Electrochromic or electrodeposition display and novel process for their manufacture

• US 7,245,414 B2
• Filed: 09/10/2003
• Issued: 07/17/2007
• Est. Priority Date: 09/10/2002
• Status: Active Grant

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: SiPix Imaging, Inc. (E Ink Holdings Incorporated)
• Inventors: Liang, Rong-Chang, Hou, Jack, Ananthavel, Sundaravel P.
• Primary Examiner(s): THOMPSON, TIMOTHY J
• Application Number:
  US10/660,381
• Publication Number:
  US 20060139724A1
• Time in Patent Office: 1,406 Days
• Field of Search: 359/290, 359/291, 359/295, 359/298, 359/245, 359/270, 359/265, 359/296, 359/297
• US Class Current: 359/265
• CPC Class Codes: G02F 1/133377 Cells with plural compartments or having plurality of liquid crystal microcells partitioned by walls, e.g. one microcell per pixel
• CPC Class Codes: G02F 1/1503 caused by oxidation-reduction reactions in organic liquid solutions, e.g. viologen solutions
• CPC Class Codes: G02F 1/1506 caused by electrodeposition, e.g. electrolytic deposition of an inorganic material on or close to an electrode
• CPC Class Codes: G02F 1/153 Constructional details
• CPC Class Codes: G02F 1/1533 structural features not otherwise provided for
• CPC Class Codes: G02F 1/161 Gaskets; Spacers; Sealing of cells; Filling or closing of cells

Abstract

The present invention is directed to an improved electrodeposition and an electrochromic display. The display cells formed from microcups are filled with an electrolyte fluid and are individually sealed with a polymeric sealing layer.

Claims

1. An electroechromic or electrodeposition display comprising a plurality of cells, each of said cells comprises:

(a) surrounding partition walls,

(b) an electrochromic fluid or electrolytic fluid filled therein, and

(c) a polymeric sealing layer which is formed from a sealing composition having a specific gravity lower than that of the electrochromic fluid or electrolytic fluid to enclose the electrochromic fluid or electrolytic fluid within each cell.

2. The display of claim 1 wherein said cell is partially filled.

3. The display of claim 2 wherein said polymeric sealing layer is in contact with said electrochromic fluid or electrolytic fluid filled in said cell.

4. The display of claim 1 wherein said electrolytic fluid comprises a metal salt dissolved in a solvent or in a polymer matrix.

5. The display of claim 4 wherein said metal salt is a silver salt.

6. The display of claim 5 wherein said silver salt is silver halide or silver nitrate.

7. The display of claim 4 wherein said polymer matrix is formed of a material selected from the group consisting of poly(ethylene oxide), polyvinylpyrrolidone, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, gelatin, gum Arabic and their copolymers.

8. The display of claim 4 wherein said solvent is a non-aqueous solvent.

9. The display of claim 8 wherein said non-aqueous solvent is selected from the group consisting of dimethylsulfoxide, dimethyl formamide, diethyl formamide, N, N-dimethylacetamide, N-methylpropionic acid amide, N-methylpyrrolidone, propylene carbonate, acetonitrile, 2-methoxyethanol, 2-ethoxyethanol, dimethoxymethane, glycerine carbonate, 2-methylglutaronitrile and γ

-butyrolactone.

10. The display of claim 4 wherein said solvent is a mixture of aqueous and non-aqueous solvents.

11. The display of claim 4 wherein the concentration of said metal salt is from about 0.03 to about 2.0 mol/L.

12. The display of claim 11 wherein the concentration of said metal salt is from about 0.05 to about 2.0 mol/L.

13. The display of claim 4 wherein said electrolytic fluid further comprises a supporting electrolyte.

14. The display of claim 13 wherein said supporting electrolyte is lithium halide, sodium halide, potassium halide, calcium halide or a halogenated quaternary ammonium salt.

15. The display of claim 13 wherein the concentration of said supporting electrolyte is from about 0.5 to about 5 times said metal salt.

16. The display of claim 1 wherein each of said cells comprises said electrochromic fluid filled therein and said electrochromic fluid comprises a redox chromophore, an electrolyte and an inert solvent.

17. The display of claim 16 wherein said redox chromphore is a viologen derivative.

18. The display of claim 17 wherein said viologen is his (2-phosphonoethyl)-4,4′

-bipyridinium dichloride.

19. The display of claim 16 wherein said electrolyte is lithium perchlorate, lithium triflate or tetrabutylammonium triflate.

20. The display of claim 16 wherein said inert solvent is γ

-butyrolactone or 3-methoxypropionitrile.

21. The display of claim 16 wherein said electrochromic fluid further comprises white pigment particles of rutile titania, BaSO₄ or zinc oxide.

39. The display of claim 1 wherein said sealing composition comprises a thermoplastic elastomer, a diene rubber, a polyurethane or a block copolymer thereof.

40. The display of claim 39 wherein said thermoplastic elastomer is a Kraton polymer.

41. The display of claim 39 wherein said diene rubber is polybutadiene, polychloroprene, polyisoprene or poly(styrene-co-butadiene).

42. The display of claim 39 wherein said sealing composition is in a solvent selected from the group consisting of methyl ethyl ketone, methyl propyl ketone, ethyl acetate, isopropyl acetate, butyl acetate, toluene, xylene, alkanes, cyclohexane, decalin, and dodecylbenzene.

50. The display of claim 1 wherein said electrochromic fluid or electrolytic fluid further comprises density-matched reflecting particles.

51. The display of claim 50 wherein said density-matched reflecting particles are formed of TiO₂, ZnO, BaSO₄ or silica.

22. An electrochromic or electrodeposition display comprising

a) a top electrode plate and a bottom electrode plate, at least one of which is transparent;

and

b) a plurality of cells enclosed between the two electrode plates, each of said cells comprising

(i) surrounding partition walls,

(ii) an electrochromic fluid or electrolytic fluid filled therein, and

(iii) a polymeric sealing layer which is formed from a sealing composition having a specific gravity lower than that of the electrochromic fluid or electrolytic fluid to enclose the electrochromic fluid or electrolytic fluid within each cell.

23. The display of claim 22 wherein the thickness of the bottom of said cells is less than about 2 μ

m.

24. The display of claim 23 wherein the thickness of the bottom of said cells is less than about 1 μ

m.

25. The display of claim 22 wherein said cells are formed of a composition comprising a thermoplastic, thermoset or a precursor thereof.

26. The display of claim 25 wherein said composition further comprises a gas absorbing material.

27. The display of claim 26 wherein said gas absorbing material is a chlorine, hydrogen or oxygen absorbing material.

28. The display of claim 27 wherein said chlorine, hydrogen or oxygen absorbing material is selected from the group consisting of rubbers, nitrile rubbers, styrene-butadiene copolymers and norbornenes.

29. The display of claim 27 wherein said composition further comprises a catalyst for a hydrogenation or oxidation reaction.

30. The display of claim 29 wherein said catalyst is a complex of Co or V.

31. The display of claim 30 wherein said complex of Co or V is Co acetoacetate, Co acetylacetonate, V acetoacetate or V acetylacetonate.

32. The display of claim 22 wherein said sealing composition comprises a thermoplastic, a thermoset or a precursor thereof.

33. The display of claim 32 wherein said sealing composition further comprises a chlorine, hydrogen or oxygen absorbing material.

34. The display of claim 33 wherein said chlorine, hydrogen or oxygen absorbing material is selected from the group consisting of rubbers, nitrile rubbers, styrene-butadiene copolymers and norbomenes.

35. The display of claim 32 wherein said sealing composition further comprises particles or fibers of a conductive polymer or a doped derivative thereof, carbon black, graphite, a metal oxide or metal.

36. The display of claim 22 wherein said polymeric sealing layer has a vertical conductivity which is the conductivity in the direction perpendicular to the electrode plates and a horizontal conductivity which is the conductivity in the direction parallel to the electrode plates, and said vertical conductivity is higher than said horizontal conductivity.

37. The display of claim 35 wherein said particles have a concentration from about 1 to about 20% by volume.

38. The display of claim 37 wherein said particles have a concentration from about 5 to about 15% by volume.

43. The display of claim 22 wherein said top electrode plate is laminated over said polymeric sealing layer with an adhesive layer.

44. The display of claim 43 wherein said adhesive layer further comprises a gas absorbing material.

45. The display of claim 43 wherein said adhesive layer further comprises particles or fibers of a conductive polymer or a doped derivative thereof, carbon black, graphite, a metal oxide or metal.

46. The display of claim 43 wherein said adhesive layer has a vertical conductivity which is the conductivity in the direction perpendicular to the electrode plates and a horizontal conductivity which is the conductivity in the direction parallel to the electrode plates, and said vertical conductivity is higher than said horizontal conductivity.

47. The display of claim 22 further comprising a primer layer between the cells and said bottom electrode plate.

48. The display of claim 47 wherein said primer layer comprises particles or fibers of a conductive polymer or a doped derivative thereof, carbon black, graphite, a metal oxide or metal.

49. The display of claim 47 wherein said primer layer comprises a gas absorbing material.

52. The display of claim 43 wherein said gas absorbing material is a chlorine, hydrogen or oxygen absorbing material.

53. The display of claim 52 wherein said chlorine, hydrogen or oxygen absorbing material is selected from the group consisting of rubbers, nitrile rubbers, styrene-butadiene copolymers and norbornenes.