Touchscreen with carbon nanotube conductive layers
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.
1. A touchscreen comprising touch side and device side electrodes wherein each electrode comprises in order an insulating substrate, an exposed electrically conductive layer, wherein said exposed electrically conductive layers are adjacent and separated by dielectric spacers, and wherein said exposed electrically conductive layers comprise single wall carbon nanotubes and wherein said carbon nanotubes comprise covalently attached hydrophilic species.
2. The touchscreen of claim 1 wherein the hydrophilic species is present in an amount of between 0.5 and 5 atomic %.
3. The touchscreen of claim 1 wherein said hydrophilic species comprises carboxylic acid or carboxylic acid salt or mixtures thereof.
4. The touchscreen of claim 1 wherein said hydrophilic species comprises a sulfur containing group selected from:
SO x Z y
Wherein x ranges from 1-3 and Z may be a Hydrogen atom or a metal cation of such metals as Na, Mg, K, Ca, Zn, Mn, Ag, Au, Pd, Pt, Fe, Co and y may range from 0 or 1.
5. The touchscreen of claim 1 wherein said carbon nanotubes have an outer diameter of between 0.5 and 5 nanometers.
6. The touchscreen of claim 1 wherein said carbon nanotubes comprise bundles of a diameter of between 1 and 50 nanometers.
7. The touchscreen of claim 1 wherein said carbon nanotubes comprise bundles of a diameter of between 1 and 20 nanometers.
8. The touchscreen of claim 1 wherein said carbon nanotubes have a length of between 20 nanometers and 50 microns.
9. The touchscreen of claim 1 wherein said carbon nanotubes comprise bundles of a length of between 20 nanometers and 50 microns.
10. The touchscreen of claim 1 wherein said carbon nanotubes are metallic carbon nanotubes.
11. The touchscreen of claim 1 wherein said hydrophilic species comprises sulfonic acids or sulfonic acid salts or mixtures thereof.
12. The touchscreen of claim 1 wherein said carbon nanotubes are open end carbon nanotubes.
13. The touchscreen of claim 1 wherein said covalently attached hydrophilic species is present on the outside wall of said carbon nanotube.
14. The touchscreen of claim 1 wherein the electronically conductive layer comprising carbon nanotubes further comprises a binder.
15. The touchscreen of claim 1 wherein said electronically conductive layer adjacent said substrate has a sheet resistance of between 10 and 10 6 Ohm per square.
16. The touchscreen of claim 1 wherein said electronically conductive layer comprising carbon nanotubes have a sheet resistance of between 10 2 to 10 4 Ohm per square.
17. The touchscreen of claim 1 wherein said electronically conductive layer comprises a binder.
18. The touchscreen of claim 17 wherein said binder comprises water soluble or water dispersible polymers.
19. The touchscreen of claim 1 wherein said touchscreen is capable of greater than 500,000 single point actuations.
20. A touchscreen comprising touch side and device side electrodes wherein each electrode comprises in order an insulating substrate, an exposed electrically conductive layer, wherein said exposed electrically conductive layers are adjacent and separated by dielectric spacers, and wherein said exposed electrically conductive layers comprise single wall carbon nanotubes and wherein said carbon nanotubes comprise covalently attached hydrophilic species; and
wherein said touchscreen has a visible light transparency of greater than 70 percent.
21. 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.
22. The touchscreen of claim 1 wherein said touch side substrate further comprises an anti-glare coat.
23. The touchscreen of claim 1 wherein said touch side substrate further comprises an anti-reflection coat.
24. The touchscreen of claim 1 wherein said touch side substrate further comprises a hardcoat having a pencil hardness greater than 2H.
25. The touchscreen of claim 1 wherein said touch side substrate further comprises a ultra violet light absorbing layer.
26. A touchscreen comprising touch side and device side electrodes wherein each electrode comprises in order an insulating substrate, an exposed electrically conductive layer, wherein said exposed electrically conductive layers are adjacent and separated by dielectric spacers, and wherein said exposed electrically conductive layers comprise single wall carbon nanotubes and wherein said carbon nanotubes comprise covalently attached hydrophilic species;
wherein said touchscreen has a visible light transparency of greater than 70 percent; and
wherein the average force required to actuate a point on the touchscreen does not change by more than 100 percent over 500,000 single point actuations.
27. A device comprising a display device having attached thereto a touchscreen comprising touch side and device side electrodes wherein each electrode comprises an exposed electrically conductive layer, wherein said exposed electrically conductive layers are adjacent and separated by dielectric spacers, and wherein at least the first electrically conductive layers or the exposed electrically conductive layers comprise carbon nanotubes and wherein said carbon nanotubes comprise covalently attached hydrophilic species; and
wherein said touchscreen has a visible light transparency of greater than 70 percent.
28. The device of claim 27 wherein said display device comprises a LCD based display.
29. The device of claim 28 wherein said LCD comprises a polarizer plate and the touchscreen is adhesively attached to said polarizer plate.
30. A touchscreen comprising touch side and device side electrodes wherein each electrode comprises in order an insulating substrate, an exposed electrically conductive layer, wherein said exposed electrically conductive layers are adjacent and separated by dielectric spacers, and wherein said exposed electrically conductive layers comprise single wall carbon nanotubes and wherein said carbon nanotubes comprise covalently attached hydrophilic species; and
wherein the average force required to actuate a point on the touchscreen does not change by more than 50 percent over 500,000 single point actuations.
31. The touchscreen of claim 27 wherein the average force required to actuate a point on the touchscreen does not change by more than 100 percent over 500,000 single point actuations.