UV Stable and Low-Voltage Liquid Crystal Microdroplet Display

• US 20150275090A1
• Filed: 03/23/2015
• Published: 10/01/2015
• Est. Priority Date: 03/22/2014
• Status: Active Application

• Current Assignee: Jiansheng Wang
• Original Assignee: Jiansheng Wang
• Inventors: Wang, Jiansheng
• Application Number:
  US14/666,142
• Publication Number:
  US 20150275090A1
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 LCMD device comprises a polymer matrix and droplets of liquid crystal material dispersed in the polymer, wherein the polymer matrix or the liquid crystal includes a UV absorber. The LCMD material may be formed by phase separation with a dissolved framework polymer.

Claims

1. A Liquid Crystal Micro-Droplet (LCMD) panel, comprising:

a polymer matrix, wherein the polymer matrix contains a compound selected to absorb energy from ultraviolet radiation to go to an excited state and release heat upon return from the excited state to a ground state; and

droplets of a first liquid crystal material dispersed in the polymer matrix.

2. The panel of claim 1 further comprising a compound selected to absorb ultraviolet radiation in the droplets of liquid crystal.

3. The panel of claim 1 further comprising a film in contact with the polymer matrix, the film containing a compound selected to absorb ultraviolet radiation.

4. The panel of claim 2 wherein the selected compound forms a liquid crystal before it is added to the first liquid crystal material.

5. The panel of claim 2 wherein the first liquid crystal material is selected to absorb ultraviolet radiation.

6. The panel of claim 2 wherein the compound is benzophenone or a derivative of benzophenone or benzotriazole.

7. A liquid mixture for forming an LCMD material by phase separation comprising a compound selected for absorption of UV radiation.

8. The mixture of claim 7 wherein the compound comprises a conjugated system including two or more double bonds and an aliphatic hydrocarbon chain reacted with an aromatic group, the hydrocarbon chain having a number of carbon atoms in the range of 3 to 10.

9. The mixture of claim 7 wherein the compound is selected from derivatives of benzophenone or benzotriazole.

10. The mixture of claim 7 further comprising monomers or polymers selected to form a dissolved framework polymer before or during phase separation of the mixture.

11. The mixture of claim 10 wherein the monomers or polymers comprise bisphenol A or Capcure 3-800.

12. A method for making a Liquid Crystal Micro-Droplet material, comprising:

forming a liquid mixture comprising a compound selected for absorption of UV radiation and components selected to form liquid crystal microdroplets in a polymer matrix; and

causing a phase separation to form solid matrix containing micropdroplets of liquid crystal material.

13. The method of claim 12 further comprising adding to the mixture a monomer or polymer selected to at least partially polymerize before the polymer matrix becomes a solid and function as a dissolved framework polymer.

14. The method of claim 13 wherein the monomer or polymer is selected from bisphenol A or Capcure 3-800.

15. A Liquid Crystal Micro-Droplet (LCMD) film, comprising:

a polymer matrix; and

droplets of a liquid crystal material dispersed in the polymer matrix, wherein the panel is switched from a minimum value of transmittance to a maximum transmittance by application of an AC voltage of less than 30 volts.

16. A liquid crystal compound for forming a liquid crystal display, comprising:

a conjugated system for absorbing UV radiation to go to an excited state and releasing heat to return to a ground state; and

a flexible hydrocarbon chain having a number of carbon atoms in the range of 3 to 10.