Electro-optic displays, and materials for use therein

• US 7,672,040 B2
• Filed: 04/04/2007
• Issued: 03/02/2010
• Est. Priority Date: 11/05/2003
• Status: Active Grant

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: E Ink Holdings Incorporated
• Inventors: Patry, Shamus Ford, Sohn, Seungman, Whitesides, Thomas H.
• Primary Examiner(s): Spector; David N
• Application Number:
  US11/696,560
• Publication Number:
  US 20070247697A1
• Time in Patent Office: 1,063 Days
• Field of Search: 156/215, 156/272.2, 156/273.9, 156/275.7, 156/325, 359/245, 359/315, 359/321
• US Class Current: 359/321
• CPC Class Codes: G02F 1/133305 Flexible substrates, e.g. plastics, organic film
• CPC Class Codes: G02F 1/1681 having two or more microcells partitioned by walls, e.g. of microcup type
• CPC Class Codes: G02F 2202/28 Adhesive materials or arrangements

Abstract

A flexible electro-optic display comprises a layer of solid electro-optic material; a backplane comprising at least one electrode arranged to apply an electric field to the layer of electro-optic material; and an adhesive layer disposed between the layer of electro-optic material and the backplane and adhesively securing the layer of electro-optic material to the backplane, the adhesive layer having a storage modulus (G′) of at least about 10⁴ Pascals at 10⁻³ Hz and 70° C.

Claims

1. A flexible electro-optic display comprising:

a layer of solid electro-optic material capable of changing at least one optical characteristic upon application of an electric field thereto;

a backplane comprising at least one electrode arranged to apply an electric field to the layer of electro-optic material; and

an adhesive layer disposed between the layer of electro-optic material and the backplane and adhesively securing the layer of electro-optic material to the backplane,

the adhesive layer having a storage modulus (G′

) of at least about 10⁴ Pascals at 10<sup>−

3</sup> Hz and 70°

C.

2. An electro-optic display according to claim 1 wherein the backplane comprises a polymeric film having a thickness not greater than about 300 μ

m, the display further comprising a front plane lying on the opposed side of the electro-optic material from the backplane and comprising a polymeric film having a thickness not greater than about 300 μ

m.

3. A display according to claim 2 wherein the backplane and front plane each comprise a polymeric film having a thickness not greater than about 100 μ

m.

4. A display according to claim 1 wherein the backplane comprises a plurality of non-linear electronic devices comprising conductive polymers.

5. A display according to claim 1 wherein the adhesive layer has a storage modulus (G′

) of at least about 3×

10⁴ Pascals at 10<sup>−

3</sup> Hz and 70°

C.

6. A display according to claim 5 wherein the adhesive layer has a storage modulus (G′

) of at least about 6×

10⁴ Pascals at 10<sup>−

3</sup> Hz and 70°

C.

7. A display according to claim 1 having a second layer of adhesive material disposed on the opposed side of the electro-optic material from the backplane, the second layer of adhesive having a storage modulus (G′

) of at least about 10⁴ Pascals at 10<sup>−

3</sup> Hz and 70°

C.

8. A display according to claim 1 wherein the adhesive layer comprises a polyurethane.

9. A display according to claim 1 wherein the adhesive layer comprises a cross-linked polymer.

10. A display according to claim 1 wherein the adhesive layer has been cross-linked with a thermally-activated cross-linking agent.

11. A display according to claim 10 wherein the adhesive layer has been cross-linked with a thermally-activated cross-linking agent containing an epoxy group.

12. A display according to claim 10 wherein the adhesive layer has been cross-linked with N,N-diglycidylaniline.

13. A display according to claim 9 wherein the adhesive layer has been cross-linked with an ultra-violet activated cross-linking agent.

14. A process for producing a flexible electro-optic display, the process comprising:

providing an assembly comprising a layer of solid electro-optic material capable of changing at least one optical characteristic upon application of an electric field thereto;

a flexible backplane comprising at least one electrode arranged to apply an electric field to the layer of electro-optic material; and

an adhesive layer disposed between the layer of electro-optic material and the backplane and adhesively securing the layer of electro-optic material to the backplane, the adhesive layer comprising a cross-linking agent capable of cross-linking the adhesive layer, and

exposing the adhesive layer to conditions effective to activate the cross-linking agent, thereby cross-linking the adhesive layer to produce an adhesive layer having a storage modulus (G′

) of at least about 10⁴ Pascals at 10<sup>−

3</sup> Hz and 70°

C.

15. A process according to claim 14 wherein the adhesive layer produced by cross-linking has a storage modulus (G′

) of at least about 3×

10⁴ Pascals at 10<sup>−

3</sup> Hz and 70°

C.

16. A process according to claim 15 wherein the adhesive layer produced by cross-linking has a storage modulus (G′

) of at least about 6×

10⁴ Pascals at 10<sup>−

3</sup> Hz and 70°

C.

17. A process according to claim 14 wherein the adhesive layer comprises a polyurethane.

18. A process according to claim 14 wherein the adhesive layer is cross-linked with a thermally-activated cross-linking agent.

19. A process according to claim 18 wherein the adhesive layer is cross-linked with a thermally-activated cross-linking agent containing an epoxy group.

20. A process according to claim 19 wherein the adhesive layer is cross-linked with N,N-diglycidylaniline.