Optically absorptive anisotropic film, three-dimensional optically absorptive anisotropic film and method for producing the same

Patent metadata

Field	Value
Publication number	US-9421572-B2
Application number	US-201514749935-A
Country	US
Kind code	B2
Filing date	Jun 25, 2015
Priority date	Jun 25, 2014
Publication date	Aug 23, 2016
Grant date	Aug 23, 2016

Abstract

An optically absorptive anisotropic film includes a dichroic dye. The light absorbances of the film satisfy the formulas (1), (2) and (3):

Az >( Ax+Ay )/2  (1)

Ax ( z =60)/ Ax >5  (2)

Ay ( z =60)/ Ay >5  (3)

wherein Ax, Ay, Az, Ax (z=60) and Ay (z=60) are absorbances at a local maximum absorption wavelength of the dichroic dye; Ax, Ay and Az represent an absorbance of linearly polarized light vibrating in the direction of the x-axis, y-axis and z-axis, respectively; Ax (z=60) represents an absorbance of the linearly polarized light vibrating in the direction of the x-axis in the state of the film rotated by 60° around the y-axis; and Ay (z=60) represents an absorbance of the linearly polarized light vibrating in the direction of the y-axis in the state the film rotated by 60° around the x-axis.

First claim

What is claimed is:

1. An optically absorptive anisotropic film comprising a dichroic dye and a liquid crystalline compound, wherein,
when an arbitrary direction in the film plane is defined as an x-axis, the axis orthogonal to the x-axis in the film plane is defined as a y-axis and the axis orthogonal to the x-axis and the y-axis is defined as a z-axis, the light absorbances of the film satisfy the formulas (1), (2) and (3):
Az >( Ax+Ay )/2  (1)

Ax ( z= 60)/ Ax >5  (2)

Ay ( z= 60)/ Ay >5  (3)

wherein Ax, Ay, Az, Ax (z=60) and Ay (z=60) are absorbances at a local maximum absorption wavelength of the dichroic dye contained in the film;
Ax represents an absorbance of linearly polarized light vibrating in the direction of the x-axis;
Ay represents an absorbance of linearly polarized light vibrating in the direction of the y-axis;
Az represents an absorbance of linearly polarized light vibrating in the direction of the z-axis;
Ax (z=60) represents an absorbance of the linearly polarized light vibrating in the direction of the x-axis in the state of the film rotated by 60° around the y-axis;
Ay (z=60) represents an absorbance of the linearly polarized light vibrating in the direction of the y-axis in the state the film rotated by 600 around the x-axis.

2. The optically absorptive anisotropic film according to claim 1 , wherein the liquid crystalline compound forms a smetic liquid crystal phase.

3. The optically absorptive anisotropic film according to claim 1 , wherein the liquid crystalline compound forms a high order smectic liquid crystal phase.

4. The optically absorptive anisotropic film according to claim 1 , wherein the optically absorptive anisotropic film exhibits a Bragg peak in x-ray diffraction measurement.

5. The optically absorptive anisotropic film according to claim 1 , wherein the local maximum absorption wavelength of the dichroic dye contained in the optily absorptive anisotropic film is in a wavelength range of 500 to 600 nm.

6. The optically absorptive anisotropic film according to claim 1 , wherein the optically absorptive anisotropic film satisfies the formulas (4) and (5),
Ax ( z 60)/ Ax> 10  (4)

Ay 1 z− 60)/ Ay> 10  (5).

7. The optically absorptive anisotropic film according to claim 1 , wherein the optically absorptive anisotropic film comprising at least three dichroic dyes differing in a local maximum absorption wavelength.

8. The optically absorptive anisotropic film according to claim 1 , wherein the optically absorptive anisotropic film has a thickness of 5 μm or less.

9. An optical film comprising the optically absorptive anisotropic film according to claim 1 and a substrate.

10. The optical film according to claim 9 , wherein the optical film has no orientation film between the optically absorptive anisotropic film and the substrate.

11. A method for producing the optical film according to claim 9 , the method comprising the following steps of (1), (2), (3) and (4) to be performed in this order:
(1) a step of forming a coating layer by coating a substrate with a composition comprising the liquid crystalline compound, the dichroic dye and a solvent;
(2) a step of forming a dried layer by removing the sol vent from the coating layer;
(3) a step of developing a liquid crystal phase by cooling the dried layer; and
(4) a step of curing the liquid crystalline compound by applying active energy rays.

12. The method according to claim 11 , wherein an elongated film is used as the substrate and the optical film is produced continuously.

13. A three-dimensional optically absorptive anisotropic film in which the optically absorptive anisotropic film according to claim 1 is laminated together with a horizontal polarizing film, wherein,
when an absorption axis of the horizontal polarizing film is defined as an x′-axis, a transmission axis of the horizontal polarizing film is defined as a y′-axis and the axis orthogonal to the x′-axis and the y′-axis is defined as a z′-axis, the three-dimensional optically absorptive anisotropic film satisfies the formula (6):
Ax′>Az′>Ay′   (6)

wherein Ax′, Ay′ and Az′ are an absorbances at a local maximum absorption wavelength of the dichroic dye contained in the optically absorptive anisotropic film;
Ax′ represents an absorbance of linearly polarized light vibrating in the direction of the x′-axis;
Ay′ represents an absorbance of linearly polarized light vibrating in the direction of the y′-axis; and
Az′ represents an absorbance of linearly polarized light vibrating in the direction of the z′-axis.

14. The three-dimensional optically absorptive anisotropic film according to claim 13 , wherein the horizontal polarizing film comprises a polyvinyl alcohol and a dichroic dye.

15. The three-dimensional optically absorptive anisotropic film according to claim 13 , wherein the horizontal polarizing film comprises a dichroic dye and a liquid crystalline compound, or comprises a dichroic dye having liquid crystalline properties.

16. The three-dimensional optically absorptive anisotropic film according to claim 13 , wherein the optically absorptive anisotropic film is laminated on the horizontal polarizing film via a pressure-sensitive adhesive or an adhesive.

Assignees

• Sumitomo Chemical Co

Inventors

• Hatanaka Nobuyuki

Classifications

• G02B5/3016

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

• G02B5/223 Primary

  containing organic substances, e.g. dyes, inks or pigments · CPC title

• G02B1/04

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

• B05D3/0272 Primary

  with ovens · CPC title

• C08L29/04

  Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids · CPC title