Electrophoretic display and novel process for its manufacture

• US 6,829,078 B2
• Filed: 02/21/2003
• Issued: 12/07/2004
• Est. Priority Date: 03/03/2000
• Status: Expired due to Term

• Current Assignee: E Ink California, LLC (E Ink Corporation)
• Original Assignee: SiPix Imaging, Inc. (E Ink Holdings Incorporated)
• Inventors: Liang, Rong-Chang, Wang, Xiaojia, Chung, Jerry, Zang, Hongmei
• Primary Examiner(s): Dang, Hung Xuan
• Assistant Examiner(s): TRA, TUYEN Q
• Application Number:
  US10/372,027
• Publication Number:
  US 20040165252A1
• Time in Patent Office: 655 Days
• Field of Search: 359/296, 345/107, 345/105, 430/32, 430/34, 430/38, 204/450, 204/600, 505/472, 546/257
• US Class Current: 359/296
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/1677 Structural association of cells with optical devices, e.g. reflectors or illuminating devices
• CPC Class Codes: G02F 1/1679 Gaskets; Spacers; Sealing of cells; Filling or closing of cells

Abstract

This application is directed to electrophoretic displays and semi-finished display panels comprising display cells prepared from the microcup and top-sealing technologies.

Claims

1. An array of microcups each of said microcups comprises

a) opaque partition walls;

b) an electrophoretic composition filled therein; and

c) a polymeric sealing layer which is formed from a sealing composition having a specific gravity lower than that of the electrophoretic composition and sealingly adheres to the partition walls to enclose the electrophoretic composition within each microcup.

2. The array of microcups of claim 1 wherein said opaque partition walls are white.

3. The array of microcups of claim 1 wherein said opaque partition walls are gray.

4. The array of microcups of claim 1 wherein said opaque partition walls are formed from a composition comprising a UV curable material and a filler, dye, pigment or air pocket.

5. The array of microcups of claim 4 wherein said filler is selected from a group consisting of silica, ZnO, TiO₂, BaSO₄, CaCO₃ and polymer particles.

6. The array of microcups of claim 4 wherein said filler material is silica or polymer particles.

7. The array of microcups of claim 4 wherein said filler material is in the amount of 1-20% by weight of the composition.

8. The array of microcups of claim 7 wherein said filler material is in the amount of 2-10% by weight of the composition.

9. The array of microcups of claim 1 wherein said opaque partition walls are formed from a composition comprising a radiation curable material and a latent light scattering material.

10. The array of microcups of claim 9 wherein said latent light scattering material is a material that is compatible with the radiation curable material before curing but becomes incompatible after curing.

11. The array of microcups of claim 9 wherein said latent light scattering material is a thermally or photochemically triggered gas-releasing material.

12. The array of microcups of claim 11 wherein said thermally or photochemically triggered gas-releasing material is selected from a group consisting Of CO₂ producing carboxylic acids, bicyclic lactones or heterocycles;

CO producing ketones or bicyclic adducts;

SO and SO₂ producing sulfones, sulfonyloxy compounds or heterocycles;

N₂ producing azoalkanes, azides, diazomethanes, N-nitroso compounds, diazo, triazo or tetraazo heterocycles;

COS producing xanthates and O₂ producing endoperoxides.

13. The array of microcups of claim 11 wherein said thermally or photochemically triggered gas-releasing material is a phenol, tropolone, pyridine, pyrazine, pyrrole or a halogenated derivative thereof.

14. The array of microcups of claim 1 wherein said opaque partition walls are colored.

15. The array of microcups of claim 1 wherein the inside surface of the partition walls is of the same color as that of the electrophoretic composition.

16. The array of microcups of claim 15 wherein the two sides of a partition wall are of different colors.

17. The array of microcups of claim 1 which is sandwiched between two electrode layers.

18. The array of microcups of claim 1 which is sandwiched between one electrode layer and one permanent substrate layer.

19. The array of microcups of claim 1 which is sandwiched between one electrode layer and one temporary substrate layer.

20. An array of microcups each of said microcups comprises

a) partition walls,

b) a black matrix layer with registration to the top surface of the partition walls,

c) an electrophoretic composition filled therein, and

d) a polymeric sealing layer which is formed from a sealing composition having a specific gravity lower than that of the electrophoretic composition and sealingly adheres to the partition walls to enclose the electrophoretic composition within each microcup.

21. The array of microcups of claim 20 wherein said black matrix layer is on the top surface of the partition walls.

22. The array of microcups of claim 20 wherein said black matrix layer is on the polymeric sealing layer.

23. The array of microcups of claim 20 which is sandwiched between one top electrode layer and one bottom electrode layer.

24. The array of microcups of claim 23 wherein said black matrix layer is on the top electrode layer or on the bottom electrode layer.

25. The array of microcups of claim 23 wherein said top electrode layer is applied with an adhesive layer.

26. The array of microcups of claim 25 wherein said black matrix layer is on the adhesive layer.

27. The array of microcups of claim 23 further comprising a top substrate layer coated or laminated over the top electrode layer.

28. The array of microcups of claim 27 wherein said black matrix layer is on the top substrate layer.

29. The array of microcups of claim 23 further comprising a bottom substrate layer coated or laminated over the bottom electrode layer.

30. The array of microcups of claim 29 wherein said black matrix layer is on the bottom substrate layer.

31. The array of microcups of claim 20 which is sandwiched between one electrode layer and one permanent or temporary substrate layer.

32. The array of microcups of claim 31 wherein a black matrix layer is on the electrode layer or the permanent substrate layer.

33. The array of microcups of claim 31 wherein said electrode layer or permanent substrate layer is applied with an adhesive layer.

34. The array of microcups of claim 33 wherein said black matrix layer is on the adhesive layer.

35. The array of microcups of claim 31 further comprising a substrate layer coated or laminated over the electrode layer.

36. The array of microcups of claim 35 wherein said black matrix layer is on the substrate layer.

37. The array of microcups of claim 20 wherein said black matrix layer is applied by printing, stamping or photolithography.

38. The electrophoretic display of claim 20 wherein said black matrix layer is applied by vapor deposition or sputtering with a shadow mask.

39. The electrophoretic display of claim 20 wherein the optical density of said black matrix layer is higher than 0.5.

40. The electrophoretic display of claim 39 wherein the optical density said black matrix layer is higher than 1.

41. The electrophoretic display of claim 20 wherein the thickness of the black matrix layer is in the range of from 0.005 μ

m to 5 μ

m.

42. The electrophoretic display of claim 41 wherein the thickness of the black matrix layer is in the range of from 0.01 μ

m to 2 μ

m.

43. The electrophoretic display of claim 20 further comprising a diffuser layer directly or indirectly above the black matrix layer.

44. The electrophoretic display of claim 20 wherein said black matrix layer is a highly crosslinked black matrix layer.

45. The electrophoretic display of claim 20 wherein said partition walls are opaque.

46. The electrophoretic display of claim 45 wherein said partition walls are white opaque.

47. The electrophoretic display of claim 45 wherein said partition walls are gray opaque.

48. The electrophoretic display of claim 20 wherein said partition walls are colored.

49. The electrophoretic display of claim 20 wherein the inside surface of the partition walls is of the same color as the electrophoretic composition.

50. The electrophoretic display of claim 49 wherein the two sides of a partition wall are of different colors.