon, so as to depress the flexible sheet 23 to bring about contact with the resistive sheet 10 thus initiating electrical signals corresponding to the coordinates of the contact point.

In order that the writing instrument 28, if moved continuously on the sheet 27, will not be above an insulating button25 more than about 1% of the time, a maximum button size (diameter) of less than 0.005 in. (0.125 mm) is preferred. With this condition, the time of interruption of electrical contact between sheets 10 and 23 during continuous writing will be much less than 1%. The spacing between buttons 25 should be much greater than the diameter of the buttons and for this application may be in a range of about 0.025 to 0.075 in. (0.635 1.9 mm). The height of the buttons, if less than about 0.005 in. (0.125 mm) cannot be felt as writing occurs. In order to provide reasonable discrimination between pressure of a writing instrument and portions of a writers hand, the above-cited equation, R z 5 8H, may be used to determine the value of R for various values of separation, S, and height, H. For example, if S 0.030 in. (0.66 mm) and H 0.001 in. (0.025 mm) then R equals about 0.1 in. (2.54 mm). With S 0.050 and H= 0.002 in. (1.27 and 0.05 mm, respectively), R becomes 0.15 in. (3.8 mm). Either of these values are sufficiently small such that the portions of a writers hand will not cause contact between the flexible sheet 23 and the resistive sheet 10. However, an instrument like a ball-point pen with a radius of curvature of about 0.025 in. (0.635 mm) will readily cause contact as it moves across the surface except when over a button 1% or less of the surface). Accordingly, continuous writing may be performed with output signals being derived continuously that are proportional to the writing instrument position.

The output signals of the circuit may be utilized in many ways. For example, if the sensor is utilized for signature verification, the signals may be transmitted to a remote stationwhere a duplicate of the signature may be produced using conventional equipment (e.g., an oscilloscope). Alternatively, the signals may be compared with signals held in storage in a computer for verification of the identity.

In another utilization, data points on graphs and the like may be digitized, displayed, reproduced and/or stored. This would apply also to storage of information related to sketches of proposed design of an apparatus part, etc., until a final design is completed. Furthermore, output signals derived from data may be processed by a programmed calculator to compute desired information.

Having described several applications for our invention, it will become apparent to those versed in the art that the basic sensor has many applications. We mean, by the term basic sensor, a composite of a pair of sheets, each being capable of carrying an electrical potential and at least one being flexible, separated by small discrete buttons of insulating medium. The preferred dimensions of the insulating buttons will vary according to the utilization of our discriminating sensor. For most applications, one of the layers will be a resistive sheet in which may be established orthogonal electric fields. Although we prefer applying the present invention to the sensor of the cited copending application (now U.S. Pat. No. 3,798,370), it may be applied to sensors such as those described in US. Pat. Nos. 3,632,874, 3,449,516, 3,670,103, etc.

1 claim:

1. A discriminating contact sensor which will respond only toa contacting object having a radius of curvature less than a specific value, which comprises: a first sheet of a flexible material capable of being energized to establish an electrical potential thereon, a second sheet capable of being energized to establish an electrical potential thereon in juxtaposition with the first sheet, and a plurality of substantially uniform discrete insulating buttons electrically separating the first and second sheets throughout the sensor, the buttons having a height and an average spacing whereby the maximum radius of curvature of the object to which the sensor will respond is approximately equal to the square of the average spacing between the buttons divided by eight times the height of the buttons.

2. The sensor of claim 1 wherein the insulating buttons are substantially circular in a section parallel to the first and second sheets and have a diameter from about 0.001 to about 0.015 in., an average spacing between adjacent buttons of from about 0.025 to about 0.075 in. and a height in a direction perpendicular to the first and second sheets of from about 0.0005 to about 0.015 in.

3. An improved electrographic sensor for writing thereon of the type wherein a uniform resistive sheet having electrodes attached thereto for the application of orthogonal electrical potentials is overlaid with a flexible conductive sheet and spaced therefrom so as to normally prevent contact therebetween but permit contact when the flexible sheet is deformed by an object having a radius of curvature less than a specific value, wherein the improvement comprises: discrete insulator buttons of substantially uniform size electrically separating the sheets throughout the sens0r, the buttons having a height and an average spacing whereby the maximum radius of curvature of the object to which the sensor will respond is approximately equal to the square of the average spacing between the buttons divided by eight times the height of the buttons.

4. The sensor of claim 3 wherein the insulating buttons are attached to the surface of the conductive sheet.

5. The sensor of claim 3 wherein the buttons have a diameter from about 0.001 to about 0.015 in., the height thereof is from about 0.0005 to about 0.015 in., and the average spacing between the buttons is from about 0.025 to about 0.075 in.

6. The sensor of claim 3 wherein the electrodes attached to the resistive sheet are a plurality of spot electrodes equally spaced along each edge of the resistive sheet; and further comprising a plurality of discrete resistors each of which are connected between adjacent of the spot electrodes whereby a series resistor network is formed along each edge of the resistive sheet.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3617666 *Apr 30, 1970Nov 2, 1971Data Appliance CorpPressure-operated layered electrical switch and switch array
US3632874 *Dec 29, 1969Jan 4, 1972AnvarGraphic data transcription system
US3668337 *Jan 18, 1971Jun 6, 1972Thomas & Betts CorpMatrix switch with improved flexible insulative spacer arrangement
US3722086 *Aug 21, 1970Mar 27, 1973Lanson Ind IncProcess for making floor mat switches
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4035768 *May 3, 1976Jul 12, 1977Veripen, Inc.Personal identification apparatus
US4220815 *Dec 4, 1978Sep 2, 1980Elographics, Inc.Nonplanar transparent electrographic sensor
US4442317 *Sep 14, 1981Apr 10, 1984Sun-Flex Company, Inc.Coordinate sensing device
US4444998 *Oct 27, 1981Apr 24, 1984Spectra-Symbol CorporationTouch controlled membrane for multi axis voltage selection
US4456787 *Jul 6, 1982Jun 26, 1984Scriptel CorporationElectrographic system and method
US4463232 *Jun 10, 1982Jul 31, 1984Toho- Polymer Kabushiki KaishaMembrane switch having spacer posts
US4484026 *Mar 15, 1983Nov 20, 1984Koala Technologies CorporationTouch tablet data device
US4493104 *Dec 11, 1981Jan 8, 1985Moore Business Forms, Inc.Character recognition device
US4523654 *Sep 14, 1983Jun 18, 1985Scriptel CorporationElectrographic system
US4529959 *Jan 31, 1984Jul 16, 1985Alps Electric Co., Ltd.Input device
US4550250 *Nov 14, 1983Oct 29, 1985Hei, Inc.Cordless digital graphics input device
US4581483 *Mar 30, 1984Apr 8, 1986Koala Technologies CorporationInterface circuitry for interconnecting touch tablet with a computer interface
US4600807 *Oct 26, 1984Jul 15, 1986Scriptel CorporationElectrographic apparatus
US4620062 *Oct 10, 1984Oct 28, 1986Rdi Limited PartnershipDevice for forming signals which are characteristic of the position of a point determined on a surface
US4631355 *Dec 18, 1984Dec 23, 1986At&T Bell LaboratoriesTelautograph system
US4636582 *Aug 29, 1984Jan 13, 1987Toppan Moore Co., Ltd.Signal input sheet having a conductive shield layer
US4650926 *Jun 7, 1985Mar 17, 1987Scriptel CorporationElectrographic system and method
US4677417 *Dec 6, 1985Jun 30, 1987Alps Electric Co., Ltd.Tablet type input device
US4678869 *May 27, 1986Jul 7, 1987Scriptel CorporationPosition responsive apparatus, system and method having electrographic application
US4707570 *Feb 12, 1986Nov 17, 1987Ricoh Company, Ltd.Manual information input device
US4801767 *Jun 1, 1987Jan 31, 1989Omron Tateisi Electronics Co.Coordinate inputting sheet with auxiliary electrodes promoting accuracy of positional detection
US4801771 *Oct 13, 1987Jan 31, 1989Yamaha CorporationForce sensitive device
US4806709 *May 26, 1987Feb 21, 1989Microtouch Systems, Inc.Method of and apparatus for sensing the location, such as coordinates, of designated points on an electrically sensitive touch-screen surface
US4821029 *Apr 26, 1984Apr 11, 1989Microtouch Systems, Inc.Touch screen computer-operated video display process and apparatus
US4897511 *Jun 16, 1988Jan 30, 1990Gunze LimitedMethod of detection of the contacting position in touch panel sensor
US4914624 *May 6, 1988Apr 3, 1990Dunthorn David IVirtual button for touch screen
US4958148 *Jan 22, 1988Sep 18, 1990Elmwood Sensors, Inc.Contrast enhancing transparent touch panel device
US4963417 *Jul 1, 1988Oct 16, 1990Toray Industries, Inc.Electroconductive substrate containing deformable dielectric resin particles covered by conductive film
US4990900 *Jun 9, 1988Feb 5, 1991Alps Electric Co., Ltd.Touch panel
US5087825 *Feb 15, 1990Feb 11, 1992Nartron CorporationCapacity responsive keyboard
US5153572 *Jun 8, 1990Oct 6, 1992Donnelly CorporationTouch-sensitive control circuit
US5157273 *Jun 8, 1990Oct 20, 1992Donnelly CorporationModular power outlet strip
US5189417 *Oct 16, 1990Feb 23, 1993Donnelly CorporationDetection circuit for matrix touch pad
US5220136 *Nov 26, 1991Jun 15, 1993Elographics, Inc.Contact touchscreen with an improved insulated spacer arrangement
US5228562 *Sep 9, 1991Jul 20, 1993Gm Nameplate, Inc.Membrane switch and fabrication method
US5243162 *Sep 4, 1991Sep 7, 1993Alps Electric Co., Ltd.Transparent touch switch
US5251123 *Aug 13, 1991Oct 5, 1993I C Operating, Inc.High resolution system for sensing spatial coordinates
US5426732 *Oct 5, 1994Jun 20, 1995International Business Machines CorporationMethod and apparatus for user control by deriving next states of a process from a current state and by providing a visual presentation of the derived next states
US5451724 *Jul 30, 1993Sep 19, 1995Fujitsu LimitedTouch panel for detecting a coordinate of an arbitrary position where pressure is applied
US5530209 *Oct 18, 1994Jun 25, 1996Alps Electric Co., Ltd.Coordinate input device and method for manufacturing same
US5541370 *Dec 28, 1992Jul 30, 1996Catalysts & Chemicals Industries Co., Ltd.Pressure-sensitive pad and production thereof
US5550339 *Oct 31, 1994Aug 27, 1996Cts CorporationSensor for sensing intent, direction and magnitude
US5633660 *Apr 28, 1995May 27, 1997Trinitech Systems Inc.Integrated touch screen input device
US5686705 *Feb 15, 1996Nov 11, 1997Explore Technologies, Inc.Surface position location system and method
US5711672 *Jun 30, 1995Jan 27, 1998Tv Interactive Data CorporationMethod for automatically starting execution and ending execution of a process in a host device based on insertion and removal of a storage media into the host device
US5749735 *Nov 3, 1995May 12, 1998Tv Interactive Data CorporationInteractive book, magazine and audio/video compact disk box
US5757304 *Sep 13, 1996May 26, 1998Tv Interactive Data CorporationRemote control including an integrated circuit die supported by a printed publication and method for forming the remote control
US5788507 *Nov 2, 1995Aug 4, 1998Tv Interactive Data CorporationMethod for remotely controlling a display of information from a storage media
US5795156 *Nov 1, 1995Aug 18, 1998Tv Interactive Data CorporationHost device equipped with means for starting a process in response to detecting insertion of a storage media
US5796183 *Jan 31, 1996Aug 18, 1998Nartron CorporationCapacitive responsive electronic switching circuit
US5815141 *Apr 12, 1996Sep 29, 1998Elo Touch Systems, Inc.Resistive touchscreen having multiple selectable regions for pressure discrimination
US5818430 *Jan 24, 1997Oct 6, 1998C.A.M. Graphics Co., Inc.Touch screen
US5839905 *Oct 31, 1995Nov 24, 1998Tv Interactive Data CorporationRemote control for indicating specific information to be displayed by a host device
US5877458 *Nov 21, 1996Mar 2, 1999Kke/Explore Acquisition Corp.Surface position location system and method
US5911582 *Feb 5, 1996Jun 15, 1999Tv Interactive Data CorporationInteractive system including a host device for displaying information remotely controlled by a remote control
US5957695 *Feb 15, 1996Sep 28, 1999Tv Interactive CorporationStructure and method for displaying commercials and sending purchase orders by computer
US6175773Nov 23, 1998Jan 16, 2001Lg Electronics, Inc.High resolution system for sensing spatial coordinates
US6249863May 3, 1999Jun 19, 2001Tv Interactive Data CorporationHost device equipped with means for starting a process in response to detecting insertion of a storage media
US6305073Dec 29, 1999Oct 23, 2001Gm Nameplate, Inc.One-sided electrode arrangement on an intermediate spacer for a touchscreen
US6333736May 20, 1999Dec 25, 2001Electrotextiles Company LimitedDetector constructed from fabric
US6344623Apr 21, 1999Feb 5, 2002Sumitomo Electric Industries, Ltd.Membrane switch and production method thereof
US6369804Apr 23, 1999Apr 9, 2002Eleksen LimitedDetector constructed from fabric having non-uniform conductivity
US6437258Jul 19, 2001Aug 20, 2002Eleksen LimitedDetector constructed from fabric having planes with differing conductance
US6452479May 4, 2000Sep 17, 2002Eleksen LimitedDetector contructed from fabric
US6477274 *Oct 22, 1999Nov 5, 2002Ericsson Inc.Handwritten character recognition devices and electronic devices incorporating same
US6483498Mar 17, 1999Nov 19, 2002International Business Machines CorporationLiquid crystal display with integrated resistive touch sensor
US6492980Jul 19, 2001Dec 10, 2002Eleksen LimitedMultiplexing detector constructed from fabric
US6501465Jul 19, 2001Dec 31, 2002Eleksen LimitedDetector constructed from fabric using measured current to determine pressure
US6504531May 4, 2000Jan 7, 2003Eleksen LimitedDetecting mechanical interactions
US6639162Mar 30, 2001Oct 28, 2003Electrotextiles Company LimitedInput device
US6650319Mar 5, 1999Nov 18, 2003Elo Touchsystems, Inc.Touch screen based topological mapping with resistance framing design
US6650867Nov 16, 2001Nov 18, 2003Smartpaper Networks CorporationRemote control apparatus and method of transmitting data to a host device
US6661405May 19, 2000Dec 9, 2003Leapfrog Enterprises, Inc.Electrographic position location apparatus and method
US6668156Feb 5, 2001Dec 23, 2003Leapfrog Enterprises, Inc.Print media receiving unit including platform and print media
US6714117Jul 24, 2002Mar 30, 2004Eleksen LimitedDetector constructed from fabric
US6861961Mar 30, 2001Mar 1, 2005Electrotextiles Company LimitedFoldable alpha numeric keyboard
US6926106 *May 5, 2003Aug 9, 2005Invacare CorporationWheelchair having speed and direction control touchpad
US6947031Mar 30, 2001Sep 20, 2005Electrotextiles Company LimitedData processing apparatus with replacement keyboard
US6968151Oct 16, 2003Nov 22, 2005Smartpaper Networks CorporationRemote control
US6985139Jan 5, 2004Jan 10, 2006Leapfrog Enterprises, Inc.Interactive apparatus using print media
US7006786Jun 4, 2003Feb 28, 2006Tinkers & ChanceComputer software and portable memory for an electronic educational toy
US7018213Dec 29, 2003Mar 28, 2006Tinkers & ChanceElectronic educational toy teaching letters words, numbers and pictures
US7029283Dec 29, 2003Apr 18, 2006Tinkers & ChanceElectronic educational toy
US7039355Mar 11, 2003May 2, 2006Leapfrog Enterprises, Inc.Print media receiving unit including platform and print media
US7040898Dec 29, 2003May 9, 2006Tinkers & ChanceComputer software and portable memory for an electronic educational toy
US7068262Jun 9, 2003Jun 27, 2006Leapfrog Enterprises, Inc.Writing stylus for electrographic position location apparatus
US7102614May 30, 2001Sep 5, 2006Eleksen LimitedManual input apparatus for a handheld device
US7120386Mar 11, 2003Oct 10, 2006Leapfrog Enterprises, Inc.Print media receiving unit including platform and print media
US7139523Mar 11, 2003Nov 21, 2006Leapfrog Enterprises, Inc.Print media receiving unit including platform and print media
US7161084Mar 30, 2001Jan 9, 2007Electrotextiles Company LimitedDetector constructed from electrically conducting fabric
US7203455May 30, 2003Apr 10, 2007Mattel, Inc.Interactive multi-sensory reading system electronic teaching/learning device
US7214066Jan 12, 2004May 8, 2007Tinkers & ChanceComputer software and portable memory for an electronic educational toy having a contact sensitive display screen
US7217135Jan 12, 2004May 15, 2007Tinkers & ChanceElectronic educational toy having a contact-sensitive display screen
US7265686Jul 15, 2003Sep 4, 2007Tyco Electronics CorporationTouch sensor with non-uniform resistive band
US7289111 *Mar 25, 2004Oct 30, 2007International Business Machines CorporationResistive touch pad with multiple regions of sensitivity
US7299971Apr 22, 2004Nov 27, 2007Leapfrog Enterprises, Inc.Print media information systems and methods
US7365031Apr 2, 2001Apr 29, 2008Intelligent Textiles LimitedConductive pressure sensitive textile
US7402042May 30, 2003Jul 22, 2008Mattel, Inc.Electronic learning device for an interactive multi-sensory reading system
US7499036Sep 12, 2003Mar 3, 2009Leapfrog Enterprises, Inc.Electrographic position location apparatus and method
US7557939Apr 22, 2004Jul 7, 2009Leapfrog Enterprises, Inc.Print media information systems and methods
US7567242May 23, 2007Jul 28, 2009Leapfrog Enterprises, Inc.Writing stylus
US7800589Dec 6, 2000Sep 21, 2010Tyco Electronics CorporationTouch screen with relatively conductive grid
US7831933Jan 12, 2005Nov 9, 2010Leapfrog Enterprises, Inc.Method and system for implementing a user interface for a device employing written graphical elements
US7853193Nov 1, 2005Dec 14, 2010Leapfrog Enterprises, Inc.Method and device for audibly instructing a user to interact with a function
US7883420Sep 11, 2006Feb 8, 2011Mattel, Inc.Video game systems
US7916124May 3, 2006Mar 29, 2011Leapfrog Enterprises, Inc.Interactive apparatus using print media
US7922099Dec 30, 2005Apr 12, 2011Leapfrog Enterprises, Inc.System and method for associating content with an image bearing surface
US7936339Nov 1, 2005May 3, 2011Leapfrog Enterprises, Inc.Method and system for invoking computer functionality by interaction with dynamically generated interface regions of a writing surface
US7941090Jan 16, 2004May 10, 2011Shoot The Moon Products Ii, LlcInteractive book reading system using RF scanning circuit
US8261967Jul 19, 2006Sep 11, 2012Leapfrog Enterprises, Inc.Techniques for interactively coupling electronic content with printed media
US8298968Feb 25, 2005Oct 30, 2012Intelligent Textiles LimitedElectrical components and circuits constructed as textiles
US8535153Dec 27, 2010Sep 17, 2013Jonathan BradburyVideo game system and methods of operating a video game
US8599143Feb 6, 2006Dec 3, 2013Leapfrog Enterprises, Inc.Switch configuration for detecting writing pressure in a writing device
US8669195Sep 27, 2012Mar 11, 2014Intelligent Textiles LimitedElectrical components and circuits constructed as textiles
USRE38286Feb 28, 2001Oct 28, 2003Leapfrog Enterprises, Inc.Surface position location system and method
USRE39881Sep 18, 2003Oct 16, 2007Leapfrog Enterprises, Inc.Surface position location system and method
EP0054406A1 *Dec 9, 1981Jun 23, 1982Moore Business Forms, Inc.Writing pad for a character recognition device
EP0145651A2 *Oct 9, 1984Jun 19, 1985Battelle Memorial InstituteDevice for forming signals characteristic of the position of a predetermined point on a surface
EP0194861A2 *Mar 11, 1986Sep 17, 1986Elographics, Inc.Electrographic touch sensor with z-axis capability
EP0210063A2 *Jul 18, 1986Jan 28, 1987Elographics, Inc.Fabric touch sensor & method of manufacture
EP0301842A2 *Jul 27, 1988Feb 1, 1989Toppan Moore Company, Ltd.Information input sheet
EP0419145A1 *Sep 14, 1990Mar 27, 1991Psion PlcInput device
EP0625789A1 *Dec 28, 1992Nov 23, 1994CATALYSTS & CHEMICALS INDUSTRIES CO., LTD.Writing pad and production thereof
WO1989000442A1 *Jul 4, 1988Jan 26, 1989Peter CzwalinaElectric monitoring of surfaces, in particular the boundary surfaces of sports grounds
WO1994018664A1 *Feb 14, 1994Aug 18, 1994Trinitech Systems IncAn integrated touch screen input device
WO1997030429A1 *Feb 11, 1997Aug 21, 1997Explore Technologies IncSurface position location system and method
WO2000002217A1 *Apr 21, 1999Jan 13, 2000Yutaka FukudaMembrane switch and production method thereof
WO2005010804A1 *Jun 25, 2004Feb 3, 2005Donald W BouldinTouch sensor with non-uniform resistive band
Classifications
U.S. Classification178/18.5, 200/86.00R
International ClassificationG06F3/045, G06F3/033, G06F3/041
European ClassificationG06F3/045