Electrophoretic display and process for its manufacture

• US 7,112,114 B2
• Filed: 12/01/2005
• Issued: 09/26/2006
• 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, Zang, Hongmei
• Primary Examiner(s): Dang, Hung Xuan
• Assistant Examiner(s): TRA, TUYEN Q
• Application Number:
  US11/293,194
• Publication Number:
  US 20060082864A1
• Time in Patent Office: 299 Days
• Field of Search: 359/296, 345/107, 430/32, 430/34, 430/38, 524/474, 204/450, 264/496, 264/1.7, 445/24
• US Class Current: 445/24
• CPC Class Codes: G02F 1/133305 Flexible substrates, e.g. plastics, organic film
• 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 1/1339 Gaskets; Spacers; Sealing 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 application is directed to electrophoretic displays and semi-finished display panels comprising display cells prepared from the microcup and top-sealing technologies.

Claims

1. A process for the preparation of a semi-finished display panel, which process comprises the steps of:

a) coating a layer of a thermoplastic, thermoset or precursor thereof on a temporary substrate layer followed by embossing the coated layer with a male mold or imagewise exposing a layer of a radiation curable composition coated on a temporary substrate layer followed by removing unexposed areas, to form an array of microcups;

b) filling the microcups with a charged pigment dispersion in a dielectric solvent or solvent mixture;

c) top-sealing the microcups with a sealing composition having a specific gravity lower than that of said dielectric solvent or solvent mixture; and

d) applying a conductor layer or a permanent substrate layer onto the top-sealed microcups.

2. The process of claim 1 wherein said thermoplastic or thermoset precursor is selected from the group consisting of polyvalent acrylates or methacrylates, polyvalent vinyls, polyvalent epoxides, polyvalent isocyanates, polyvalent allyls and oligomers or polymers comprising a crosslinkable functional group.

3. The process of claim 1 wherein said embossing is carried out at a temperature near or above the glass transition temperature of said thermoplastic, thermoset or precursor thereof.

4. The process of claim 1 wherein the male mold is released before, during or after the embossed layer is hardened.

5. The process of claim 1 wherein said radiation curable composition comprises a material selected from the group consisting of polyvalent acrylates or methacrylates, polyvalent vinyls, polyvalent epoxides, polyvalent isocyanates, polyvalent allyl and oligomers or polymers comprising a crosslinkable functional group.

6. The process of claim 1 wherein said imagewise exposing is accomplished by UV, visible light, near IR or electron beam radiation.

7. A process for the manufacture of a semi-finished display panel, which process comprises the steps of:

a) coating a layer of a thermoplastic, thermoset or precursor thereof on a conductor layer or a permanent substrate layer followed by embossing the coated layer with a male mold or imagewise exposing a layer of a radiation curable composition coated on a conductor layer or a permanent substrate layer followed by removing unexposed areas, to form an array of microcups;

b) filling the microcups with a charged pigment dispersion in a dielectric solvent or solvent mixture;

c) top-sealing the microcups with a sealing composition having a specific gravity lower than that of said dielectric solvent or solvent mixture; and

d) applying a temporary substrate layer onto the top-sealed microcups.

8. The process of claim 7 wherein said thermoplastic or thermoset precursor is selected from the group consisting of polyvalent acrylates or methacrylates, polyvalent vinyls, polyvalent epoxides, polyvalent isocyanates, polyvalent allyls and oligomers or polymers comprising a crosslinkable functional group.

9. The process of claim 7 wherein said embossing is carried out at a temperature near or above the glass transition temperature of said thermoplastic, thermoset or precursor thereof.

10. The process of claim 7 wherein the male mold is released before, during or after the embossed layer is hardened.

11. The process of claim 7 wherein said radiation curable composition comprises a material selected from the group consisting of polyvalent acrylates or methacrylates, polyvalent vinyls, polyvalent epoxides, polyvalent isocyanates, polyvalent allyl and oligomers or polymers comprising a crosslinkable functional group.

12. The process of claim 7 wherein said imagewise exposing is accomplished by UV, visible light, near IR or electron beam radiation.

13. A process for the manufacture of a multi-color semi-finished display panel, which process comprises the steps of:

a) coating a layer of a thermoplastic, thermoset or precursor thereof on a temporary substrate layer followed by embossing the coated layer with a male mold or imagewise exposing a layer of a radiation curable composition coated on a temporary substrate layer followed by removing unexposed areas, to form an array of microcups;

b) laminating or coating the microcups with a layer of a positive photoresist;

c) imagewise exposing the positive photoresist to selectively open the microcups in a predetermined area;

d) filling the opened microcups with a charged pigment dispersion in a dielectric solvent or solvent mixture which comprises a dye or pigment of a first color;

e) top-sealing the microcups filled with said charged pigment dispersion in said dielectric solvent or solvent mixture of the first color;

f) repeating steps c) to e) in different areas to generate microcups filled with charged pigment dispersion in dielectric solvent or solvent mixture of different colors;

g) removing residual positive photoresist, if any; and

h) applying a conductor layer or a permanent substrate layer onto the top-sealed microcups.

14. The process of claim 13 wherein said thermoplastic or thermoset precursor is selected from the group consisting of polyvalent acrylates or methacrylates, polyvalent vinyls, polyvalent epoxides, polyvalent isocyanates, polyvalent allyls and oligomers or polymers comprising a crosslinkable functional group.

15. The process of claim 13 wherein said embossing is carried out at a temperature near or above the glass transition temperature of said thermoplastic, thermoset or precursor thereof.

16. The process of claim 13 wherein the male mold is released before, during or after the embossed layer is hardened.

17. The process of claim 13 wherein said radiation curable composition comprises a material selected from the group consisting of polyvalent acrylates or methacrylates, polyvalent vinyls, polyvalent epoxides, polyvalent isocyanates, polyvalent allyl and oligomers or polymers comprising a crosslinkable functional group.

18. The process of claim 13 wherein said imagewise exposing is accomplished by UV, visible light, near IR or electron beam radiation.

19. The process of claim 13 wherein said top sealing is accomplished with a sealing composition having a specific gravity lower than that of said dielectric solvent or solvent mixture.

20. A process for the manufacture of a multi-color semi-finished display panel, which process comprises the steps of:

a) coating a layer of a thermoplastic, thermoset or precursor thereof on a conductor layer or a permanent substrate layer followed by embossing the coated layer with a male mold or imagewise exposing a layer of a radiation curable composition coated on a conductor layer or a permanent substrate layer followed by removing unexposed areas, to form an array of microcups;

b) laminating or coating the microcups with a layer of a positive photoresist;

c) imagewise exposing the positive photoresist to selectively open the microcups in a predetermined area;

d) filling the opened microcups with a charged pigment dispersion in a dielectric solvent or solvent mixture which comprises a dye or pigment of a first color;

e) top-sealing the microcups filled with said charged pigment dispersion in said dielectric solvent or solvent mixture of the first color;

f) repeating steps c) to e) in different areas to generate microcups filled with charged pigment dispersion in dielectric solvent or solvent mixture of different colors;

g) removing residual positive photoresist, if any; and

h) applying a temporary substrate layer onto the top-sealed microcups.

21. The process of claim 20 wherein said thermoplastic or thermoset precursor is selected from the group consisting of polyvalent acrylates or methacrylates, polyvalent vinyls, polyvalent epoxides, polyvalent isocyanates, polyvalent allyls and oligomers or polymers comprising a crosslinkable functional group.

22. The process of claim 20 wherein said embossing is carried out at a temperature near or above the glass transition temperature of said thermoplastic, thermoset or precursor thereof.

23. The process of claim 20 wherein the male mold is released before, during or after the embossed layer is hardened.

24. The process of claim 20 wherein said radiation curable composition comprises a material selected from the group consisting of polyvalent acrylates or methacrylates, polyvalent vinyls, polyvalent epoxides, polyvalent isocyanates, polyvalent allyl and oligomers or polymers comprising a crosslinkable functional group.

25. The process of claim 20 wherein said imagewise exposing is accomplished by UV, visible light, near IR or electron beam radiation.

26. The process of claim 20 wherein said top sealing is accomplished with a sealing composition having a specific gravity lower than that of said dielectric solvent or solvent mixture.