Diffusion film comprising transparent substrate and diffusion layer

Abstract

An anti-reflection film which includes a transparent substrate, a diffusion layer and a low refractive index layer in this order, wherein the diffusion layer shows such a scattered light profile measured by a goniophotometer that a ratio of an intensity of scattered light at an angle of 30° to an intensity of transmitted light at an angle of 0° is 0.01 to 0.2%, and wherein an average mirror reflectance of incident light at an angle of 5° is not more than 2.5% in the wavelength region of 450 to 650 nm.

1 . An anti-reflection film which comprises a transparent substrate, a diffusion layer and a low refractive index layer in this order, wherein the diffusion layer shows such a scattered light profile measured by a goniophotometer that a ratio of an intensity of scattered light at an angle of 30° to an intensity of transmitted light at an angle of 0° is 0.01 to 0.2%, and wherein an average mirror reflectance of incident light at an angle of 5° is not more than 2.5% in the wavelength region of 450 to 650 nm.  
   
   
       2 . A polarizing plate comprising a pair of protective films and a polarizing membrane provided between the protective films, wherein one of the protective films is the anti-reflection film defined in  claim 1 .  
   
   
       3 . The anti-reflection film as claimed in  claim 1 , wherein the diffusion layer shows such a scattered light profile measured by a goniophotometer that a ratio of an intensity of scattered light at an angle of 60° to an intensity of transmitted light at an angle of 0° is not more than 0.02%.  
   
   
       4 . The anti-reflection film as claimed in  claim 1 , wherein the diffusion layer has a total haze value in the range of 40 to 90%.  
   
   
       5 . The anti-reflection film as claimed in  claim 1 , wherein the diffusion layer has an internal diffusing haze value in the range of 30 to 80%.  
   
   
       6 . The anti-reflection film as claimed in  claim 1 , wherein the diffusion layer has a haze value measured at an angle of 30° in the range of 30 to 95%.  
   
   
       7 . The anti-reflection film as claimed in  claim 1 , wherein the diffusion layer comprises a transparent resin and transparent fine particles, said transparent fine particles having a refractive index different from a refractive index of said transparent resin.  
   
   
       8 . The anti-reflection film as defined in  claim 7 , wherein the difference in the refractive index between the transparent resin and the transparent fine particles is in the range of 0.02 to 0.20.  
   
   
       9 . The anti-reflection film as defined in  claim 7 , wherein the fine particles comprise relatively small particles having a particle size in the range of 0.5 to 2.0 μm and relatively large particles having a particle size in the range of 2.5 to 5.0 μm.  
   
   
       10 . The anti-reflection film as defined in  claim 1 , wherein the diffusion layer has such a rough surface that an average angle in an angular distribution from the surface of the layer is in the range of 1.5 to 5°.  
   
   
       11 . The anti-reflection film as defined in  claim 1 , wherein the diffusion layer has such a rough surface that the maximum peak angle in an angular distribution from the surface of the layer is in the range of 0.4 to 1.4°.  
   
   
       12 . The anti-reflection film as defined in  claim 1 , wherein the diffusion layer has such a rough surface that a surface roughness is in the range of 0.05 to 0.18 μm.  
   
   
       13 . The anti-reflection film as defined in  claim 1 , wherein the transparent substrate is an optically anisotropic polymer film.  
   
   
       14 . The anti-reflection film as defined in  claim 13 , wherein the optically anisotropic polymer film has a Re retardation value in the range of 0 to 200 nm and a Rth retardation value in the range of 70 to 500 nm.  
   
   
       15 . The polarizing plate as defined in  claim 2 , wherein the polarizing plate further comprises an optically anisotropic layer formed of a liquid crystal compound, and the plate comprises the anti-reflection film, the polarizing membrane and the optically anisotropic layer in this order.  
   
   
       16 . The polarizing plate as defined in  claim 15 , wherein the liquid crystal compound is a discotic compound.  
   
   
       17 . An image display device having a display surface covered with the anti-reflection film defined in  claim 1.