Electrophoretic display with in-plane switching

• US 20030035198A1
• Filed: 07/16/2002
• Published: 02/20/2003
• Est. Priority Date: 03/03/2000
• Status: Active Grant

• Current Assignee: David Chen, Jerry Chung, Rong-Chang Liang
• Original Assignee: SiPix Imaging, Inc. (E Ink Holdings Incorporated)
• Inventors: Liang, Rong-Chang, Chen, David, Chung, Jerry
• Granted Patent: US 6,885,495 B2
• Time in Patent Office: Days
• US Class Current: 359/296
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/1679 Gaskets; Spacers; Sealing of cells; Filling or closing of cells
• CPC Class Codes: G02F 2201/12 electrode

Abstract

The present invention relates to an improved EPD which comprises the in plane switching mode. More specifically, the EPD of the present invention comprises isolated cells formed from microcups of well defined size, shape and aspect ratio and the movement of the particles in the cells is controlled by the in-plane switching mode. The EPD of the present invention may be produced in a continuous manufacturing process, and the display gives improved color saturation.

Claims

1. An electrophoretic display comprising isolated electrophoretic cells formed from microcups of well-defined size, shape and aspect ratio with an in-plane switching mode.

2. The electrophoretic display of claim 1 having two in-plane electrodes.

3. The electrophoretic display of claim 1 having one in-plane electrode.

4. The electrophoretic display of claim 1 wherein the microcups have a top opening ranging from about 10² to about 1×

10⁶ μ

m².

5. The electrophoretic display of claim 4 wherein the microcups have a top opening ranging from about 10³ to about 1×

10⁵ μ

m².

6. The electrophoretic display of claim 1 wherein the depth of the microcups is in the range of about 5 to about 200 microns.

7. The electrophoretic display of claim 6 wherein the depth of the microcups is in the range of about 20 to about 100 microns.

8. The electrophoretic display of claim 1 wherein the opening to the total area ratio is in the range of from about 0.2 to about 0.95.

9. An electrophoretic display having isolated cells formed from microcups of well-defined size, shape and aspect ratio, said cells comprising

a transparent viewing layer on one side of the display;

a layer having in-plane electrodes on the opposite side of the display;

and said cells are filled with a dielectric solvent or solvent mixture having charged particles dispersed therein.

10. The electrophoretic display of claim 9 further comprising a separate background layer.

11. The electrophoretic display of claim 9 wherein said transparent viewing layer is colorless.

12. The electrophoretic display of claim 11 wherein said separate background layer is on top of the layer having in-plane electrodes.

13. The electrophoretic display of claim 11 wherein said separate background layer is underneath the layer having in-plane electrodes.

14. The electrophoretic display of claim 11 wherein said layer having in-plane electrodes serves as the background layer and the in-plane electrodes may be white or colored.

15. The electrophoretic display of claim 9 wherein the display is a monochrome display.

16. The electrophoretic display of claim 15 wherein said dielectric solvent is clear and colorless.

17. The electrophoretic display of claim 16 wherein all said cells have particles of the white color and the same background color.

18. The electrophoretic display of claim 17 wherein said background color is black, red, green, blue, yellow, cyan or magenta.

19. The electrophoretic display of claim 16 wherein all said cells have particles of the same color and the white background color.

20. The electrophoretic display of claim 19 wherein said particles are black, red, green, blue, yellow, cyan or magenta.

21. The electrophoretic display of claim 16 wherein said individual cells have particles of mixed colors and the same background color.

22. The electrophoretic display of claim 21 wherein the mixed colors are two or more colors selected from a group consisting of black, white, red, green, blue, yellow, cyan and magenta.

23. The electrophoretic display of claim 22 wherein said background color is selected from a group consisting of black, white, red, green, blue, yellow, cyan and magenta.

24. The electrophoretic display of claim 9 wherein said display is a multiple color display.

25. The electrophoretic display of claim 24 wherein said cells have particles of the white color and different background colors.

26. The electrophoretic display of claim 24 wherein said cells have particles of the black color and different background colors.

27. The electrophoretic display of claim 24 wherein said cells have particles of different colors and a white background.

28. The electrophoretic display of claim 24 wherein said cells have particles of different colors and a black background.

29. The electrophoretic display of claim 9 wherein said transparent viewing layer is colored or by adding a color filter.

30. The electrophoretic display of claim 29 wherein said separate background layer is on top of the layer having in-plane electrodes.

31. The electrophoretic display of claim 29 wherein said separate background layer is underneath the layer having in-plane electrodes.

32. The electrophoretic display of claim 29 wherein said layer having in-plane electrodes serves as the background layer and the in-plane electrodes may be white or colored.

33. The electrophoretic display of claim 29 wherein all said cells have white particles and black background.

34. The electrophoretic display of claim 33 wherein all said cells have the transparent viewing layer of the same color.

35. The electrophoretic display of claim 33 wherein said cells have the transparent viewing layers of different colors.

58. The electrophoretic display of claim 9 wherein a substrate containing an array of thin film transistors is used as the layer of in-plane electrodes.

36. A process for the manufacture of an electrophoretic display having isolated cells formed from microcups having well defined size, shape and aspect ratio, said process comprises

a) forming a layer by coating a radiation curable material over a transparent insulator substrate;

b) forming microcups on the radiation curable material by microembossing or imagewise exposure to radiation;

c) filling the microcups with an electrophoretic composition;

d) sealing the microcups;

e) laminating the sealed microcups with a substrate containing in-plane electrodes.

37. The process for the manufacture of an electrophoretic display of claim 36 with substrate containing in-plane electrodes and an adhesive.

40. The process of claim 36 wherein the microcups have a top opening ranging from about 10² to about 1×

10⁶ μ

m².

42. The process of claim 36 wherein said transparent insulator substrate is colorless.

43. The process of claim 42 wherein all said cells have the same background color and are filled with an electrophoretic composition comprising charged particles of the same color dispersed in a clear colorless dielectric solvent.

44. The process of claim 42 wherein said cells have different background colors and are filled with an electrophoretic composition comprising charged particles of the same color dispersed in a clear colorless dielectric solvent.

45. The process of claim 42 wherein said cells have the same background color and are filled with an electrophoretic composition comprising charged particles of the different colors dispersed in a clear colorless dielectric solvent.

50. The process of claim 36 wherein said transparent insulator substrate is colored.

51. The process of claim 50 wherein said cells have the black background and are filled with an electrophoretic composition comprising charged white particles dispersed in a clear colorless dielectric solvent.

52. The process of claim 51 wherein all cells have the transparent insulator substrate of the same color.

53. The process of claim 51 wherein said cells have the transparent insulator substrate of different colors.

38. A process for the manufacture of an electrophoretic display having isolated cells formed from microcups having well defined size, shape and aspect ratio, said process comprises

a) forming a layer by coating a radiation curable material over a substrate containing in-plane electrodes;

b) forming microcups on the radiation curable material by microembossing or imagewise exposure to radiation;

c) filling the microcups with an electrophoretic composition;

d) sealing the microcups;

e) laminating the sealed microcups with a transparent insulator substrate.

39. The process for the manufacture of an electrophoretic display of claim 38 with a transparent insulator substrate and an adhesive.

41. The process of claim 38 wherein the microcups have a top opening ranging from about 10² to about 1×

10⁶ μ

m².

46. The process of claim 38 wherein said transparent insulator substrate is colorless.

47. The process of claim 46 wherein all said cells have the same background color and are filled with an electrophoretic composition comprising charged particles of the same color dispersed in a clear colorless dielectric solvent.

48. The process of claim 46 wherein said cells have different background colors and are filled with an electrophoretic composition comprising charged particles of the same color dispersed in a clear colorless dielectric solvent.

49. The process of claim 46 wherein said cells have the same background color and are filled with an electrophoretic composition comprising charged particles of different colors dispersed in a clear colorless dielectric solvent.

54. The process of claim 38 wherein said transparent insulator substrate is colored.

55. The process of claim 54 wherein said cells have the black background and are filled with an electrophoretic composition comprising charged white particles dispersed in a clear colorless dielectric solvent.

56. The process of claim 55 wherein all cells have the transparent insulator substrate of the same color.

57. The process of claim 55 wherein said cells have the transparent insulator substrate of different colors.