Method of forming a composite

• US 20050079663A1
• Filed: 12/13/2002
• Published: 04/14/2005
• Est. Priority Date: 12/13/2001
• Status: Active Grant

• Current Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Original Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Inventors: Cross, Graham, Yasuda, Akio, Roberts, Anthony, Bloor, David, Masutani, Akira, Szablewski, Marek
• Granted Patent: US 8,153,192 B2
• Time in Patent Office: Days
• US Class Current: 438/200
• CPC Class Codes: C09K 19/544 as dispersing or encapsulating medium around the liquid crystal
• CPC Class Codes: C09K 2019/546 creating a polymeric network
• 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: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals

Abstract

The invention relates to a method of forming a composite, to composites and devices produced by said method, and to uses thereof.

Claims

1. A method of forming a composite containing a matrix component and at least one liq-uid crystal component, said at least one liquid crystal component being dispersed within said matrix, said matrix component having a first index of refraction and said at least one liquid crystal component having a second index of refraction, the difference between the first and the second index of refraction being variable over a range of val-ues, such that it is possible to adjust the difference between the first and the second in-dex to be small or approximately zero, whereby, as a result, a display cell containing said composite becomes transparent, said method comprising the following steps:

a) providing a matrix component,

b) providing at least one liquid crystal component, said liquid crystal component being optically absorbing,

c) adding the at least one liquid crystal component to the matrix component.

2. The method according to claim 1, comprising the additional step:

d) heating the composite containing the matrix component and at least one liquid crystal component to a temperature above the isotropic temperature of the liquid crystal component, but below the decomposition temperature/melting temperature of the matrix component.

3. The method according to claim 2, comprising the additional step:

e) cooling the composite to room temperature.

4. The method according to claim 2, wherein the heating occurs for 1-20 min-utes, preferably 1-10 minutes, more preferably 1-5 minutes, and the cooling occurs over a period of 1-60 minutes, preferably 1-40 minutes, more preferably 5-20 minutes.

5. The method according to claim 1, wherein the at least one liquid crystal component contains at least one optically absorbing component.

6. The method according to claim 5 wherein the at least one optically absorbing compo-nent is soluble in the at least one liquid crystal component.

7. The method according to claim 6, wherein the soluble optically absorbing component is selected from the group comprising dyes, compounds with permanent dipoles, rod-like structure materials, and nanotubes.

8. The method according to claim 7, wherein the soluble optically absorbing component is selected from the group comprising UV-sensitive dyes, UV-stable dyes, cis-trans isomer dyes, dichroic dyes and dipolar dyes.

9. The method according to claim 1, wherein the matrix component is a polymer-matrix-component, or a glass-based component or a combination of the two.

10. The method according to claim 9, wherein the polymer-matrix component is a pre-formed porous polymer matrix or is a polymer matrix, prepared by the PDLC-technique (polymer-dispersed liquid crystal-technique).

11. A composite obtainable by a method according to claim 1.

12. The composite according to claim 11, characterized in that it contains a liquid crystal component doped with a compound selected from the group comprising dyes, UV-sensitive dyes, UV-stable dyes, dichroic dyes, dyes with a permanent dipole, rod-like structure material and nanotubes.

13. A device containing a composite according to claim 11.

14. Use of a device according to claim 13, in a display, a smart window, a membrane, an optical valve, a Bragg grating, an optically sensitive memory, an infrared shutter, a gasflow sensor, a pressure sensor and/or a polarizer.

15. Use of a composite according to claim 11 in a display, a smart window, a membrane, an optical valve, a Bragg grating, an optically sensitive memory, an infrared shutter, a gasflow sensor, a pressure sensor and/or a polarizer.