Manufacturing process for electrophoretic display

• US 6,672,921 B1
• Filed: 06/28/2000
• Issued: 01/06/2004
• 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: Chen, Xianhai, Wu, Zarng-Arh George, Chan-Park, Mary, Liang, Rong-Chang, Zang, HongMei
• Primary Examiner(s): Ramsey, Kenneth J.
• Application Number:
  US09/606,654
• Time in Patent Office: 1,287 Days
• Field of Search: 445/24, 359/296, 264/496, 264/1.7
• 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 invention relates to a method of manufacturing a micro-cup array. Such an array may find use in a number of applications such as, for example, a video display. The micro-cups find particular use in electrophoretic or liquid crystal displays.

Claims

1. A process for manufacturing a micro-cup array, comprising:

a. coating, onto a male mold having an array of protrusions adapted for forming the micro-cup array to be manufactured, a thermoset or thermoplastic precursor composition to form a contiguous precursor layer on the male mold;

b. contacting the precursor layer with a transfer sheet;

c. curing the precursor layer to form the micro-cup array; and

d. releasing the micro-cup array from the male mold.

2. The process of claim 1 wherein said curing is by exposure to heat, moisture, or radiation.

3. The process of claim 1 wherein said precursor composition comprises crosslinkable resins, monomers, oligomers or polymers.

4. The process of claim 3 wherein said crosslinkable resins, monomers, oligomers or polymers are selected from the group consisting of polyvalent acrylate, polyvalent methacrylate, polyvalent vinyl, polyvalent epoxide, polyvalent allyl, and oligomers and polymers containing these crosslinkable functional groups.

5. The process of claim 1 wherein the precursor composition is coated at a temperature near or above its glass transition temperature.

6. The process of claim 5 wherein the glass transition temperature is from about −

70°

C. to about 150°

C.

7. The process of claim 6 wherein the glass transition temperature is from about −

20°

C. to about 50°

C.

8. The process of claim 1 wherein the precursor composition further comprises a plasticizer, organic solvent, or solvent mixture.

9. The process of claim 1 wherein the male mold is selected from the group comprising a belt, a roller, and a sheet.

10. The process of claim 9 wherein the male mold is a belt.

11. The process of claim 1 wherein the male mold or the precursor is heated from between about 40°

C. to about 200°

C.

12. The process of claim 1 wherein the micro-cup array is post-cured after being released from the male mold.

13. The process of claim 1 wherein the transfer sheet is selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyvinyl fluoride, polyaramid, polyimide, polycycloolefin, polysulfone, epoxy, and their composites.

14. A process for manufacturing a micro-cup array for an electrophoretic or liquid crystal display, comprising:

a. coating, onto a male mold having an array of protrusions adapted for forming the micro-cup array to be manufactured, a thermoset or thermoplastic precursor composition to form a contiguous precursor layer on the male mold;

b. contacting the precursor layer with a transparent substrate having a patterned transparent conductor layer facing the precursor layer;

c. uniformly applying pressure to the substrate;

d. curing the precursor layer to form a micro-cup array adherent to the transparent substrate; and

e. releasing the micro-cup array from the male mold.

15. The process of claim 14 wherein said curing is by exposure to heat, moisture, or radiation.

16. The process of claim 14 wherein said precursor composition comprises crosslinkable resins, monomers, oligomers or polymers.

17. The process of claim 16 wherein said crosslinkable resins, monomers, oligomers or polymers are selected from the group consisting of polyvalent acrylate, polyvalent methacrylate, polyvalent vinyl, polyvalent epoxide, polyvalent allyl, and oligomers and polymers containing these crosslinkable functional groups.

18. The process of claim 14 wherein the precursor composition is coated at a temperature near or above its glass transition temperature.

19. The process of claim 18 wherein the glass transition temperature is from about −

70°

C. to about 150°

C.

20. The process of claim 19 wherein the glass transition temperature is from about −

20°

C. to about 50°

C.

21. The process of claim 14 wherein the precursor composition further comprises a plasticizer, organic solvent, or solvent mixture.

22. The process of claim 14 wherein the male mold is selected from the group comprising a belt, a roller, and a sheet.

23. The process of claim 22 wherein the male mold is a belt.

24. The process of claim 14 wherein the male mold or the precursor is heated from between about 40°

C. to about 200°

C.

25. The process of claim 14 wherein the micro-cup array is post-cured after being released from the male mold.

26. The process of claim 14 wherein the transparent substrate is selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyvinyl fluoride, polyaramid, polyimide, polycycloolefin, polysulfone, epoxy, and their composites.

27. The process of claim 14 wherein the patterned transparent conductor layer comprises indium tin oxide lines having a width matched to the protrusions of the male mold.

28. The process of claim 14 herein the pattern of the patterned transparent conductor layer is registered to the protrusions of the male mold.

29. A process for the manufacture of an electrophoretic display, comprising:

a. preparing an array of micro-cups on a conductor film by coating a layer of thermoset or thermoplastic precursor on a first conductor film followed by forming the array of micro-cups by embossing the precursor layer with a male mold or imagewise exposing the precursor layer and removing the unexposed areas;

b. filling the thus-formed micro-cups with a dielectric fluid containing at least a charged pigment suspension in a dielectric solvent or solvent mixture;

c. sealing the filled micro-cups to form an array of electrophoretic cells; and

d. laminating the array of electrophoretic cells, on a side of the array opposite the side facing the first conductor film, with a second conductor film pre-coated with an adhesive layer.

30. A process for the manufacture of a multi-color electrophoretic display, comprising the steps of:

a. preparing an array of micro-cups on a conductor film by coating a layer of thermoset or thermoplastic precursor on a first conductor film followed by forming the array of micro-cups by embossing the precursor layer with a male mold or imagewise exposing the precursor layer and removing the unexposed areas;

b. laminating the array of micro-cups with a layer of positive photoresist to seal the micro-cups;

c. imagewise exposing the positive photoresist to selectively open the micro-cups in a predetermined area;

d. filling the opened micro-cups with a dielectric fluid comprising at least a white pigment dispersion in a dielectric solvent or solvent mixture containing a dye or pigment dispersion of a first color;

e. sealing the filled micro-cups to form electrophoretic cells;

f. repeating steps c) to e) in different areas of the array using dielectric fluids of different colors;

g. removing any residual positive photoresist; and

h. laminating the array of electrophoretic cells, on a side of the array opposite the side facing the first conductor film, with a second conductor film precoated with an adhesive layer.