Method of forming a composite

• US 8,153,192 B2
• Filed: 12/13/2002
• Issued: 04/10/2012
• Est. Priority Date: 12/13/2001
• Status: Expired due to Fees

• Current Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Original Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Inventors: Masutani, Akira, Yasuda, Akio, Roberts, Anthony, Szablewski, Marek, Bloor, David, Cross, Graham
• Primary Examiner(s): Norton, Nadine
• Assistant Examiner(s): Dahimene, Mahmoud
• Application Number:
  US10/498,169
• Publication Number:
  US 20050079663A1
• Time in Patent Office: 3,406 Days
• Field of Search: 427/162, 427/164
• US Class Current: 427/162
• 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 liquid 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 values, such that it is possible to adjust the difference between the first and the second index to be small or approximately zero, whereby, as a result, a display cell containing said composite becomes transparent, said method comprising:

providing a porous matrix having an interstitial space for taking up liquids, wherein pores in the porous matrix have a pore size in the range of 500 nm to 10 μ

m;

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

adding the at least one liquid crystal component to the porous matrix;

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

cooling the composite to a first temperature, wherein the composite, while at the first temperature, can be reversibly switched between a colored state and transparent state by applying an electric field directly to the composite.

2. The method according to claim 1, wherein the heating occurs for 1-20 minutes, and the cooling occurs over a period of 1-60 minutes.

3. The method according to claim 1 wherein the at least one optically absorbing component is soluble in the at least one liquid crystal component.

4. The method according to claim 3, wherein the soluble optically absorbing component is selected from the group comprising dyes, compounds with permanent dipoles, rod-like structure materials, and nanotubes.

5. The method according to claim 4, 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.

6. The method according to claim 1, wherein the porous matrix component is a pre-formed porous polymer matrix or is a polymer matrix, prepared by the PDLC-technique (polymer-dispersed liquid crystal-technique).