Resistive touch panel using removable, tensioned top layer

• US 6,664,950 B1
• Filed: 11/17/1999
• Issued: 12/16/2003
• Est. Priority Date: 11/17/1999
• Status: Expired due to Fees

• Current Assignee: L-3 Communications Corporation (L3Harris Technologies, Inc.)
• Original Assignee: L-3 Communications Corporation (L3Harris Technologies, Inc.)
• Inventors: Blanchard, Randall D.
• Primary Examiner(s): WU, XIAO MIN
• Application Number:
  US09/442,227
• Time in Patent Office: 1,490 Days
• Field of Search: 345/173, 345/174, 345/176, 345/177, 345/178, 345/179, 345/175, 178/18.01, 178/18.1, 359/580
• US Class Current: 345/173
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

Sunlight can damage a conventional touch screen display and cause the display to be quite difficult to read. Furthermore, conventional touch screen displays are easily damaged, and, once damaged, the entire touch screen is replaced. To address these concerns, a touch panel includes anti-reflective coatings on the surfaces of the top plate and the base plate that are open to the air. These coatings substantially reduce reflections and make the touch screen easier to read in direct sunlight. In particular, the anti-reflective coating used on the upper surface of the base plate is dielectric in nature to reduce reflectivity even further. This dielectric coating includes openings to an underlying conductive layer so that an electrical contact is made when a user deflects the top plate into the base plate. Also, the top plate may be detachably coupled to the base plate, advantageously by double stick adhesive tape, so that only the top plate is replaced when damaged. In one embodiment, the top plate is placed in tension within a frame to prevent wrinkling. Furthermore, a resistive voltage divider may be fabricated on the base plate. The resistive voltage divider may include a substantially continuous strip of resistive material disposed on the conductive layer of the base plate, and a plurality of conductive traces disposed on the dielectric layer of the base plate and coupled to the resistive material in selected locations.

Claims

1. A touch screen overlay comprising:

a tensioning frame;

a flexible substrate having an upper surface and a lower surface, upper surface coupled to the tensioning frame; and

double stick adhesive tape coupled to the lower surface of the flexible substrate, wherein the double stick adhesive tape comprises a relatively high tack adhesive side and a relatively low tack adhesive side.

2. The overlay, as set forth in claim 1, comprising a hard coating layer disposed over the upper surface of the flexible substrate.

3. The overlay, as set forth in claim 2, wherein the hard coating layer comprises silicon dioxide.

4. The overlay, as set forth in claim 1, wherein the flexible substrate comprises one of Mylar, Lexan, and CR-39.

5. The overlay, as set forth in claim 1, comprising an anti-reflective layer disposed over the upper surface of the flexible substrate.

6. The overlay, as set forth in claim 5, wherein the anti-reflective layer comprises at least one of silicon dioxide and magnesium fluoride.

7. The overlay, as set forth in claim 1, comprising an anti-reflective conductive layer disposed on the lower surface of the flexible substrate.

8. The overlay, as set forth in claim 7, wherein the anti-reflective conductive layer comprises at least one of titanium and indium tin oxide.

9. The overlay, as set forth in claim 1, herein the relatively high tack adhesive side is coupled to the flexible substrate.

10. The overlay, as set forth in claim 1, wherein the relatively low tack adhesive side is coupled to the flexible substrate.

11. The overlay, as set forth in claim 1, comprising an anti-fingerprint layer disposed over the flexible substrate.

12. The overlay, as set forth in claim 11, wherein the anti-fingerprint layer comprises a hydrophobic material.

13. The overlay, as set forth in claim 1, wherein the tensioning frame comprises a reinforced material.

14. The overlay, as set forth in claim 1, wherein the tensioning frame comprises a metal.

15. The overlay, as set forth in claim 14, wherein the tensioning frame comprises one of aluminum and stainless steel.

16. The overlay, as set forth in claim 1, wherein the tensioning frame is bonded to an outer surface of the top plate.

17. The overlay, as set forth in claim 16, wherein the tensioning frame is bonded to an outer surface of the top plate with a UV curing adhesive.

18. The overlay, as set forth in claim 1, comprising a coating which reflects solar energy outside the visible spectrum disposed over the flexible substrate.

19. The overlay, as set forth in claim 18, wherein the coating which reflects solar energy outside the visible spectrum comprises a hot mirror capability.

20. A touch screen comprising:

a tensioning frame;

a top plate having an upper surface and a lower surface, the upper surface being coupled to the tensioning frame;

a base plate having an upper surface and a lower surface; and

a member having a high tack adhesive surface and a low tack adhesive surface detachably coupling the lower surface of the top plate to the upper surface of the base plate.

21. The touch screen, as set forth in claim 20, wherein the top plate comprises a flexible substrate having an upper surface and a lower surface.

22. The touch screen, as set forth in claim 21, wherein the flexible substrate comprises one of Mylar, Lexan, and CR-39.

23. The touch screen, as set forth in claim 21, comprising a hard coating layer disposed over the upper surface of the flexible substrate.

24. The touch screen, as set forth in claim 23, wherein the hard coating layer comprises silicon dioxide.

25. The touch screen, as set forth in claim 21, comprising an anti-reflective layer disposed over the upper surface of the flexible substrate.

26. The touch screen, as set forth in claim 25, wherein the anti-reflective layer comprises at least one of silicon dioxide and magnesium fluoride.

27. The touch screen, as set forth in claim 21, comprising an anti-reflective conductive layer disposed on the lower surface of the flexible substrate.

28. The touch screen, as set forth in claim 27, wherein the anti-reflective conductive layer comprises at least one of titanium and indium tin oxide.

29. The touch screen, as set forth in claim 20, wherein the member comprises double stick adhesive tape having the low tack adhesive surface and the high tack adhesive surface.

30. The touch screen, as set forth in claim 20, wherein the relatively high tack adhesive surface is coupled to the lower surface of the top plate and the relatively low tack adhesive surface is coupled to the upper surface of the base plate.

31. The touch screen, as set forth in claim 20, wherein the relatively low tack adhesive surface is coupled to the lower surface of the top plate and the relatively high tack adhesive surface is coupled to the upper surface of the base plate.

32. The touch screen, as set forth in claim 21, comprising an anti-fingerprint layer disposed over the flexible substrate.

33. The touch screen, as set forth in claim 32, wherein the anti-fingerprint layer comprises a hydrophobic material.

34. The touch screen, as set forth in claim 20, wherein the tensioning frame comprises the reinforced material.

35. The touch screen, as set forth in claim 20, wherein the tensioning frame comprises a metal.

36. The touch screen, as set forth in claim 35, wherein the tensioning frame comprises one of aluminum and stainless steel.

37. The touch screen, as set forth in claim 20, wherein the tensioning frame is bonded to an outer surface of the top plate.

38. The touch screen, as set forth in claim 37, wherein the tensioning frame is bonded to an outer surface of the top plate with a UV curing adhesive.

39. The touch screen, as set forth in claim 21, comprising a coating which reflect solar energy outside the visible spectrum disposed over the flexible substrate.

40. The touch screen, as set forth in claim 39, wherein the coating which reflects solar energy outside the visible spectrum comprises a hot mirror capability.

41. The touch screen, as set forth in claim 20, wherein the base plate comprises a rigid substrate having an upper surface and a lower surface.

42. The touch screen, as set forth in claim 41, comprising a conductive layer disposed over the upper surface of the rigid substrate.

43. The touch screen, as set forth in claim 42, wherein the conductive layer comprises at least one of titanium and indium tin oxide.

44. The touch screen, as set forth in claim 42, comprising an anti-reflective dielectric layer disposed over the conductive layer, the anti-reflective dielectric layer having openings through to the conductive layer.

45. The touch screen, as set forth in claim 44, wherein the anti-reflective dielectric layer comprises one of silicon dioxide and magnesium fluoride.

46. The touch screen, as set forth in claim 41, comprising an anti-reflective layer disposed on the lower surface of the rigid substrate.

47. The touch screen, as set forth in claim 46, wherein the anti-reflective layer comprises multiple layers of anti-reflective material.

48. The touch screen, as set forth in claim 20, comprising a sensing circuit coupled to the top plate and to the base plate, the sensing circuit delivering a signal correlative to a position where the top plate contacts the base plate.

49. The touch screen, as set forth in claim 48, wherein the sensing circuit comprises:

a substantially continuous resistive member disposed on a conductive layer on the base plate adjacent a peripheral portion of a patterned anti-reflective dielectric layer disposed over the conductive layer on the base plate; and

a plurality of conductive traces disposed on the anti-reflective dielectric layer, each of the plurality of conductive traces having a first end coupled to a respective selected location of the resistive member.