Solid state image detector and signal generator

• US 4,827,084 A
• Filed: 11/19/1987
• Issued: 05/02/1989
• Est. Priority Date: 11/19/1987
• Status: Expired due to Term

• Current Assignee: Guardian Industries Corporation (KOCH Industries Incorporated)
• Original Assignee: OIS Optical Imaging Systems, Inc. (KOCH Industries Incorporated)
• Inventors: McGill, John C., Prewarski, Mike, Mulberger, Ronald G., Yaniv, Zvi, Catchpole, Clive, Cannella, Vincent D.
• Primary Examiner(s): SCHREYER, STAFFORD
• Application Number:
  US07/122,990
• Time in Patent Office: 530 Days
• Field of Search: 178/18, 178/19, 252/62.3 R, 252/62.3 V
• US Class Current: 178/18.05
• CPC Class Codes: G06F 3/033 Pointing devices displaced or positioned by the user , e.g. mice, trackballs, pens or joysticks; Accessories therefor digitisers characterised by the transducing means G06F3/041
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact
• CPC Class Codes: G09B 5/14 with provision for individual teacher-student communication

Abstract

A solid state, touch sensitive position sensor, which sensor includes a conductive surface along the boundaries of which are disposed at least two sets of two elongated current distribution and collection means. The touch sensitive position sensor further includes resistance means operatively disposed so as to interconnect said current distribution and collection means with said conductive surface. The current distribution and collection means and resistance means are configured, so as to (1) provide a substantially linear electric field distribution of equipotential lines and (2) sequentially turn one set of said current distribution and collection means on while turning the other sets off. In an important embodiment, the conductive surface is formed immediately atop a copyboard and by utilizing erasable, felt tip markers having metallic inserts therein, visual images as well as electrical signals, indicative of X-Y coordinate location, may be simultaneously generated.

Claims

1. A touch sensitive position sensor for detecting the location of a touch point thereupon, comprising:

a. a transparent conductive oxide conductive surface;

b. at least two pairs of elongated distributed diode current distribution and collection means, the members of each pair being substantially parallel to, facing, and spaced apart from each other on said conductive surface so as to establish an electric field thereacross, said distributed diode current distribution and collection means comprising a plurality of vertically superposed, substantially coextensive thin film layers of semiconductor alloy material deposited upon a substrate;

c. current control means, operatively associated with said elongated distributed diode current distribution and collection means, to sequentially turn on one pair of said elongated distributed diode current distribution and collection means and simultaneously turn off another pair of said elongated distributed diode current distribution and collection means; and

d. means for determining the distribution of the electric field across the conductive surface and correlating the distribution of the electric field with the location of the touch point.

2. A sensor as in claim 1 further including electrical resistance means electrically in series with and interconnecting said distributed diode current distribution and collection means and said transparent conductive oxide conductive surface to assure that the flow of current remains substantially upon the transparent conductive oxide conductive surface of the touch position sensor.

3. A sensor as in claim 2, wherein said resistance means provides a resistance of 10 to 1000 ohms, in series with said current distribution and collection means and said conductive surface.

4. A sensor as in claim 3, wherein said resistance is between about 50 to 500 ohms.

5. A sensor as in claim 2 wherein the electrical resistance means electrically interconnect said distributed diode current distribution and collection means with said transparent conductive oxide conductive surface;

said electrical resistance means having an inherent resistance of 50 to 500 ohms.

6. A sensor as in claim 5, wherein said electrical resistance means are formed of a graphitic material.

7. A sensor as in claim 1, wherein said distributed diode means further includes overvoltage protection means operatively associated therewith, said protection means adapted to inhibit the deleterious effects of electrostatic discharge.

8. A sensor as in claim 7, wherein said protection means comprise a chalcogenide glass threshold switch.

9. A sensor as in claim 7, wherein said protection means comprise a Zener diode interposed between said conductive surface and said distributed diode.

10. A sensor as in claim 1, wherein one of a set of said current distribution and collection means include superposed layers of PIN semiconductor alloy material and the other of said set of current distribution and collection means include superposed layers of NIP semiconductor alloy material.

11. A sensor as in claim 1, wherein said current distribution and collection means are disposed along each of the boundaries of the bounded conductive surface.

12. A sensor as in claim 11, wherein the bounded surface is configured as a substantially planar, four sided rectangle;

whereby a touch point on that surface may be uniquely defined by an X-Y coordinate.

13. A sensor as in claim 1, wherein the current distribution and collection means are electrically connected directly to said bounded conductive surface, by means of an electrically conductive adhesive material.

14. A sensor as in claim 1, wherein said distribution determining and correlating means communicates with an output display device, said display device selected from the group consisting of:

computer means, monitor means, memory means, liquid crystal display means, printer means, modem means and copier means.

15. A sensor as in claim 1, wherein said distributed diode means have a characteristic I-V curve;

said distributed diode means adapted to operate within the linear section of said characteristic I-V curve.

16. A sensor as in claim 14, wherein said conductive surface is transparent and disposed immediately atop said output display device.

17. A sensor as in claim 1, further including marker means for providing a visually detectable mark on said bounded conductive surface and including metallic means for creating an electronic touch point upon said surface.

18. A sensor as in claim 17, wherein said marker further includes means for providing a signal indicative of the color thereof.

19. A sensor as in claim 17, further including electrical erasure means adapted to simultaneously erase marks formed on said bounded conductive surface and on the display associated therewith.

20. A sensor as in claim 1, wherein said transparent conductive oxide is selected from the group consisting essentially of indium tin oxide, tin oxide, zinc oxide, antimony doped tin oxide, and combinations thereof.

21. A touch position sensor as in claim 1 further including anisotropically conducting electrical resistance means electrically in series with and interconnecting said distributed diode current distribution and collection means and said transparent conductive oxide conductive surface to assure that the flow of current remains substantially upon the transparent conductive oxide conductive surface of the touch position sensor.