Optical film, polarizing plate, liquid crystal panel, and image display apparatus

Patent metadata

Field	Value
Publication number	US-10295706-B2
Application number	US-201314396882-A
Country	US
Kind code	B2
Filing date	Apr 24, 2013
Priority date	May 9, 2012
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

Provided are: an optical film, wherein interference fringes can be suppressed from being generated, cloudiness is not observed, and a manufacture cost can be reduced. In accordance with one aspect of the present invention, there is provided an optical film 10 including a functional layer 12 , wherein the functional layer 12 has a concavo-convex surface 12 A; and in a state in which the concavo-convex surface 12 A is irradiated with parallel light travelling in a direction sloped at 10° with respect to a normal direction N of the optical film 10 , in an angle distribution of reflected light intensities measured in a plane including both directions of the normal direction N and the travelling direction T of the parallel light, a value obtained by subtracting ½ angle width from 1/100 angle width is 0.7° or more and 1.4° or less.

First claim

The invention claimed is:

1. An optical film comprising: a light transmissive base material; and a functional layer disposed on the light transmissive base material, wherein:
the functional layer has a concavo-convex surface forming a surface of the optical film;
the functional layer comprises a hard coat layer having a concavo-convex surface, and a low refractive index layer conformally disposed on the concavo-convex surface of the hard coat layer and having a lower refractive index than that of the hard coat layer;
the hard coat layer comprises a binder resin and inorganic oxide fine particles having an average primary particle diameter of 1 nm or more and 100 nm or less;
the hard coat layer does not comprise any particles other than the inorganic oxide fine particles and aggregates thereof;
a root mean square slope RΔq of a roughness curve on the concavo-convex surface forming the surface of the optical film is 0.0005 or more and 0.0026 or less;
an average spacing Sm of concavities and convexities that constitute the concavo-convex surface forming the surface of the optical film is 0.20 mm or more and 0.60 mm or less;
in a state in which the concavo-convex surface forming the surface of the optical film is irradiated with parallel light travelling in a direction sloped at 10° with respect to a normal direction of the optical film, in an angle distribution of a reflected light intensity measured in a plane including both directions of the normal direction and the travelling direction of the parallel light, using a detector with a light receiving diaphragm of 4.0, a value obtained by subtracting a width of an angle region, in which a reflected light intensity that is not less than ½ of a maximum reflected light intensity is measured, from a width of an angle region, in which a reflected light intensity that is not less than 1/100 of the maximum reflected light intensity is measured, is 0.7° or more and 1.4° or less; and
the detector is GP-200 manufactured by MURAKAMI COLOR RESEARCH LABORATORY.

2. The optical film according to claim 1 , wherein a surface of the low refractive index layer is the concavo-convex surface forming the surface of the optical film.

3. The optical film according to claim 1 , wherein the average spacing Sm is 0.22 mm or more and 0.60 mm or less.

4. The optical film according to claim 1 , wherein the average spacing Sm is 0.27 mm or more and 0.60 mm or less.

5. The optical film according to claim 1 , wherein an arithmetic mean roughness Ra of concavities and convexities that constitute the concavo-convex surface forming the surface of the optical film is 0.02 μm or more and 0.10 μm or less.

6. The optical film according to claim 1 , wherein a maximum height roughness Ry of concavities and convexities that constitute the concavo-convex surface forming the surface of the optical film is 0.20 μm or more and 0.60 μm or less.

7. The optical film according to claim 1 , wherein a ten-point average roughness Rz of concavities and convexities that constitute the concavo-convex surface forming the surface of the optical film is 0.15 μm or more and 0.50 μm or less.

8. The optical film according to claim 1 , wherein an average slope angle θa of concavities and convexities that constitute the concavo-convex surface forming the surface of the optical film is 0.01° or more and 0.08° or less.

9. A polarizing plate comprising:
the optical film according to claim 1 ; and
a polarizing element formed on a surface of the light transmissive base material of the optical film, the surface being opposite to the other surface thereof on which the functional layer is formed.

10. A liquid-crystal display panel comprising the optical film according to claim 1 .

11. An image display apparatus comprising the optical film according to claim 1 .

12. An optical film comprising: a light transmissive base material; and a functional layer disposed on the light transmissive base material, wherein:
the functional layer has a concavo-convex surface forming a surface of the optical film;
the functional layer comprises a hard coat layer having a concavo-convex surface, and a low refractive index layer disposed on the concavo-convex surface of the hard coat layer and having a lower refractive index than that of the hard coat layer;
the hard coat layer comprises a binder resin and inorganic oxide fine particles having an average primary particle diameter of 1 nm or more and 100 nm or less;
the hard coat layer does not comprise any particles other than the inorganic oxide fine particles and aggregates thereof;
a root mean square slope RΔq of a roughness curve on the concavo-convex surface forming the surface of the optical film is 0.0005 or more and 0.0026 or less;
an average spacing Sm of concavities and convexities that constitute the concavo-convex surface forming the surface of the optical film is 0.20 mm or more and 0.60 mm or less;
a reflection clarity of the concavo-convex surface forming the surface of the optical film, measured using a 0.5 mm-width optical comb, is 90% or less, and a reflection clarity of the concavo-convex surface forming the surface of the optical film, measured using a 2.0 mm-width optical comb, is 80% or more; and
the optical film has a transmission image clarity of 75% or more and 95% or less with a 0.125 mm-width comb and a transmission image clarity of 95% or more with a 2.0 mm-width comb.

13. The optical film according to claim 12 , wherein a surface of the low refractive index layer is the concavo-convex surface forming the surface of the optical film.

14. The optical film according to claim 12 , wherein the average spacing Sm is 0.22 mm or more and 0.60 mm or less.

15. The optical film according to claim 12 , wherein the average spacing Sm is 0.27 mm or more and 0.60 mm or less.

16. The optical film according to claim 12 , wherein an arithmetic mean roughness Ra of concavities and convexities that constitute the concavo-convex surface forming the surface of the optical film is 0.02 μm or more and 0.10 μm or less.

17. The optical film according to claim 12 , wherein a maximum height roughness Ry of concavities and convexities that constitute the concavo-convex surface forming the surface of the optical film is 0.20 μm or more and 0.60 μm or less.

18. The optical film according to claim 12 , wherein a ten-point average roughness Rz of concavities and convexities that constitute the concavo-convex surface forming the surface of the optical film is 0.15 μM or more and 0.50 μm or less.

19. The optical film according to claim 12 , wherein an average slope angle θa of concavities and convexities that constitute the concavo-convex surface forming the surface of the optical film is 0.01° or more and 0.08° or less.

20. A polarizing plate comprising:
the optical film according to claim 12 ; and
a polarizing element formed on a surface of the light transmissive base material of the optical film, the surface being opposite to the other surface thereof on which the functional layer is formed.

21. A liquid-crystal display panel comprising the optical film according to claim 12 .

22. An image display apparatus comprising the optical film according to claim 12 .

Assignees

• Dainippon Printing Co Ltd

Inventors

• Ogumi Shoichiro
• Eguchi Junya
• Furui Gen
• Minakoshi Seika
• Iwata Yukimitsu

Classifications

• G02F2201/38

  Anti-reflection arrangements · CPC title

• G02B1/14

  Protective coatings, e.g. hard coatings · CPC title

• G02F1/133528

  Polarisers · CPC title

• G02B5/0242

  by means of dispersed particles · CPC title

• G02B5/0221

  the surface having an irregular structure (G02B5/0226 takes precedence) · CPC title