Resistive touch panel using removable, tensioned top layer

• US 7,071,927 B2
• Filed: 08/12/2003
• Issued: 07/04/2006
• 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
• Application Number:
  US10/639,280
• Publication Number:
  US 20040095332A1
• Time in Patent Office: 1,057 Days
• Field of Search: 345173-179, 178/18.01, 178/18.1, 178/19.01
• 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 panel display system comprising:

a computer;

a controller coupled to the computer;

a display screen coupled to the computer;

a touch panel coupled to the controller and being disposed over the display screen, the touch panel comprising;

a base plate being disposed adjacent the display screen, the base plate having a rigid substrate having an upper surface and a lower surface, a first conductive layer disposed over the upper surface of the rigid substrate, an anti-reflective dielectric layer disposed over the first conductive layer, the anti-reflective dielectric layer having openings through to the first conductive layer, and a first anti-reflective layer disposed on the lower surface of the rigid substrate; and

a top plate being disposed in spaced apart relation over the base plate, the top plate having a flexible substrate having an upper surface and a lower surface, a hard coating layer, a second anti-reflective layer, and a tensioning frame disposed over the upper surface of the flexible substrate, and an anti-reflective conductive layer disposed on the lower surface of the flexible substrate.

2. The system, as set forth in claim 1, wherein the display screen comprises a liquid crystal display.

3. The system, as set forth in claim 1, wherein the top plate is removably mounted in spaced apart relation over the base plate.

4. The system, as set forth in claim 3, comprising double stick adhesive tape coupling the top plate to the base plate.

5. The system, as set forth in claim 4, wherein the double stick adhesive tape comprises a relatively high tack adhesive side and a relatively low tack adhesive side.

6. The system, as set forth in claim 5, wherein the relatively high tack adhesive side is coupled to the top plate and the relatively low tack adhesive side is coupled to the base plate.

7. The system, as set forth in claim 5, wherein the relatively high tack adhesive side is coupled to the base plate and the relatively low tack adhesive side is coupled to the top plate.

8. The system, as set forth in claim 1, wherein the second anti-reflective layer is disposed over the hard coating layer.

9. The system, as set forth in claim 1, wherein the top plate comprises an anti-fingerprint layer disposed over the second anti-reflective layer and the hard coating layer.

10. The system, as set forth in claim 1, wherein the anti-fingerprint layer comprises a hydrophobic material.

11. The system, as set forth in claim 1, wherein a-the tensioning frame comprises the reinforced material.

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

13. The system, as set forth in claim 12, wherein the tensioning frame comprises one of aluminum and stainless steel.

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

15. The system, as set forth in claim 14, wherein the tensioning frame is bonded to an outer surface of the top plate with a UV curing adhesive.

16. The system, as set forth in claim 1, wherein the rigid substrate comprises glass.

17. The system, as set forth in claim 1, wherein the rigid substrate comprises a first substrate portion bonded to a second substrate portion.

18. The system, as set fort in claim 17, wherein the first substrate portion and the second substrate portion comprise glass.

19. The system, as set forth in claim 1, comprising a coating which reflects solar energy outside the visible spectrum disposed on at least one of the top plate and the base plate.

20. The system, as set forth in claim 19, wherein the coating which reflects solar energy comprises a hot mirror capability.

21. The system, as set forth in claim 1, wherein the first conductive layer comprises at least one of titanium and indium tin oxide.

22. The system, as set forth in claim 1, wherein the anti-reflective dielectric layer comprises at least one of silicon dioxide and magnesium fluoride.

23. The system, as set forth in claim 1, wherein each opening has an area in a range from about 2.5 mils to about 10.0 mils, and wherein the openings have an average spacing in a range from about 10.0 mils to about 50.0 mils.

24. The system, as set forth in claim 1, wherein the first anti-reflective layer comprises multiple layers.

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

26. The system, as set forth in claim 1, wherein the hard coating layer comprises silicon dioxide.

27. The system, as set forth in claim 1, wherein the second anti-reflective layer comprises at least one of silicon dioxide and magnesium fluoride.

28. The system, as set forth in claim 1, wherein the anti-reflective conductive layer comprises at least one of titanium and indium tin oxide.

29. The system, as set forth in claim 1, wherein the touch panel comprises a sensing circuit coupled to the first conductive layer and to the anti-reflective conductive layer, the sensing circuit delivering a signal correlative to a position where the first conductive layer contacts the anti-reflective conductive layer.

30. The system as set forth in claim 29, wherein the sensing circuit comprises:

a substantially continuous resistive member disposed on the first conductive layer adjacent a peripheral portion of the anti-reflective dielectric layer; 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 and having a second end coupled to the controller.