Polarizing film, method for manufacturing same, polarizing plate, and display device

Patent metadata

Field	Value
Publication number	US-11634639-B2
Application number	US-201917059061-A
Country	US
Kind code	B2
Filing date	May 27, 2019
Priority date	Jun 1, 2018
Publication date	Apr 25, 2023
Grant date	Apr 25, 2023

Abstract

A polarizing film including a polarizer that is a cured product of a polymerizable liquid crystal composition is provided. The polymerizable liquid crystal composition contains both a polymerizable liquid crystal compound having at least one polymerizable group and a dichroic coloring matter. The polarizer is laminated on a surface, having a pore size of 0.45 nm to 0.57 nm, of a base material. The pore size is obtained by converting, into a diameter, an average free volume radius calculated by a positron lifetime measurement method in which the positron lifetime is measured by irradiating the surface with positrons with an injection energy of 3 kV.

First claim

The invention claimed is:

1. A polarizing film comprising a polarizer that is a cured product of a polymerizable liquid crystal composition containing both a polymerizable liquid crystal compound having at least one polymerizable group and a dichroic coloring matter, said polarizer being laminated on a surface, having a pore size of 0.53 nm to 0.57 nm, of a base material,
the pore size being obtained by converting, into a diameter, an average free volume radius calculated by a positron lifetime measurement method in which the positron lifetime is measured by irradiating the surface with positrons with an injection energy of 3 kV.

2. The polarizing film according to claim 1 , wherein an amount of change in haze, occurring when the polarizing film is immersed in warm water at 53° C. for 30 minutes, is 1.0 or less.

3. The polarizing film according to claim 1 , wherein the dichroic coloring matter is an azo coloring matter.

4. The polarizing film according to claim 1 , wherein the polymerizable liquid crystal compound exhibits smectic liquid crystallinity.

5. The polarizing film according to claim 1 , wherein the polarizer exhibits a Bragg peak in an X-ray analysis measurement.

6. The polarizing film according to claim 1 , wherein the surface, on which the polarizer is laminated, of the base material is made of a cured layer of a curable composition containing a radically polymerizable monomer.

7. The polarized light according to claim 1 , wherein the surface, on which the polarizer is laminated, of the base material is made of a cured layer of a curable composition containing a polymerizable monomer having a (meth)acryloyloxy group.

8. The polarizing film according to claim 1 , wherein the polarizer is laminated on the surface of the base material via a photo-orientation film.

9. A polarizing plate comprising the polarizing film according to claim 1 and a phase difference film which satisfies an expression (X):
100 nm≤ Re (550)≤180 nm  (X)

wherein, Re (550) represents an in-plane phase difference value at a wavelength of 550 nm, in which polarizing plate an angle between a slow axis of the phase difference film and an absorption axis of the polarizing film is substantially 45°.

10. The polarizing plate according to claim 9 , wherein
the phase difference film satisfies an expression (Y):
Re (450)/ Re (550)<1  (Y)

 wherein, Re(450) and Re(550) represent in-plane phase difference values at wavelengths of 450 nm and 550 nm, respectively.

11. The polarizing plate according to claim 9 , wherein the phase difference film is made of a polymer of a polymerizable liquid crystal compound.

12. A display device comprising the polarizing film according to claim 1 .

13. A method for manufacturing a polarizing film, comprising:
forming a coating film of a polymerizable liquid crystal composition containing both a polymerizable liquid crystal compound having at least one polymerizable group and a dichroic coloring matter on a surface, having a pore size of 0.53 nm to 0.57 nm, of a base material, the pore size being obtained by converting, into a diameter, an average free volume radius calculated by a positron lifetime measurement method in which the positron lifetime is measured by irradiating the surface with positrons with an injection energy of 3 kV;
removing a solvent from the coating film;
causing the polymerizable liquid crystal compound to make a phase transition to a smectic phase by heating the polymerizable liquid crystal compound to a temperature higher than or equal to a temperature at which the polymerizable liquid crystal compound makes a phase transition to a liquid phase and then by lowering the temperature; and
polymerizing the polymerizable liquid crystal compound while maintaining the smectic phase.

14. A display device comprising the polarizing plate according to claim 9 .

Assignees

• Sumitomo Chemical Co

Inventors

• Ota Yosuke
• Hatanaka Nobuyuki

Classifications

• H10K59/8791

  Arrangements for improving contrast, e.g. preventing reflection of ambient light · CPC title

• C09K19/3857 Primary

  containing at least one asymmetric carbon atom · CPC title

• G02B5/3016 Primary

  involving passive liquid crystal elements (optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528) · CPC title

• G02F1/1335

  Structural association of cells with optical devices, e.g. polarisers or reflectors · CPC title

• C09K2323/035

  Ester polymer, e.g. polycarbonate, polyacrylate or polyester · CPC title