Electrophoretic display comprising optical biasing element

• US 20030011560A1
• Filed: 05/10/2002
• Published: 01/16/2003
• Est. Priority Date: 08/27/1998
• Status: Active Grant

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: E Ink Holdings Incorporated
• Inventors: Albert, Jonathan D., Comiskey, Barrett
• Granted Patent: US 7,256,766 B2
• Time in Patent Office: Days
• US Class Current: 345/107
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/16757 Microcapsules
• CPC Class Codes: G02F 1/1677 Structural association of cells with optical devices, e.g. reflectors or illuminating devices

Abstract

The invention features an electrophoretic display element. The display element includes an electrophoretic display medium, an optical biasing element to modify an optical characteristic of the electrophoretic display element, and an addressing electrode to address the electrophoretic display medium. The optical biasing element may include, for example, a distinct layer of material, or may include particles or molecules embedded in a layer of the display element.

Claims

1. An electrophoretic display element comprising:

an electrophoretic display medium;

an optical biasing element to modify an optical characteristic of the electrophoretic display element; and

an addressing electrode to address the electrophoretic display medium.

2. The electrophoretic display element of claim 1 wherein the optical biasing element is disposed between the addressing electrode and the electrophoretic display medium.

3. The electrophoretic display element of claim 1 wherein the addressing electrode is disposed between the electrophoretic display medium and the optical biasing element.

4. The electrophoretic display element of claim 1 wherein the electrophoretic display medium is disposed between the optical biasing element and the addressing electrode.

5. The electrophoretic display element of claim 1 wherein the optical biasing element is selected with a predetermined optical characteristic.

6. The electrophoretic display element of claim 5 wherein the predetermined optical characteristic is an absorption characteristic that is selected to cooperate with an optical characteristic of the electrophoretic display medium to control the optical characteristic of the electrophoretic display element.

7. The electrophoretic display element of claim 5 wherein the predetermined optical characteristic is a reflectance characteristic that is selected to cooperate with an optical characteristic of the electrophoretic display medium to control the optical characteristic of the electrophoretic display element.

8. The electrophoretic display element of claim 5 wherein the predetermined optical characteristic of the optical biasing element is substantially similar to an optical characteristic of the electrophoretic display medium.

9. The electrophoretic display element of claim 1 wherein the addressing electrode comprises a polymer and a conductive species that imparts a conductive property to the addressing electrode.

10. The electrophoretic display element of claim 1 wherein

(i) the optical biasing element comprises a polymer and a colored species that imparts an optical bias effect to the optical biasing element;

and

(ii) the addressing electrode comprises a polymer and a conductive species that imparts a conductive property to the addressing electrode.

11. The electrophoretic display element of claim 1 wherein the electrophoretic display medium comprises an electrophoretic fluid and a binder, and wherein the optical biasing element is embedded in the binder.

12. The display element of claim 11 wherein the electrophoretic display medium further comprises at least one capsule that encapsulates the electrophoretic fluid, and the at least one capsule is surrounded at least in part by the binder.

13. The display element of claim 11 wherein the binder defines at least one void that encapsulates the electrophoretic fluid.

14. The electrophoretic display element of claim 1 wherein the optical biasing element is embedded in the addressing electrode.

15. The electrophoretic display element of claim 1 wherein the optical biasing element comprises a lamination adhesive.

16. The electrophoretic display element of claim 1 wherein the optical biasing element comprises a polymer and a colored species that imparts an optical bias effect to the optical biasing element.

17. The electrophoretic display element of claim 16 wherein the optical biasing element comprises carbon black particles.

18. The electrophoretic display element of claim 16 wherein the optical biasing element comprises a noble metal.

19. The electrophoretic display element of claim 16 wherein the optical biasing element comprises titania particles.

20. The electrophoretic display element of claim 1 wherein the addressing electrode comprises a polymer and a conductive species that imparts a conductive property.

21. The electrophoretic display element of claim 1 wherein the optical biasing element comprises a polymeric carrier and a biasing material compounded with the polymeric carrier.

22. The electrophoretic display element of claim 1 wherein the optical biasing element is in contact with the addressing electrode.

24. The method of claim 23 further comprising laminating the electrophoretic display medium, the optical biasing element and the addressing electrode.

25. The method of claim 24 wherein providing the optical biasing element comprises providing an adhesive layer, and laminating comprises disposing the optical biasing element between the electrophoretic display medium and the addressing electrode.

26. The method of claim 23 further comprising selecting a reflectance of the optical biasing element.

27. The method of claim 23 further comprising selecting a color of the optical biasing element.

30. The method of claim 29 wherein steps (B) and (C) comprise forming the addressing electrode and the optical biasing element from metallic particles.

31. The method of claim 29 wherein providing an addressing electrode comprises providing a polymeric carrier, and embedding comprises compounding carbon into the polymeric carrier.

32. The method of claim 29 wherein embedding comprises compounding a pigment material with an addressing electrode material.

23. A method for constructing an electrophoretic display element comprising:

(A) providing an electrophoretic display medium;

(B) providing an addressing electrode adjacent to the electrophoretic display medium; and

(C) providing an optical biasing element adjacent to the electrophoretic display medium, the optical biasing element modifying an optical characteristic of the electrophoretic display element.

28. A method for constructing an electrophoretic display element comprising:

(A) providing an electrophoretic display medium comprising a binder and an electrophoretic fluid;

(B) embedding an optical biasing element in the binder to modify an optical characteristic of the electrophoretic display element; and

(C) providing an addressing electrode adjacent to the electrophoretic display medium.

29. A method for constructing an electrophoretic display element comprising:

(A) providing an electrophoretic display medium;

(B) providing an addressing electrode adjacent to the electrophoretic display medium; and

(C) embedding an optical biasing element in the addressing electrode to modify an optical characteristic of the electrophoretic display element.