Polarizing plate and polarizing plate assembly

Patent metadata

Field	Value
Publication number	US-11009639-B2
Application number	US-201816189231-A
Country	US
Kind code	B2
Filing date	Nov 13, 2018
Priority date	Oct 30, 2015
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

An object of the present invention is to solve the problems which can be peculiarly generated in a coating-type optical film, and provide an optical film which hardly causes deterioration in optical performance with time, a display device equipped with the optical film, and a process for producing the optical film, and there is provided a polarizing plate having a diffusion preventing layer A having the thickness of 0.05 μm to 3 μm, a polarizing film comprising a polymer of a polymerizable liquid crystal and a dichroic coloring matter, and a diffusion preventing layer B having the thickness of 0.05 μm to 3 μm, in this order.

First claim

What is claimed is:

1. A polarizing plate comprising:
a diffusion preventing layer A having the thickness of 20 μm or less;
a polarizing film comprising a polymer of a polymerizable liquid crystal and an azo coloring matter, the polarizing film being formed from a composition comprising the polymerizable liquid crystal and the azo coloring matter, a content of the polymerizable liquid crystal in the composition being 70 to 99.5 parts by mass based on 100 parts by mass of the solid content of the composition; and
a diffusion preventing layer B having a thickness of 20 μm or less, in this order.

2. The polarizing plate according to claim 1 , wherein the thickness of each of the diffusion preventing layers A and B is in a range of 0.05 μm to 3 μm.

3. The polarizing plate according to claim 1 , wherein at least one of the diffusion preventing layers A and B comprises a water-soluble polymer.

4. The polarizing plate according to claim 1 , wherein the polymerizable liquid crystal is a thermotropic liquid crystal compound exhibiting a smectic phase.

5. The polarizing plate according to claim 4 , wherein the polarizing film comprises a polymer of a polymerizable liquid crystal obtained by polymerization in a state of a smectic phase.

6. A polarizing plate assembly comprising a polarizing plate according to claim 1 and an adhesive layer, wherein the polarizing plate has the adhesive layer on a side of the diffusion preventing layer A or the diffusion preventing layer B, which is opposite to the polarizing film.

7. The polarizing plate according to claim 1 , wherein the thickness of at least one of the diffusion preventing layers A and B is in a range of 0.5 μm to 3 μm.

8. A polarizing plate assembly comprising a polarizing plate according to claim 1 and a front plate arranged on a side of the diffusion preventing layer A or the diffusion preventing layer B, which is opposite to the polarizing film.

9. The polarizing plate assembly according to claim 6 , further comprising a front plate arranged on a side of the adhesive layer which is opposite to the diffusion preventing layer A or the diffusion preventing layer B.

10. The polarizing plate assembly according to claim 8 , wherein the front plate has on at least one side thereof one or more patterning layers selected from the group consisting of the following (A) to (D):
(A) Color filter layer;
(B) Thin-film transistor (TFT) layer;
(C) Transparent electrode layer; and
(D) Decorating layer.

11. The polarizing plate with a front plate according to claim 9 , wherein the front plate has on at least one side thereof one or more patterning layers selected from the group consisting of the following (A) to (D):
(A) Color filter layer;
(B) Thin-film transistor (TFT) layer;
(C) Transparent electrode layer; and
(D) Decorating layer.

12. An elliptic polarizing plate assembly comprising a polarizing plate according to claim 1 and a phase difference film on a side of the diffusion preventing layer A or the diffusion preventing layer B, which is opposite to the polarizing film.

13. An elliptic polarizing plate assembly comprising a polarizing plate according to claim 6 and a phase difference film on a side of the adhesive layer which is opposite to the diffusion preventing layer A or the diffusion preventing layer B.

14. An elliptic polarizing plate assembly comprising a polarizing plate according to claim 8 and a phase difference film on a side of the diffusion preventing layer A or the diffusion preventing layer B, which is opposite to the polarizing film.

15. An elliptic polarizing plate assembly comprising a polarizing plate according to claim 9 and a phase difference film on a side of the diffusion preventing layer A or the diffusion preventing layer B, which is opposite to the polarizing film.

16. The elliptic polarizing plate according to claim 12 , wherein the phase difference film satisfies the following expressions (1), (2) and (3):
Re (450)/ Re (550)≤1.00  (1)

1.00 ≤Re (650)/ Re (550)  (2)

120 ≤Re (550)≤180  (3),

wherein Re(450), Re(550) and Re(650) represent in-plane retardation at wavelengths of 450 nm, 550 nm and 650 nm, respectively.

17. The elliptic polarizing plate according to claim 13 , wherein the phase difference film satisfies the following expressions (1), (2) and (3):
Re (450)/ Re (550)≤1.00  (1)

1.00 ≤Re (650)/ Re (550)  (2)

120 ≤Re (550)≤180  (3),

wherein Re(450), Re(550) and Re(650) represent in-plane retardation at wavelengths of 450 nm, 550 nm and 650 nm, respectively.

18. An organic electroluminescence display device equipped with a polarizing plate according to claim 1 .

19. A liquid crystal display device equipped with a polarizing plate according to claim 1 .

20. A process for producing a polarizing plate assembly having a front plate, the process comprising a step of transferring a polarizing plate according to claim 1 onto the front plate.

21. A process for producing a polarizing plate according to claim 1 , the process comprising the following steps (a) to (c):
(a) a step of forming a diffusion preventing layer A on a substrate;
(b) a step of forming a polarizing film on the diffusion preventing layer A; and
(c) a step of forming a diffusion preventing layer B on the polarizing film.

22. A process for producing a polarizing plate according to claim 1 , the process comprising the following steps (a) to (e):
(a) a step of forming a diffusion preventing layer A on a substrate;
(b) a step of forming a polarizing film on the diffusion preventing layer A;
(c) a step of coating a diffusion preventing layer composition for forming a diffusion preventing layer B on the polarizing film or on an adherend;
(d) a step of sticking the polarizing film and the adherend via the diffusion preventing layer composition; and
(e) a step of forming the diffusion preventing layer B by curing the diffusion preventing layer composition.

23. A process for producing a polarizing plate according to claim 1 , the process comprising the following steps (a) to (h):
(a) a step of forming a polarizing film on a substrate;
(b) a step of coating a first diffusion preventing layer composition for forming a diffusion preventing layer B on the polarizing film or on a first adherend;
(c) a step of sticking the polarizing film and the first adherend via the first diffusion preventing layer composition;
(d) a step of forming the diffusion preventing layer B by curing the first diffusion preventing layer composition;
(e) a step of removing the substrate;
(f) a step of coating a second diffusion preventing layer composition for forming a diffusion preventing layer A on a surface of the polarizing film, from which the substrate has been removed, or on a second adherend;
(g) a step of sticking the surface of the polarizing film, from which the substrate has been removed, and the second adherend via the second diffusion preventing layer composition; and
(h) a step of forming the diffusion preventing layer A by curing the second diffusion preventing layer composition.

Assignees

• Sumitomo Chemical Co

Inventors

• Hatanaka Nobuyuki
• Ota Yosuke

Classifications

• G02B5/305 Primary

  including organic materials, e.g. polymeric layers · CPC title

• B32B37/12

  characterised by using adhesives · CPC title

• G02F1/133528

  Polarisers · CPC title

• C09J7/20

  characterised by their carriers · CPC title

• G02B1/04

  made of organic materials, e.g. plastics (G02B1/08 takes precedence) · CPC title