Optical film, antireflection film, polarizing plate and image display device

Abstract

An optical film is provided and includes: a transparent support; and a light diffusion layer containing light-transmitting particles and a binder. The light diffusion layer has an average thickness of from 7.5 to 30 μm, and the average thickness of the light diffusion layer is from 1.4 to 3.5 times as large as an average particle diameter of the light-transmitting particles.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the invention will appear more fully upon consideration of the exemplary embodiments of the invention, which are schematically set forth in the drawings, in which:

FIG. 1 is a schematic view showing a cross section of a film which is an exemplary embodiment of the invention;

FIG. 2 is a schematic view showing a cross section of a film which is an exemplary embodiment of the invention;

FIG. 3 is a schematic view showing a cross section of a film which is an exemplary embodiment of the invention;

FIG. 4 is a schematic view showing a cross section of a film which is an exemplary embodiment of the invention;

FIG. 5 is a schematic view showing a cross section of a film which is an exemplary embodiment of the invention;

FIG. 6 is a view showing a cross section of a coater 10 having a slot die 13 suitable for an exemplary embodiment of the invention;

FIG. 7A shows the cross section of the slot die 13, while FIG. 7B shows a cross section of a slot die 30 in the background art.

FIG. 8 is a perspective view showing a slot die and its vicinity in a coating step in a method for producing a film according to an exemplary embodiment of the invention;

FIG. 9 shows a cross section of a vacuum chamber 40 and a web W (wherein a back plate 40a is united together the chamber 40);

FIG. 10 is a diagram schematically showing the relationship among the thickness of a light diffusion layer, the average particle diameter of light-transmitting particles and antiglare properties.

FIG. 11 is a diagram schematically showing localization of particles with respect to the film thickness.

Claims

1. An optical film comprising: a transparent support; and a light diffusion layer containing light-transmitting particles and a binder, wherein the light diffusion layer has an average thickness of from 7.5 to 30 μm, and the average thickness of the light diffusion layer is from 1.4 to 3.5 times as large as an average particle diameter of the light-transmitting particles.

2. The optical film of claim 1, wherein the average particle diameter of the light-transmitting particles is from 3 to 12 μm.

3. The optical film of claim 1, wherein the light-transmitting particles has a CV value of not more than 15%.

4. The optical film of claim 1, wherein a difference between a refractive index of the light-transmitting particles and a refractive index of the light diffusion layer excluding the light-transmitting particles is from 0.001 to 0.03.

5. The optical film of claim 1, wherein the light diffusion layer contains the light-transmitting particles in an amount of from 5 to 40% by wight based on the total solid contents of the light diffusion layer.

6. The optical film of claim 1, wherein the binder comprises a trifunctional or higher (meth)acrylate monomer as a main component, and the light-transmitting particles polymer particles comprising crosslinked poly((meth)acrylate) having an acryl content of from 50 to 100% by weight.

7. The optical film of claim 1, wherein the light diffusion layer has a pencil hardness of from 4 H to 9 H.

8. The optical film of claim 1, wherein the light diffusion layer has an internal haze of from 0 to 60% and a surface haze of from 0.3 to 20%.

9. The optical film of claim 1, wherein the light diffusion layer has an arithmetic average roughness Ra of from 0.03 to 0.30 μm and an average peak-valley interval Sm of from 40 to 200 μm.

10. The optical film of claim 1, wherein the light-transmitting particles has a compression strength of from 4 to 10 kgf/mm2.

11. The optical film of claim 1, further comprising a hard coat layer stacked on the light diffusion layer in a manner that changes an arithmetic average roughness Ra of a surface of the optical film.

12. An antireflective film comprising: an optical film of claim 1; and a low refractive index layer as an uppermost layer of the antireflective film, the low refractive index layer having a lower refractive index than the transparent support.

13. A polarizing plate comprising: a polarizer; and two protective films, wherein at least one of the two protective films is an optical film of claim 1.

14. An image display device comprising an optical film of claim 1, wherein the light diffusion layer is provided on a viewing side of the image display device.