Resistive touch screen having conductive mesh

• US 7,196,281 B2
• Filed: 11/12/2004
• Issued: 03/27/2007
• Est. Priority Date: 11/12/2004
• Status: Active Grant

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Majumdar, Debasis, Cok, Ronald S., Irvin, Glen C. Jr.
• Primary Examiner(s): LEE, KYUNG S
• Application Number:
  US10/987,882
• Publication Number:
  US 20060102461A1
• Time in Patent Office: 865 Days
• Field of Search: 200/5.R, 200/600, 200511-512, 200/514, 296/22, 345/168, 345/173, 345174-175
• US Class Current: 200/512
• 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: Y10T 29/49105 Switch making

Abstract

A touch screen comprising: a) a substrate; b) a first conductive layer located on the substrate; c) a flexible sheet comprising a substantially planar surface and integral compressible spacer dots formed thereon, each integral compressible spacer dot having a base closest to the planar surface and a peak furthest from the planar surface; and d) a second conductive layer located on the surface of the flexible sheet, wherein the second conductive layer comprises a conductive mesh pattern and the peaks of the integral compressible spacer dots are located in non-conductive openings in the conductive mesh pattern; wherein when a minimum required activation force is applied to the touch screen at the location of one of the compressible spacer dots, the compressible spacer dot is compressed to allow electrical contact between the first and second conductive layers.

Claims

1. A touch screen comprising:

a) a substrate;

b) a first conductive layer located on the substrate;

c) a flexible sheet comprising a substantially planar surface and integral compressible spacer dots formed thereon, each integral compressible spacer dot having a base closest to the planar surface and a peak furthest from the planar surface; and

d) a second conductive layer located on the surface of the flexible sheet, wherein the second conductive layer comprises a conductive mesh pattern and the peaks of the integral compressible spacer dots are located in non-conductive openings in the conductive mesh pattern;

wherein the first and second conductive layers are positioned towards each other and separated by the integral compressible spacer dots, whereby, when a minimum required activation force is applied to the touch screen at the location of one of the compressible spacer dots, the compressible spacer dot is compressed to allow electrical contact between the first and second conductive layers.

2. The resistive touch screen of claim 1, wherein the substrate, first conductive layer, flexible cover sheet, and second conductive layer are transparent.

3. The touch screen of claim 1 wherein the integral compressible spacer dots are not coated with an electrical conductor.

4. The touch screen of claim 1 wherein the integral compressible spacer dots are at least partially coated with an electrically conductive material not in electrical contact with the second conductive layer mesh pattern located on the surface of the flexible sheet.

5. The touch screen of claim 1 wherein the conductive mesh forms a regular pattern.

6. The touch screen of claim 1 wherein the conductive mesh forms a rectangular pattern having conductive lines around the perimeter of the rectangle and a non-conductive area within the rectangle.

7. The touch screen of claim 6 wherein the integrated compressible spacer dots are located within the rectangle.

8. The touch screen of claim 1 wherein the conductive mesh forms a pattern having first non-conductive areas of a first size surrounded by a conductive area and second non-conductive areas of a second size surrounded by a conductive area.

9. The touch screen of claim 8 wherein the integrated compressible spacer dots are located within the second non-conductive areas.

10. The touch screen of claim 1 wherein the integrated compressible spacer dots are larger than the non-conductive openings.

11. The touch screen of claim 1, wherein the flexible sheet comprises one of the group including:

polymer, polyolefin polymer, polyester, polycarbonate, and a blend of polyester and polycarbonate.

12. The touch screen of claim 1, wherein the integral compressible spacer dots comprise cylinder-shaped dots, cube-shaped dots, pyramid-shaped dots, cone-shaped dots, or sphere-shaped dots.

13. The touch screen of claim 1, wherein the substrate comprises a rigid material.

14. The touch screen of claim 1, wherein the second conductive layer comprises an electrically conductive polymer.

15. The touch screen of claim 14, wherein the conductive layer comprises one of the group including polypyrrole styrene sulfonate, 3,4-dialkoxy substituted polypyrrole styrene sulfonate, and 3,4-dialkoxy substituted polythiophene styrene sulfonate, poly(3,4-ethylene dioxythiophene styrene sulfonate.

16. The touch screen of claim 14, wherein the conductive layer comprises polythiophine.

17. The touch screen claimed in claim 1 wherein the substrate is flexible.

18. The touch screen claimed in claim 1 wherein the substrate is rigid.

19. The touch screen of claim 1 wherein the touch screen substrate is a cover or substrate of a flat-panel display device.

20. The touch screen claimed in claim 19, wherein the flat-panel display device is an OLED display device.

21. The touch screen claimed in claim 19, wherein the flat-panel display device is a liquid crystal display device.

22. The touch screen of claim 1 wherein the touch screen substrate is a cover or substrate of a flat-panel lamp.

23. The touch screen claimed in claim 22, wherein the flat-panel lamp is an OLED lamp.

24. The resistive touch screen of claim 1, wherein the conductive layer comprises indium tin oxide.

25. A method of making a touch screen, comprising the steps of:

a) providing a substrate;

b) forming a first conductive layer on the substrate;

c) providing a flexible cover sheet comprising a substantially planar surface and integral compressible spacer dots formed thereon, each integral compressible spacer dot having a base closest to the planar surface and a peak furthest from the planar surface;

d) forming a second conductive layer on the flexible cover sheet in a conductive mesh pattern, such that the peaks of the integral compressible spacer dots are located in non-conductive openings in the conductive mesh pattern; and

e) locating the flexible cover sheet over the substrate such that the first and second conductive layers are positioned towards each other and separated by the integral compressible spacer dots, and such that when a force is applied to the flexible cover sheet at the location of one of the integral compressible spacer dots, the integral compressible spacer dot is compressed to allow electrical contact between the first and second conductive layers.

26. The method of claim 25 wherein the flexible sheet is provided as a web in a continuous roll, the integral spacer dots are molded in the continuous roll, and the sheet is cut from the roll.

27. The method of claim 25 wherein the spacer dots are formed in the flexible sheet by injection roll molding.

28. The method of claim 25, wherein the spacer dots are formed in the flexible sheet by applying heat and pressure to the flexible sheet by a mold including a reverse image of the spacer dots.

29. The method of claim 25, wherein conductive material is deposited through a mask to form the second conductive layer mesh pattern.

30. The method of claim 25, wherein conductive material is deposited using inkjet printing to form the second conductive layer mesh pattern.

31. The method of claim 25, wherein conductive material is deposited via contact printing to form the second conductive layer mesh pattern.

32. The method of claim 25, wherein conductive material is deposited in a continuous coating on the flexible sheet and cured in a pattern to form the second conductive layer mesh pattern.

33. The method of claim 32, wherein non-cured coating is removed from the flexible cover sheet.