Liquid crystal composition, patterned phase delay film and preparation method thereof, and display device

Patent metadata

Field	Value
Publication number	US-10059879-B2
Application number	US-201514894798-A
Country	US
Kind code	B2
Filing date	Jun 18, 2015
Priority date	Dec 15, 2014
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

A liquid crystal composition comprises a photo-polymerizable liquid crystal mixture and a heat-polymerizable liquid crystal mixture, and the two mixtures have opposite rotatory directions. A patterned phase delay film is prepared from the liquid crystal composition. A display device comprises the phase delay film. The preparation of the patterned phase-delay film can be implemented by a two-step polymerization process including UV-polymerization and heat-polymerization. The process is simple and the costs are low.

First claim

What is claimed is:

1. A method for preparing a patterned phase delay film comprising the steps of:
injecting a liquid crystal composition into a liquid crystal cell;
irradiating the liquid crystal cell partially covered with a photo mask with UV light to complete UV-polymerization; and
heating the liquid crystal cell to complete heat-polymerization,
wherein the liquid crystal composition comprises a photo-polymerizable liquid crystal mixture and a heat-polymerizable liquid crystal mixture, wherein the photo-polymerizable liquid crystal mixture and heat-polymerizable liquid crystal mixture have opposite rotatory directions,
wherein the photo-polymerizable liquid crystal mixture comprises a small molecule nematic liquid crystal, a photo-polymerizable monomer, a UV-absorbing dye, a chiral additive, and a photoinitiator; and
wherein the heat-polymerizable liquid crystal mixture comprises a small molecule nematic liquid crystal, a heat-polymerizable monomer, a curing agent, and a chiral additive.

2. The method according to claim 1 , wherein a condition for the UV-polymerization is UV light intensity being 0.001-100 mW/cm 2 and irradiation time being 5-240 min.

3. The method according to claim 1 , wherein a condition for the heat-polymerization is temperature being 30-120° C. and heating time being 20-60 min.

4. The method of claim 1 , wherein the liquid crystal composition has a mass ratio of the photo-polymerizable liquid crystal mixture to the heat-polymerizable liquid crystal mixture of 1: (0.4-3).

5. The method of claim 1 , wherein the photo-polymerizable liquid crystal mixture comprises, by mass percentage, 28-69.5% of the small molecule nematic liquid crystal, 15-40% of the photo-polymerizable monomer, 2-15% of the UV-absorbing dye, 0.1-25% of chiral additive, and 0.5-5% of photoinitiator.

6. The method of claim 1 , wherein the photo-polymerizable monomer is selected from the group consisting of:

7. The method of claim 1 , wherein the UV-absorbing dye comprises:

8. The method of claim 1 , wherein the photoinitiator comprises:

9. The method of claim 1 , wherein the heat-polymerizable liquid crystal mixture comprises, by mass percentage, 35-73% of the small molecule nematic liquid crystal, 10-20% of the heat-polymerizable monomer, 12-20% of the curing agent and 5-25% of the chiral additive.

10. The method of claim 1 , wherein the heat-polymerizable monomer comprises
a bisphenol F epoxy resin which has the following molecular formula:

or
a polyethylene glycol bisglycidyl ether which has the following molecular formula:

11. The method of claim 1 , wherein the curing agent comprises:
1,8-diamino-3,6-dioxaoctane which has the following molecular formula:

or
4,4′-diaminodicyclohexylmethane which has the following molecular formula:

12. The method of claim 1 , wherein the chiral additive is selected from the group consisting of

13. A display device comprising a patterned phase-delay film,
wherein the patterned phase delay film is prepared from a liquid crystal composition, and
wherein the liquid crystal composition comprises a photo-polymerizable liquid crystal mixture and a heat-polymerizable liquid crystal mixture, wherein the photo-polymerizable liquid crystal mixture and heat-polymerizable liquid crystal mixture have opposite rotatory directions,
wherein the photo-polymerizable liquid crystal mixture comprises a small molecule nematic liquid crystal, a photo-polymerizable monomer, a UV-absorbing dye, a chiral additive and a photoinitiator; and
wherein the heat-polymerizable liquid crystal mixture comprises a small molecule nematic liquid crystal, a heat-polymerizable monomer, a curing agent and a chiral additive.

14. The display device according to claim 13 , wherein the liquid crystal composition has a mass ratio of the photo-polymerizable liquid crystal mixture to the heat-polymerizable liquid crystal mixture of 1: (0.4-3).

15. The display device according to claim 13 , wherein the photo-polymerizable liquid crystal mixture comprises, by mass percentage, 28-69.5% of the small molecule nematic liquid crystal, 15-40% of the photo-polymerizable monomer, 2-15% of the UV-absorbing dye, 0.1-25% of the chiral additive and 0.5-5% of the photoinitiator.

16. The display device according to claim 13 , wherein the heat-polymerizable liquid crystal mixture comprises, by mass percentage, 35-73% of the small molecule nematic liquid crystal, 10-20% of the heat-polymerizable monomer, 12-20% of the curing agent and 5-25% of the chiral additive.

Assignees

• Boe Technology Group Co Ltd
• Beijing Boe Display Tech Co

Inventors

• Wang Feifei
• Shao Xibin
• Wang Dan
• Lee Seungmin
• Zhang Honglin
• Zhao Hebin
• Dong Ting
• Qu Yingying

Classifications

• C09K19/3852

  Poly(meth)acrylate derivatives · CPC title

• C09K2219/03

  in the form of films, e.g. films after polymerisation of LC precursor · CPC title

• C09K2019/2042

  Ph-Ph-COO-Ph · CPC title

• C09K19/54

  Additives having no specific mesophase {characterised by their chemical composition} · CPC title

• C09K19/2007

  the chain containing -COO- or -OCO- groups · CPC title