Electrophoretic display and process for its manufacture

• US 20060164715A1
• Filed: 08/10/2005
• Published: 07/27/2006
• Est. Priority Date: 03/03/2000
• Status: Active Grant

• Current Assignee: E Ink California, LLC (E Ink Corporation)
• Original Assignee: SiPix Imaging, Inc. (E Ink Holdings Incorporated)
• Inventors: Chan-Park, Mary, Wu, Zarng-Arh George, Liang, Rong-Chang, Zang, HongMei, Tseng, Scott C-J
• Granted Patent: US 7,522,332 B2
• Time in Patent Office: Days
• US Class Current: 359/296
• CPC Class Codes: B01J 13/16 Interfacial polymerisation
• CPC Class Codes: C08G 18/0866 the dispersing or dispersed phase being an aqueous medium
• CPC Class Codes: C08G 18/5015 having fluorine atoms
• CPC Class Codes: C08G 18/5039 containing amide groups
• CPC Class Codes: C08G 18/5066 having halogens in addition to nitrogen
• CPC Class Codes: C08G 18/792 formed by oligomerisation of aliphatic and/or cycloaliphatic isocyanates or isothiocyanates
• CPC Class Codes: C08G 18/8038 with compounds of C08G18/3225
• CPC Class Codes: C08G 18/8087 containing halogen atoms
• CPC Class Codes: G02F 1/161 Gaskets; Spacers; Sealing of cells; Filling or closing of cells
• CPC Class Codes: G02F 1/167 by electrophoresis
• 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 cells which are filled with charged particles dispersed in a solvent and are individually sealed with a polymeric sealing layer.

Claims

1. A process for forming an electrophoretic display comprising a plurality of cells, which process comprises the steps of:

a) filling each of said cells with an electrophoretic fluid comprising charged pigment particles dispersed in a dielectric solvent, and

b) hardening in situ a polymeric sealing layer which polymeric sealing layer forms a contiguous film on said electrophoretic fluid to enclose said electrophoretic fluid within each of said cells.

2. The process of claim 1 wherein said cell is partially filled with said electrophoretic fluid.

3. The process of claim 1 wherein said polymeric sealing layer is formed from a sealing composition comprising a material selected from the group consisting of polyvalent acrylate or methacrylate, cyanoacrylates, polyvalent vinyl, polyvalent epoxide, polyvalent isocyanate, polyvalent allyl, and oligomers or polymers containing crosslinkable functional groups.

4. The process of claim 3 wherein said composition further comprises an additive selected from the group consisting of surfactants, antioxidants, initiators, catalysts, crosslinkers, thickeners, polymer binders, pigments, dyes and fillers.

5. The process of claim 4 wherein said filler is selected from the group consisting of silica, CaCO₃, BaSO₄, TiO₂, metal particles, metal oxides and carbon black.

6. The process of claim 3 wherein said polyvalent vinyl is vinylbenzene, vinylsilane or vinylether.

7. The process of claim 1 wherein said polymeric sealing layer is formed from a sealing composition having a specific gravity lower than that of the electrophoretic fluid.

8. The process of claim 7 wherein said sealing composition comprises a thermoplastic, thermoset or a precursor thereof.

9. The process of claim 7 wherein said sealing composition comprises a thermoplastic or thermoset precursor.

10. The process of claim 1 wherein said hardening of said polymeric sealing layer is accomplished by solvent evaporation, interfacial reaction, moisture, heat or radiation.

11. A sealing process for the manufacture of an electrophoretic display, which process comprises hardening a sealing composition on top of an electrophoretic fluid wherein said sealing composition has a specific gravity lower than that of the electrophoretic fluid.

12. A sealing process for the manufacture of an electrophoretic display, which process comprises

a) dispersing a sealing composition in an electrophoretic fluid wherein said sealing composition has a specific gravity lower than that of the electrophoretic fluid;

and

b) hardening said sealing composition during or after it phase separates and forms a supernatant layer above the electrophoretic fluid.

13. A sealing process for the manufacture of an electrophoretic display which process comprises

a) overcoating a sealing composition onto an electrophoretic fluid wherein said sealing composition is immiscible with the electrophoretic fluid;

and

b) hardening said sealing composition.

14. The sealing process of claim 13 wherein said sealing composition has a specific gravity lower than that of the electrophoretic fluid.

15. An electrophoretic display comprising an electrophoretic fluid wherein said electrophoretic fluid is enclosed by partition walls and a sealing layer formed from a composition having a specific gravity lower than that of the electrophoretic fluid.