Electro-optic display and materials for use therein
View Patent ↗A polyurethane is formed from an isocyanate and a polyester diol having a molecular weight less than about 2000, or a polyester diol comprising two polyester diol segments connected by a steric hindrance group, each of the polyester diol segments having a molecular weight less than about 2000. The polyurethane is useful as a binder in electro-optic displays, and in components used to form such displays.
1. A polyurethane formed from an isocyanate and a polyester diol having a molecular weight less than about 2000, or a polyester diol comprising two polyester diol segments connected by a steric hindrance group, each of the polyester diol segments having a molecular weight less than about 2000.
2. A polyurethane according to claim 1 formed from polycaprolactone diol having a molecular weight less than about 1500.
3. A polyurethane according to claim 2 wherein the polycaprolactone diol comprises two polycaprolactone segments connected by a bending group, each of the polycaprolactone segments having a molecular weight not greater than about 1500.
4. A polyurethane according to claim 3 wherein the steric hindrance group comprises a quaternary carbon atom.
5. A polyurethane according to claim 4 wherein the steric hindrance group comprises a —C(CH 3 ) 2 — grouping.
6. A polyurethane according to claim 1 in the form of an aqueous latex.
7. A polyurethane formed from an isocyanate and a polyester diol, the polyurethane not crystallizing between about −10° C. and about 70° C. when coated as a thin film.
8. A polyurethane according to claim 7 in the form of an aqueous latex.
9. An electro-optic display comprising a layer of a solid electro-optic material, and at least one electrode arranged to apply an electric field to the layer of electro-optic material, the layer of electro-optic material comprising a binder, wherein the binder comprises a polyurethane according to claim 1 .
10. An electronic book reader, portable computer, tablet computer, cellular telephone, smart card, sign, watch, shelf label or flash drive comprising a display according to claim 9 .
11. An electro-optic display comprising a layer of a solid electro-optic material, and at least one electrode arranged to apply an electric field to the layer of electro-optic material, the layer of electro-optic material comprising a binder, wherein the binder comprises a polyurethane according to claim 7 .
12. An electronic book reader, portable computer, tablet computer, cellular telephone, smart card, sign, watch, shelf label or flash drive comprising a display according to claim 11 .
13. An article of manufacture comprising in order:
a light-transmissive electrically-conductive layer;
a layer of a solid electro-optic medium comprising a binder and in electrical contact with the electrically-conductive layer;
an adhesive layer; and
a release sheet,
wherein the binder comprises a polyurethane according to claim 1 .
14. An article of manufacture comprising in order:
a light-transmissive electrically-conductive layer;
a layer of a solid electro-optic medium comprising a binder and in electrical contact with the electrically-conductive layer;
an adhesive layer; and
a release sheet,
wherein the binder comprises a polyurethane according to claim 7 .
15. An article of manufacture comprising:
a layer of a solid electro-optic medium comprising a binder and having first and second surfaces on opposed sides thereof;
a first adhesive layer on the first surface of the layer of electro-optic medium;
a release sheet disposed on the opposed side of the first adhesive layer from the layer of electro-optic medium; and
a second adhesive layer on the second surface of the layer of electro-optic medium,
wherein the binder comprises a polyurethane according to claim 1 .
16. An article of manufacture comprising:
a layer of solid electro-optic medium comprising a binder and having first and second surfaces on opposed sides thereof,
a first adhesive layer on the first surface of the layer of electro-optic medium;
a release sheet disposed on the opposed side of the first adhesive layer from the layer of electro-optic medium; and
a second adhesive layer on the second surface of the layer of electro-optic medium,
wherein the binder comprises a polyurethane according to claim 7 .
17. An article of manufacture for use in forming an electro-optic display, the article of manufacture comprising, in order:
at least one of a light-transmissive protective layer and a light-transmissive electrically-conductive layer;
an adhesive layer;
a layer of a solid electro-optic medium comprising a binder; and
a release sheet,
wherein the binder comprises a polyurethane according to claim 1 .
18. An article of manufacture for use in forming an electro-optic display, the article of manufacture comprising, in order:
at least one of a light-transmissive protective layer and a light-transmissive electrically-conductive layer;
an adhesive layer;
a layer of a solid electro-optic medium comprising a binder; and
a release sheet,
wherein the binder comprises a polyurethane according to claim 7 .
19. An article of manufacture for use in forming an electro-optic display, the article of manufacture comprising:
a layer of a solid electro-optic medium comprising a binder and having first and second surfaces on opposed sides thereof;
a first release sheet covering the first surface of the layer of solid electro-optic medium; and
a second release sheet covering the second surface of the layer of solid electro-optic medium,
wherein the binder comprises a polyurethane according to claim 1 .
20. An article of manufacture for use in forming an electro-optic display, the article of manufacture comprising:
a layer of a solid electro-optic medium comprising a binder and having first and second surfaces on opposed sides thereof;
a first release sheet covering the first surface of the layer of solid electro-optic medium; and
a second release sheet covering the second surface of the layer of solid electro-optic medium,
wherein the binder comprises a polyurethane according to claim 7 .
21. An article of manufacture for use in forming an electro-optic display, the article of manufacture comprising, in order:
a first release sheet;
a layer of a solid electro-optic medium comprising a binder;
an adhesive layer; and
a second release sheet,
wherein the binder comprises a polyurethane according to claim 1 .
22. An article of manufacture for use in forming an electro-optic display, the article of manufacture comprising, in order:
a first release sheet;
a layer of a solid electro-optic medium comprising a binder;
an adhesive layer; and
a second release sheet,
wherein the binder comprises a polyurethane according to claim 7 .