Electrophoretic display with color filters

• US 6,850,355 B2
• Filed: 07/26/2002
• Issued: 02/01/2005
• Est. Priority Date: 07/27/2001
• Status: Expired due to Term

• Current Assignee: E Ink California, LLC (E Ink Corporation)
• Original Assignee: SiPix Imaging, Inc. (E Ink Holdings Incorporated)
• Inventors: Wu, Zarng-Arh George, Liang, Rong-Chang, Tseng, Scott C-J, Zang, Hongmei
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): CHOI, WILLIAM C
• Application Number:
  US10/206,859
• Publication Number:
  US 20030021005A1
• Time in Patent Office: 921 Days
• Field of Search: 359/296, 359/243, 359/240, 345/107, 345/108, 345/44, 345/84, 430/35, 430/45, 204/478, 204/485
• 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 invention relates to an electrophoretic display comprising a transparent top viewing electrode, a bottom electrode and a plurality of isolated cells having well-defined size, shape and aspect ratio, said cells filled with charged pigment particles dispersed in a dielectric solvent or solvent mixture, and a color filter placed with the top transparent electrode.

Claims

1. An electrophoretic display comprising

(a) a transparent tops viewing electrode comprising a transparent conductor film on a transparent plastic substrate layer;

(b) a bottom electrode;

(c) a plurality of isolated cells having well-defined size, shape and aspect ratio, said cells are filled with an electrophoretic fluid comprising charged pigment particles dispersed in a dielectric solvent or solvent mixture and sealed with a sealing layer formed from a sealing composition having a specific gravity lower than that of said electrophoretic fluid; and

(d) a color filter layer which is on top of the transparent plastic substrate layer, or is between the transparent conductor film and the transparent plastic substrate layer, or is underneath the transparent conductor film.

2. The electrophoretic display of claim 1 wherein the bottom electrode is a conductor film or a substrate containing thin film transistors.

3. The electrophoretic display of claim 1 wherein the cells are substantially uniform in size and shape.

4. The electrophoretic display of claim 1 wherein the plurality of cells comprises cells of different sizes and shapes.

5. The electrophoretic display of claim 1 wherein the cells are non-spherical.

6. The electrophoretic display of claim 1 wherein the cells are formed from microcups with an opening area ranging from about 10² to about 1×

10⁶ μ

m².

7. The electrophoretic display of claim 1 wherein the cells are formed from microcups with an opening area ranging from about 10³ to about 1×

10⁵ μ

m².

8. The electrophoretic display of claim 1 wherein the cells are formed from microcups with an opening having a circular, polygonal, hexagonal, rectangular or square shape.

9. The electrophoretic display of claim 1 wherein the cells have a depth in the range from about 5 to about 100 microns.

10. The electrophoretic display of claim 1 wherein the cells have a depth in the range from about 10 to about 50 microns.

11. The electrophoretic display of claim 1 wherein the cells have an opening to total area ratio in the range from about 0.05 to about 0.95.

12. The electrophoretic display of claim 1 wherein the cells have an opening to total area ratio in the range from about 0.4 to about 0.9.

13. The electrophoretic display of claim 1 is a monochrome display.

14. The electrophoretic display of claim 1 is a multiple color display.

15. The electrophoretic display of claim 1 wherein said color filter is of the same color or different colors for said cells.

16. The electrophoretic display of claim 1 wherein said color filter comprises stripes of red, green and blue color.

17. The electrophoretic display of claim 1 wherein said color filter further comprises a black matrix.

18. The electrophoretic display of claim 1 wherein said particles are white or colored.

19. The electrophoretic display of claim 1 wherein said dielectric solvent in said cells are of the same colors or of different colors.

20. The electrophoretic display of claim 19 wherein said dielectric solvent in said cells is black.

21. The electrophoretic display of claim 1 wherein said particles carry opposite charges.

22. The electrophoretic display of claim 21 wherein the positively charged particles are white and the negatively charged particles are colored.

23. The electrophoretic display of claim 21 wherein the positively charged particles are colored and the negatively charged particles are white.

24. The electrophoretic display of claim 1 wherein said sealing composition is a radiation curable composition.

25. The electrophoretic display of claim 1 wherein said sealing composition is a heat or moisture curable composition.

26. The electrophoretic display of claim 1 wherein said sealing composition comprises a thermoplastic elastomer.

27. The electrophoretic display of claim 1 wherein said color filter layer is between the sealing layer and the transparent conductor film.

28. An electrophoretic display comprising

(a) a transparent top viewing electrode comprising a conductor film on a transparent plastic substrate layer;

(b) a bottom electrode;

(c) a plurality of isolated cells having well-define size, shape and aspect ratio, said cells are filled with an electrophoretic fluid comprising charged pigment particles dispersed in a dielectric solvent or solvent mixture; and

(e) a color filter layer which in between the transparent conductor film and the transparent plastic substrate layer or is underneath the transparent conductor film.