Touchscreen with one carbon nanotube conductive layer

• US 7,535,462 B2
• Filed: 06/02/2005
• Issued: 05/19/2009
• Est. Priority Date: 06/02/2005
• Status: Expired due to Fees

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Majumdar, Debasis, Spath, Todd M., Anderson, Charles C., Irvin, Glen C. Jr.
• Primary Examiner(s): Hjerpe; Richard
• Assistant Examiner(s): Sheng; Tom V
• Application Number:
  US11/143,539
• Publication Number:
  US 20060274047A1
• Time in Patent Office: 1,447 Days
• Field of Search: 345/173, 345/174, 428/1.4, 428/297.4, 428/411.1, 977/734, 977/742
• US Class Current: 345/174
• 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: Y10S 977/742 Carbon nanotubes, CNTs
• CPC Class Codes: Y10T 428/24994 Fiber embedded in or on the surface of a polymeric matrix

Abstract

The present invention is directed to a touchscreen comprising touch side electrode and device side electrode wherein each electrode comprises an insulating substrate and an exposed electrically conductive layer, wherein said exposed electrically conductive layers are adjacent and separated by dielectric spacers, and wherein only one of the exposed electrically conductive layers comprises carbon nanotubes.

Claims

1. A touchscreen comprising touch side electrode and device side electrode wherein each electrode comprises an insulating substrate and an exposed electrically conductive layer, wherein said exposed electrically conductive layers are adjacent and separated by dielectric spacers, wherein only one of the exposed electrically conductive layers comprises carbon nanotubes wherein said carbon nanotubes comprise single-wall carbon nanotubes and wherein said carbon nanotubes comprise covalently attached hydrophilic species.

2. The touchscreen of claim 1 wherein at least one of said electrodes comprises an electrically conductive layer comprising at least one material selected from the group consisting of electronically conductive polymers, transparent conducting oxides and transparent metal films.

3. The touchscreen of claim 2 wherein said electrically conductive layer comprises a mixture of a cationic polyethylenedioxythiophene and polyanion.

4. The touchscreen of claim 3 wherein said mixture of a cationic polyethylenedioxythiophene and polyanion has a figure of merit of less than 50.

5. The touchscreen of claim 2 wherein said electrically conductive layer comprises polypyrrole, polyaniline or polythiophene.

6. The touchscreen of claim 2 wherein said electrically conductive layer not comoprising carbon nanotubes comprises tin doped indium oxide, fluorine doped zinc oxide, aluminum doped zinc oxide, indium doped zinc oxide, antimony doped tin oxide, or fluorine doped tin oxide.

7. The touchscreen of claim 2 wherein said electrically conductive layer comprises a transparent metal film comprising silver, gold, copper, palladium, platinum or alloys of these materials.

8. The touchscreen of claim 2 wherein said electronically conductive polymer comprises a binder.

9. The touchscreen of claim 8 wherein said binder comprises polyvinylalcohol, polyvinylbutyral, polyacrylates, polyurethanes or epoxies.

10. The touchscreen of claim 1 wherein the hydrophilic species is present in an amount of between 0.5 and 5 atomic % of the single-wall carbon nanotubes.

11. The touchscreen of claim 1 wherein said hydrophilic species is selected from the group consisting of carboxylic acid, carboxylic acid salt mixtures thereof.

12. The touchscreen of claim 1 wherein said hydrophilic species comprises a sulfur containing group selected from:

SO_xZ_y

Wherein x may range from 1-3 and Z may be a Hydrogen atom or a metal cation selected from the metals Na, Mg, K, Ca, Zn, Mn, Ag, Au, Pd, Pt, Fe, Co and y may range from 0 or 1.

13. The touchscreen of claim 8 wherein said carbon nanotubes have an outer diameter of between 0.5 and 5 nanometers.

14. The touchscreen of claim 1 wherein said carbon nanotubes comprise bundles of a diameter of between 1 and 50 nanometers.

15. The touchscreen of claim 1 wherein said carbon nanotubes comprise bundles of a diameter of between 1 and 20 nanometers.

16. The touchscreen of claim 1 wherein said carbon nanotubes have a length of between 20 nanometers and 50 microns.

17. The touchscreen of claim 1 wherein said carbon nanotubes comprise bundles of a length of between 20 nanometers and 50 microns.

18. The touchscreen of claim 1 wherein said carbon nanotubes are metallic carbon nanotubes.

19. The touchscreen of claim 1 wherein said hydrophilic species comprises sulfonic acids or sulfonic acid salts or mixtures thereof.

20. The touchscreen of claim 1 wherein said carbon nanotubes are open end carbon nanotubes.

21. The touchscreen of claim 1 wherein said covalently attached hydrophilic species is present on the outside wall of said carbon nanotube.

22. The touchscreen of claim 1 wherein the electronically conductive layer comprising carbon nanotubes further comprises a binder.

23. The touchscreen of claim 1 wherein at least one of said electrodes further comprises an electronically conductive layer adjacent the substrate having a sheet resistance of between 10 and 10,000 Ohm per square.

24. The touchscreen of claim 1 wherein said electronically conductive layer comprising carbon nanotubes have a sheet resistance of between 10² to 10⁶ Ohm per square.

25. The touchscreen of claim 1 wherein said screen is capable of greater than 500,000 single point actuations.

26. The touchscreen of claim 1 wherein said touchscreen has a visible light transparency of greater than 70 percent.

27. The touchscreen of claim 1 wherein said substrates have a visible light transparency of greater than 70 percent and comprise polyethyleneterephthalate, polyethylenenaphthalate, polycarbonate or glass.

28. The touchscreen of claim 1 wherein said touch side substrate further comprises an anti-glare coat.

29. The touchscreen of claim 1 wherein said touch side substrate further comprises an anti-reflection coat.

30. The touchscreen of claim 1 wherein said touch side substrate further comprises a hard coat having a pencil hardness greater than 2H.

31. The touchscreen of claim 1 wherein said touch side substrate further comprises a ultra violet light absorbing layer.

32. The touchscreen of claim 1 wherein the force required to actuate a point on the touchscreen does not change by more than 50 percent over 500,000 single point actuations.

33. The touchscreen of claim 1 wherein said the exposed layer comprising carbon nanotubes further comprises electrically conductive polymer, metal particles, or transparent conducting oxide particles.

34. The touchscreen of claim 1 wherein the electrode that does not comprise carbon nanotubes comprises a mixture of electrically conductive polymer, metal particles, or transparent conducting oxide particles.

35. The touchscreen of claim 1 wherein said exposed layer comprising carbon nanotubes is on the touch side of said touchscreen.

36. A device comprising a display device having attached thereto a touchscreen comprising touch side electrode and device side electrode wherein each electrode comprises an insulating substrate and an exposed electrically conductive layer, wherein said exposed electrically conductive layers are adjacent and separated by dielectric spacers, wherein only one of the exposed electrically conductive layers comprises carbon nanotubes wherein said carbon nanotubes comprise single-wall carbon nanotubes, and wherein said carbon nanotubes comprise covalently attached hydrophilic species.

37. The device of claim 36 wherein said display device comprises a LCD based display.

38. The device of claim 37 wherein said LCD comprises a polarizer plate and the touchscreen is adhesively attached to said polarizer plate.

39. The device of claim 36 wherein the exposed layer comprising carbon nanotubes is on the touch side of said touchscreen.