Touch panel with improved optical performance

• US 6,512,512 B1
• Filed: 07/31/1999
• Issued: 01/28/2003
• Est. Priority Date: 07/31/1999
• Status: Expired due to Fees

• Current Assignee: L-3 Communications Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Litton Systems Incorporated
• Inventors: Blanchard, Randall D.
• Primary Examiner(s): NGUYEN, CHANH DUY
• Application Number:
  US09/364,988
• Time in Patent Office: 1,277 Days
• Field of Search: 345/173,174,175 341/21-23,34 178/18.01,18.03 359/580,581,586,589 430/156,157 349/104,105 40/152,600
• US Class Current: 345/173
• CPC Class Codes: G02B 1/116 including electrically conducting layers
• 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. 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 exposing an open area between about 1% and about 5% of 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 and a second anti-reflective layer 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 the rigid substrate comprises glass.

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

13. The system, as set fort in claim 12, wherein the first substrate portion and the second substrate portion comprise glass.

14. 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.

15. The system, as set forth in claim 14, wherein the coating which reflects solar energy comprises a hot mirror capability.

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

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

18. 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.

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

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

21. The overlay, as set forth in claim 20, comprising a second hard coating layer disposed over the upper surface of the flexible substrate.

22. The overlay, as set forth in claim 21, wherein at least one of the hard coating layer and the second hard coating layer comprises silicon dioxide.

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

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

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

26. The touch panel display system, as set forth in claim 1, wherein the openings are etched through the anti-reflective dielectric layer.

27. The touch panel display system, as set forth in claim 1, wherein the first conductive layer and the anti-reflective dielectric layer comprise a standard multi-layer anti-reflective coating, and the openings comprise a subsequently removed hole pattern.

28. The touch panel display system, as set forth in claim 1, wherein the top plate is detachably coupled to the base plate via a removable attachment mechanism comprising:

at least one spacer to space the top plate from the base plate; and

at least one removable fastener to couple the top plate, the base plate, and the at least one spacer together.

29. The touch panel display system, as set forth in claim 28, wherein the at least one removable fastener comprises a bolt.

30. A panel display, comprising:

a flexible outer panel; and

a rigid inner panel offset from the flexible outer panel and comprising an anti-reflective coating having an outer anti-reflective dielectric layer and an inner conductive layer, wherein the outer anti-reflective dielectric layer comprises a pattern of openings extending through to the inner conductive layer exposing an area between about 1% and about 5% of the inner conductive layer.

31. The panel display of claim 30, wherein the flexible outer panel is a touch screen panel.

32. The panel display of claim 30, wherein the flexible outer panel is removably coupled to the rigid inner panel via a removable attachment mechanism.

33. The panel display of claim 32, wherein the removable attachment mechanism comprises an adhesive tape having a low tack adhesive side and a high tack adhesive side.

34. The panel display of claim 32, wherein the removable attachment mechanism comprises:

at least one spacer to space the flexible outer panel from the rigid inner panel; and

at least one removable fastener to couple the flexible outer panel, the rigid inner panel, and the at least one spacer together.

35. The panel display of claim 34, wherein the at least one removable fastener comprises a bolt.