Method of making a polymer dispersed liquid crystal by electrodeposition

• US 5,479,278 A
• Filed: 10/16/1992
• Issued: 12/26/1995
• Est. Priority Date: 10/21/1991
• Status: Expired due to Fees

• Current Assignee: Dai Nippon Printing Company Limited
• Original Assignee: Dai Nippon Printing Company Limited
• Inventors: Takeuchi, Satoshi, Maeda, Hiroki, Shindo, Tadafumi, Ando, Masayuki, Tabei, Tatsuya
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/961,168
• Time in Patent Office: 1,166 Days
• Field of Search: 359/51, 359/52, 359/68, 359/103, 428/1, 252/299.01, 252/299.1, 204/180.2, 204/181.4, 204/299, 204/181.1, 205/162, 205/104, 205/122
• US Class Current: 349/187
• CPC Class Codes: C09D 5/448 characterised by the additives used C09D5/4403 - C09D5/4476, C09D5/4492 take precedence
• CPC Class Codes: C09K 19/544 as dispersing or encapsulating medium around the liquid crystal
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals

Abstract

A liquid crystal optical device including a liquid crystal/polymer composite film including a matrix polymer composed mainly of a transparent resin having an ionic dissociative group and, dispersed therein, a liquid crystal particle; and conductive substrates sandwiching the liquid crystal/polymer composite film therebetween, at least one of the conductive substrates being transparent. A method for producing the liquid crystal optical device according to the present invention includes the steps of dispersing a liquid crystal in a dispersion medium composed mainly of water to prepare an oil-in-water type emulsion; preparing a composition for electrodeposition through the use of the resultant emulsion and a resin for a matrix polymer; electrodepositing the composition for electrodeposition on a conductive base material to form an electrodeposited coating; and drying the electrodeposited coating to form on the conductive base material a liquid crystal/polymer composite film including a matrix polymer and, dispersed therein, a liquid crystal particle.

Claims

1. A method for producing a liquid crystal optical device, comprising:

preparing an oil-in-water type emulsion by a membrane emulsification process comprising flowing a dispersion medium composed mainly of water along one surface of a film having a number of homogeneous through pores and forcibly passing the liquid crystal by means of a predetermined pressure through the film onto the other surface of the film and introducing the liquid crystal into the dispersion medium composed mainly of water to obtain the oil-in-water type emulsion;

preparing a composition for electrodeposition through the use of the resultant emulsion and a resin for a matrix polymer;

electrodepositing the composition for electrodeposition on a conductive base material to form an electrodeposited coating; and

drying the electrodeposited coating to form on the conductive base material a liquid crystal/polymer composite film comprising a matrix polymer and droplets of a liquid crystal material dispersed in the matrix polymer.

2. A method according to claim 1, further comprising the steps of patterning a resist to form a partition wall on the conductive base material for electrodeposition before the electrodepositing step is performed.

3. A method according to claim 2, further comprising the step of encapsulating a droplet of the liquid crystal material.

4. A method according to claim 2, wherein the dispersion medium composed mainly of water contains a surfactant.

5. A method according to claim 2, wherein said liquid crystal material comprises a dichroic dye.

6. A method according to claim 2, wherein a counter electrode having a shape similar to the conductive substrate to be electrodeposition-coated is used in the electrodeposition coating on the conductive base material.

7. A method according to claim 2, wherein a counter electrode having a shape congruent to the conductive substrate to be electrodeposition-coated is used in the electrodeposition coating on the conductive base material.

8. A method according to claim 1, wherein the film having a number of through pores comprises a porous glass.

9. A method according to claim 8, wherein the through pores of the film have pore diameters ranging from 0.1 to 1 μ

m.

10. A method according to claim 1, comprising the step of encapsulating a droplet of the liquid crystal material.

11. A method according to claim 1, wherein the dispersion medium composed mainly of water contains a surfactant.

12. A method according to claim 11, wherein said surfactant is a protective colloid comprising a polyvinyl alcohol compound.

13. A method according to claim 12, wherein said polyvinyl alcohol compound has a degree of polymerization of 300 to 1200 and a degree of saponification of 50 to 85%.

14. A method according to claim 1, wherein said liquid crystal material comprises a dichroic dye.

15. A method according to claim 1, wherein a counter electrode having a shape similar to the conductive substrate to be electrodeposition-coated is used in the electrodepositon coating on the conductive base material.

16. A method according to claim 1, wherein a counter electrode having a shape congruent to the conductive substrate to be electrodeposition-coated is used in the electrodepositon coating on the conductive base material.