Transmissive or reflective liquid crystal display

• US 20070042135A1
• Filed: 08/17/2006
• Published: 02/22/2007
• Est. Priority Date: 11/25/2002
• Status: Active Grant

• Current Assignee: E Ink California, LLC (E Ink Holdings Incorporated)
• Original Assignee: SiPix Imaging, Inc. (E Ink Holdings Incorporated)
• Inventors: Liang, Rong-Chang, Zang, HongMei, Li, Ying-Syi, Tseng, Scott
• Granted Patent: US 8,023,071 B2
• Time in Patent Office: Days
• US Class Current: 428/1.100
• CPC Class Codes: C09K 2323/00 Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition
• CPC Class Codes: C09K 2323/05 Bonding or intermediate layer characterised by chemical composition, e.g. sealant or spacer
• 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 1/13475 in which at least one liquid crystal cell or layer is doped with a pleochroic dye, e.g. GH-LC cell G02F1/13476 takes precedence

Abstract

This invention relates to a liquid crystal display with improved contrast ratio, switching performance, reflectivity at the Dmin state and structural integrity, and methods for its manufacture. The liquid crystal display of the present invention comprises microcups as display cells, wherein the microcups are formed from a microcup composition and filled with a liquid crystal composition.

Claims

1. A liquid crystal display comprising microcups as display cells wherein said microcups are:

a) formed from a microcup composition comprising a speed enhancing monomer or oligomer;

b) filled with a liquid crystal composition; and

c) sealed with a sealing layer which is being hardened when in contact with the liquid crystal composition filled in the microcups.

2. The liquid crystal display of claim 1 wherein said microcup composition comprises an embossable material.

3. The liquid crystal display of claim 2 wherein said embossable material is a thermoplastic, a thermoset, or a precursor thereof.

4. The liquid crystal display of claim 3 wherein said thermoplastic, thermoset, or precursor thereof is selected from the group consisting of a multifunctional acrylate, a multifunctional methacrylate, a vinyl ether, an epoxide, and an oligomer or a polymer thereof.

5. A liquid crystal display comprising microcups as display cells which are:

a) formed from a microcup composition comprising a monomer or oligomer having at least one polar group; and

b) filled with a liquid crystal composition.

6. The liquid crystal display of claim 5 wherein said polar group is selected from the group consisting of nitro, hydroxyl, carboxyl, halo, cyano and sulfonate.

7. The liquid crystal display of claim 5 wherein said microcup composition comprises an embossable material.

8. The liquid crystal display of claim 7 wherein said embossable material is a thermoplastic, a thermoset, or a precursor thereof.

9. The liquid crystal display of claim 8 wherein said thermoplastic, thermoset, or precursor thereof is selected from the group consisting of a multifunctional acrylate, a multifunctional methacrylate, a vinyl ether, an epoxide, and an oligomer or a polymer thereof.

10. A liquid crystal display comprising microcups as display cells which are:

a) formed from a microcup composition comprising a speed enhancing filler material; and

b) filled with a liquid crystal composition.

11. The liquid crystal display of claim 10 wherein said microcup composition comprises an embossable material.

12. The liquid crystal display of claim 11 wherein said embossable material is a thermoplastic, a thermoset, or a precursor thereof.

13. The liquid crystal display of claim 12 wherein said thermoplastic, thermoset, or precursor thereof is selected from the group consisting of a multifunctional acrylate, a multifunctional methacrylate, a vinyl ether, an epoxide, and an oligomer or a polymer thereof.

14. The liquid crystal display of claim 10 wherein said speed enhancing filler material is a low resistance filler, a conductive filler or a filler material having a high dielectric constant.

15. The liquid crystal display of claim 14 wherein said low resistance filler is a metal oxide, polyether block amide elastomer, or polyaniline.

16. The liquid crystal display of claim 14 wherein said low resistance filler is a fiber material.

17. The liquid crystal display of claim 10 wherein said filler material is zirconia, barium titanate, strontium titanate, or lead zirconate titanate.

18. A process for the manufacture of a liquid crystal display, which process comprises:

a) forming microcups from a microcup composition comprising a speed enhancing monomer or oligomer or a speed enhancing filler material;

b) filling the microcups with a liquid crystal composition;

c) sealing the filled microcups with a sealing composition which is being hardened when in contact with the liquid crystal composition.

19. The process of claim 18 wherein said speed enhancing monomer or oligomer is a monomer or oligomer having at least one polar group.

20. The process of claim 18 wherein said speed enhancing filler material is a low resistance filler, a conductive filler or a filler material having a high dielectric constant.