Multi-layered light diffusion plate and liquid crystal display device comprising the same

Abstract

Disclosed herein is a multi-layered light diffusion plate, in which the multi-layered light diffusion plate is manufactured by coextruding a transparent layer comprising an amorphous transparent thermoplastic resin and a light diffusion layer comprising an amorphous transparent thermoplastic resin and transparent particles, so that the manufacturing process thereof is simple and efficient, and which has excellent light transmissivity and light diffusivity, high brightness, and high brightness uniformity, thereby improving viewing angle characteristics, and to a liquid crystal display device comprising the same.

1 . A multi-layered light diffusion plate comprising a coextruded transparent layer, and a light diffusion layer, wherein the transparent layer comprises an amorphous transparent thermoplastic resin and the light diffusion layer comprises an amorphous transparent thermoplastic resin and transparent particles. 
     
     
         2 . The multi-layered light diffusion plate of  claim 1 , wherein the amorphous transparent thermoplastic resin is selected from the group consisting of polyalkyl(meth)acrylate, an alkyl(meth)acrylate-styrene copolymer, polycarbonate, polyvinylchloride, a styrene-acrylonitrile copolymer, a styrene-maleic anhydride copolymer, a styrene-maleic anhydride derivative copolymer, a cycloolefin copolymer, polyacrylonitrile, polystyrene, polysulfone, polyethersulfone, polyarylate and a mixture thereof. 
     
     
         3 . The multi-layered light diffusion plate of  claim 2 , wherein the amorphous transparent thermoplastic resin is selected from the group consisting of polymethyl(meth)acrylate, a methyl(meth)acrylate-styrene copolymer, polycarbonate, polystyrene and a mixture thereof. 
     
     
         4 . The multi-layered light diffusion plate of  claim 1 , wherein the transparent particles are inorganic particles, organic particles or a mixture thereof. 
     
     
         5 . The multi-layered light diffusion plate of  claim 4 , wherein the organic particles are produced using one or more selected from the group consisting of a polymethyl(meth)acrylate resin, a methyl(meth)acrylate-styrene copolymer resin, a polystyrene resin and a silicon resin. 
     
     
         6 . The multi-layered light diffusion plate of  claim 4 , wherein the organic particles are partially cross-linked. 
     
     
         7 . The multi-layered light diffusion plate of  claim 4 , wherein the inorganic particles are one or more selected from the group consisting of calcium carbonate, barium sulfate, titanium oxide, aluminum hydroxide, silica, a glass bead, talc, mica, white carbon, magnesium oxide, and zinc oxide. 
     
     
         8 . The multi-layered light diffusion plate of  claim 1 , wherein the transparent particles have an average particle size of between 0.5 μm and 50 μm. 
     
     
         9 . The multi-layered light diffusion plate of  claim 1 , wherein the light diffusion layer comprises:
 from 80 to 99.9 parts by weight of an amorphous transparent thermoplastic resin; and   from 0.1 to 20 parts by weight of transparent particles.   
     
     
         10 . The multi-layered light diffusion plate of  claim 1 , wherein the transparent layer has a thickness of between 0.95 mm and 3.0 mm. 
     
     
         11 . The multi-layered light diffusion plate of  claim 1 , wherein the light diffusion layer has a thickness of between 50 μm to 500 μm. 
     
     
         12 . The multi-layered light diffusion plate of  claim 1 , wherein the multi-layered light diffusion plate is a two-layered structure or a three-layered structure. 
     
     
         13 . The multi-layered light diffusion plate of  claim 12 , wherein the three-layered structure comprises:
 an intermediate layer formed of the transparent layer;   an uppermost layer formed of the light diffusion layer; and   a lowermost layer formed of the light diffusion layer.   
     
     
         14 . The multi-layered light diffusion plate of  claim 1 , wherein the light diffusion plate has a total light transmissivity of 60% or more. 
     
     
         15 . A liquid crystal display comprising a direct backlight unit comprising the multi-layered light diffusion plate according to  claim 1 .