Contrast enhancing transparent touch panel device

• US 4,958,148 A
• Filed: 01/22/1988
• Issued: 09/18/1990
• Est. Priority Date: 03/22/1985
• Status: Expired due to Term

• Current Assignee: Elmwood Sensors Incorporated
• Original Assignee: Elmwood Sensors Incorporated
• Inventors: Olson, Jan B.
• Primary Examiner(s): OBERLEY, ALVIN E
• Application Number:
  US07/147,627
• Time in Patent Office: 970 Days
• Field of Search: 340/365 R, 340/365 S, 340/365 C, 340/712, 340/34, 340/711, 340/22, 179/18, 179/19, 200/5 A, 200/159 B, 200/512, 358/245, 358/252, 358/253, 358/255, 358/247, 296/97 F, 296/97.1, 296/97.2, 296/97.3, 350/276 R, 341/20, 341/22
• US Class Current: 345/174
• CPC Class Codes: H01H 13/702 with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
• CPC Class Codes: H01H 2231/004 CRT
• CPC Class Codes: H01J 29/185 measures against halo-phenomena
• CPC Class Codes: H01J 29/898 Spectral filters

Abstract

A contrast enhancing, substantially transparent touch panel device comprises a static element, a dynamic element and a microweave screen of a fine mesh of fine dark-colored filaments embedded within a clear adhesive layer and incorporated as an integral part of the dynamic element of the panel. Preferably there is no air gap between the front of the device and the conductive surface of the dynamic element. The device can comprise at least one layer of transparent colored coating for light attentuation, color-selective light filtering, and tint correction.

Claims

1. A contrast enhancing, substantially transparent touch panel device comprising:

(a) a transparent touch panel comprising;

(i) a first transparent, electrically conductive layer;

(ii) a flexible second transparent electrically conductive layer facing, spaced apart from, parallel to, and in close proximity to the first conductive layer, the second conductive layer being selectively displaceable so as to contact the first conductive layer at selected points;

(b) a front transparent, flexible, protective layer; and

(c) an antiglare layer held in place by and embedded within a flexible and transparent adhesive, the adhesive being in liquid form when applied and having been cured in situ, the antiglare layer comprising a flexible and transparent fine mesh microweave screen formed of fine dark-colored filaments.

2. The device of claim 1 wherein the antiglare layer is between the front protective layer and the second conductive layer.

3. The device of claim 2 in which the first conductive layer comprises a first transparent plastic film coated with a first transparent film of electrically conductive material and the second conductive layer comprises a flexible second transparent plastic film coated with a flexible second transparent film of electrically conductive material, wherein the two films of electrically conductive material face each other.

4. The device of claim 3 in which the microweave screen is embedded within the adhesive so that there is no air gap between the antiglare layer and the second film, and between the antiglare layer and the front protective layer.

5. The device of claim 1 wherein the front layer is stain and abrasion resistant.

6. The device of claim 1 wherein the adhesive is a silicone elastomer.

7. The device of claim 2 further comprising a flexible transparent plastic film between the front protective layer and the plastic antiglare layer, the protective layer being on the plastic film.

8. The device of claim 1 further comprising at least one transparent colored coating.

9. The device of claim 8 wherein the coating has a grey tint for light attenuation.

10. The device of claim 8 wherein the coating is tinted for color selective light filtering.

11. The device of claim 8 wherein the colored coating is between the front layer and the second conductive layer.

12. The device of claim 1 in which the front layer is colored for light filtering.

13. The device of claim 1 in which the adhesive is colored for light filtering.

14. The device of claim 1 comprising more than one antiglare layer.

15. The device of claim 3 in which the adhesive is the front protective layer.

16. The device of claim 15 wherein there is no air gap between the antiglare layer and the second film.

17. A device as claimed in claim 1 wherein the adhesive forms a layer on both sides of the microweave screen.

18. A device as claimed in claim 1 wherein the adhesive is cured at about room temperature.

19. A contrast enhancing, substantially transparent touch panel device comprising from back to front:

(a) a transparent touch panel comprising;

(i) a static element comprising a first transparent plastic film coated with a first transparent film of electrically conductive material on its front surface,

(ii) a dynamic element comprising a flexible second transparent plastic film coated with a flexible second second transparent film of electrically conductive material on its back surface,

the second conductive film facing, spaced apart from, parallel to, and in close proximity to the first conductive film, the dynamic element being selectively displaceable so that the second conductive film can contact the first conductive film at selected points;

(b) a first antiglare layer comprising a flexible and transparent microweave screen embedded within a flexible and transparent layer of an adhesive, the adhesive having been in liquid form when applied and having been cured in situ to form a solid layer, the adhesive holding the microweave screen to the dynamic element, the screen being a fine mesh formed of fine dark-colored filaments; and

(c) a flexible and transparent front layer of protective material, the front layer being stain and abrasion resistant;

there being no air gap between the front layer and the dynamic element.

20. The device of claim 19 further comprising at least one transparent colored coating for light filtering, said colored coating being between the front layer and the static element.

21. The device of claim 19 wherein the front layer is colored for light filtering.

22. The device of claim 19 wherein the adhesive is colored for light filtering.

23. The device of claim 19 further comprising a flexible and transparent third plastic film between the front layer and the adhesive layer.

24. The device of claim 19 in which the adhesive is the front layer of protective material.

25. A device as claimed in claim 19 wherein the adhesive forms a layer on both sides of the microweave screen.

26. A contrast enhancing, substantially transparent touch panel device comprising:

(a) a transparent touch panel comprising;

(i) a first transparent, electrically conductive layer;

(ii) a flexible second transparent electrically conductive layer facing, spaced apart from parallel to, and in close proximity to the first conductive layer, the second conductive layer being selectively displaceable so as to contact the first conductive layer at selected points;

(b) an antiglare layer held in place by and embedded within a flexible and transparent adhesive, the adhesive being in liquid form when applied and having been cured in situ, the antiglare layer comprising a flexible and transparent fine mesh microweave screen formed of fine dark-colored filaments.

27. The device of claim 26 wherein the adhesive cures in situ to form a stain and abrasion resistant layer.

28. The device of claim 26 wherein the second conductive layer is between the antiglare layer and the first conductive layer.

29. The device of claim 26 further comprising at least one transparent colored coating for light filtering.

30. The device of claim 26 wherein the adhesive is colored for light filtering.

31. The device of claim 28 wherein the adhesive cures to form a stain and abrasion resistant layer.

32. The device of claim 28 further comprising a stain and abrasion resistant, transparent and flexible front protective layer.

33. The device of claim 28 wherein there is no air gap between the antiglare layer and the second conductive layer.

34. A device as claimed in claim 26 wherein the adhesive forms a layer on both sides of the microweave screen.

35. A method for manufacturing a contrast enhanced substantially transparent touch panel device comprising the steps of:

(a) selecting;

(i) a transparent first plastic film;

(ii) a flexible and transparent second plastic film;

(iii) a flexible and transparent third plastic film;

(iv) a first electrically conductive material;

(v) a second electrically conductive material;

(vi) a flexible and transparent microweave screen of a fine mesh of fine dark-colored filaments;

(vii) a clear liquid adhesive capable of curing in situ to form a flexible transparent solid layer;

(viii) a transparent abrasion and stain resistant coating material;

(b) assembling the touch panel device by the steps of;

(i) forming a first transparent film of the first electrically conductive material on the front surface of the first plastic film;

(ii) forming a flexible second transparent film of the second electrically conductive material on the back surface of the second plastic film, the two conductive films being so patterned that together they can form an addressable switch array;

(iii) forming a first laminate by placing the microweave screen between the front surface of the second plastic film and the back surface of the third plastic film with the liquid adhesive therein, applying pressure to the laminate so that there is no air gap between the second and third plastic films and that the screen is embedded within and impregnated with the adhesive, and allowing the adhesive to cure, the first laminate thus formed being flexible;

(iv) applying the abrasion and stain resistant coating material onto the front surface of the third plastic film to form a flexible and transparent front protective layer; and

(v) affixing the first and second plastic films to one another, after the conductive films have been formed on them, so that the second conductive film is facing, spaced apart from, parallel to, and in close proximity to the first conductive film, the first laminate being selectively displaceable so that the second conductive film can contact the first conductive film at selected points on the first conductive film.

36. The method of claim 35 further comprising the steps of selecting and applying at least one transparent colored coating for light filtering.

37. The method of claim 35 wherein the adhesive is a silicone elastomer which is cured at room temperature in the first laminate forming step.

38. The method of claim 35 wherein a colored dye is added to the adhesive before it was applied in the first laminate forming step.

39. A method as claim in claim 35 wherein the adhesive is allowed to cure at about room temperature.

40. A method for manufacturing a contrast enhanced substantially transparent touch panel device comprising the steps of:

(a) selecting;

(i) a transparent first plastic film;

(ii) a flexible and transparent second plastic film;

(iii) a first electrically conductive material;

(iv) a second electrically conductive material;

(v) a flexible and transparent microweave screen of a fine mesh of fine dark-colored filaments;

(vi) a clear liquid adhesive capable of curing in situ to form a flexible transparent solid layer;

(vii) a release sheet capable of being released from the adhesive after the adhesive has cured;

(b) assembling the touch panel device by the steps of;

(i) forming a first transparent film of the first electrically conductive material on the front surface of the first plastic film;

(ii) forming a flexible second transparent film of the second electrically conductive material on the back surface of the second plastic film, the two conductive films being so patterned that together they can form an addressable switch array;

(iii) forming a first laminate by placing the microweave screen between the front surface of the second plastic film and the release sheet with the liquid adhesive therein, applying pressure to the laminate so that there is no air gap between the second plastic film and the release sheet, and so that the screen is embedded within and impregnated with the adhesive, allowing the adhesive to cure, and then releasing the release sheet from the cured adhesive, the first laminate thus formed being flexible;

(iv) affixing the first and second plastic films to one another, after the conductive films have been formed on them, so that the second conductive film is facing, spaced apart from, parallel to, and in close proximity to the first conductive film, the first laminate being selectively displaceable so that the second conductive film can contact the first conductive film at selected points on the first conductive film.

41. The process of claim 40 further comprising the steps of selecting and applying a transparent abrasion and stain resistant coating material on to the front surface of the adhesive after it has cured, to form a flexible and transparent front protective layer.

42. The process of claim 40 wherein the liquid adhesive is capable of curing in situ to form a layer with a stain and abrasion resistant surface.

43. A contrast enhancing substantially transparent touch panel comprising:

(a) a selectively addressable switch array having;

(i) a first electrically conductive means;

(ii) a flexible second electrically conductive means facing, spaced apart from, parallel to, and in close proximity to the first conductive means, the second conductive means being selectively displaceable so as to contact the first conductive means;

(b) an antiglare layer located in front of the second conductive means, said antiglare layer having a contrast enhancement medium whereby ambient light reflected from the conductive means is selectively attenuated by being forced to pass through the contrast enhancement medium at least twice;

(c) holding means for holding the antiglare layer and the switch array in place, said holding means having a layer of adhesive in back of the antiglare layer and bonding the antiglare layer to the second conductive means, the adhesive in liquid form when applied and cured in situ, the adhesive being selected from the group consisting of silicone adhesives and polyurethane adhesives;

(d) a flexible plastic film placed on the outside of the antiglare layer; and

(e) a flexible front layer of protective material, the front layer being stain and abrasion resistant, there being no air gap between the front layer and the second conductive layer, whereby the panel is flexibly responsive to tactile activation.

44. The panel of claim 43 wherein the first and second electrically conductive means are separate layers of electrically conductive material.

45. The panel of claim 43 wherein the first electrically conductive mean sis a static element having a first plastic film coated with a first membrane of electrically conductive material on its front surface, and the second electrically conductive means is a dynamic element having a flexible second plastic film coated with a flexible second membrane of electrically conductive material on its back surface.

46. The panel of claim 45 in which the first and second plastic films are polyethylene terephthalate.

47. The panel of claim 45 in which the first and second membranes of electrically conductive material are selected from the group consisting of gold, palladium, and indium tin oxide.

48. The panel of claim 43 in which the contrast enhancement medium is formed of a polymeric coating material.

49. The panel of claim 48 in which the contrast enhancement medium is selected from the group consisting of cellulose based resins, acrylics, vinyls, styrenes, epoxies, and combinations thereof.

50. The panel of claim 48 in which the contrast enhancement medium is a thermally cured mixture of acrylic copolymer resin, epoxy resin, and an alkyleneamine type hardener.

51. The panel of claim 43 in which the flexible plastic film placed on the outside of the antiglare layer is selected from the group consisting of polycarbonate and polyethylene terephthalate.

52. The panel of claim 43 further comprising:

(a) an adhesive layer adjacent to and located behind the first electrically conductive means; and

(b) a rigid backing means laminated to the first electrically conductive means by the adhesive layer.

53. The panel of claim 52 in which the rigid backing means is a plastic.

54. The panel of claim 53 in which the plastic is acrylic plastic.

55. The panel of claim 52 in which the adhesive layer is a pressure sensitive adhesive.

56. The panel of claim 52 in which the adhesive layer is a liquid adhesive.

57. The panel of claim 56 in which the liquid adhesive is one selected from the group consisting of polyurethanes, epoxy adhesives, acrylic adhesives, and vinyl adhesives.

58. A contrast enhancing substantially transparent touch panel adapted for use in a motor vehicle instrument panel comprising:

(a) a selectively addressable switch array having;

(i) a static element having a first plastic film of polyester terephthalate coated with an electrically conductive first membrane of indium tin oxide on its front surface;

(ii) a dynamic element having a flexible second plastic film of polyester terephthalate coated with a flexible electrically conductive second membrane of indium tin oxide on its back surface, the dynamic element being selectively displaceable so that the second conductive membrane can contact the first conductive membrane at selected points;

(iii) means for keeping the first and second membranes facing each other, spaced apart, parallel, and in close proximity;

(b) a layer of urethane adhesive adjacent to and located behind the first plastic film;

(c) a rigid backing means of acrylic plastic laminated to the first plastic film by the urethane adhesive layer;

(d) an antiglare layer located in front of the dynamic element, the antiglare layer having a contract enhancement medium whereby ambient light reflected from the conductive membranes is selectively attenuated by being forced to pass through the contrast enhancement medium at least twice;

(e) a layer of silicone adhesive in front of the antiglare layer and bonding the antiglare layer to the dynamic element; and

(f) a flexible and transparent front layer of protective material, said layer having a graphic overlay of hardcoated polycarbonate and being stain and abrasion resistant.

59. A method for assembling a contrast enhanced substantially transparent touch panel comprising the steps of:

(a) locating an electrically conductive first membrane on the front surface of a first plastic film by coating the front surface of the film with an electrically conductive material;

(b) locating an electrically conductive second membrane on the back surface of a second plastic film by coating the back surface of the film with electrically conductive material, the two conductive membranes being so patterned as to be able to form a selectively addressable switch array;

(c) placing an antiglare layer having a contrast enhancement medium between the front surface of the second plastic film and the back surface of a third plastic film, so that the contrast enhancement medium is located such that ambient light is selectively attenuated by being forced to pass through the contrast enhancement medium at least twice;

(d) holding the antiglare layer and the second and third plastic film firmly in place with a clear liquid adhesive capable of curing in situ to form a flexible solid layer, the adhesive being selected from the group consisting of silicone adhesives and polyurethane adhesives, so that there is no air gap between the second and third plastic films, a flexible first laminate being formed by placing the antiglare layer between the back surface of the third plastic film and the front surface of the second plastic film with the antiglare layer separated from the front surface of the second plastic film by the liquid adhesive, applying pressure to the laminate so that the antiglare layer is impregnated with the adhesive, and allowing the adhesive to cure;

(e) applying an abrasion and stain resistant coating onto the front surface of the third plastic film to form a flexible front protective layer; and

(f) forming a selectively addressable switch array by affixing the first and second plastic films to one another after the conductive membranes have been located thereon so that the second conductive membrane is facing, spaced apart from, parallel to, and in close proximity to the first conductive membrane, the second conductive membrane and structures attached thereto being selectively displaceable so that the second conductive membrane can contact the first conductive membrane at selected points on the first conductive membrane, whereby the switch array is flexibly responsive to tactile activation.

60. The method of claim 59 further comprising the steps of forming a second laminate by placing the back side of the touch panel and a rigid backing means on either side of a second adhesive layer, applying pressure to eliminate air, forcing the back side of the touch panel into intimate contact with the rigid backing means, and allowing the second adhesive layer to cure.