| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical sheet for a liquid crystal display device having optical functions, especially a markedly high optical diffusion function, and to provide a backlight unit, wherein improvement in quality including optimized angle of view, erasure of lump images, thin profile, and the like, is promoted by using the optical sheet. <P>SOLUTION: Disclosed is the optical sheet for the liquid crystal display device having a microlens array on the surface thereof, wherein the rear surface has a fine ruggedness shape, and the surface roughness Ra (arithmetic average roughness) of the rear surface is 1.5 to 4.0 μm. It is preferable that microlenses which constitute the microlens array of the surface have average a radius of 3 to 90 μm and that the surface roughness Ra of the rear surface be 1/50 to 1/2 times the average radius of the microlens. For the surface roughness Ra of the rear surface, a ratio (Rz/Ra) of Rz (ten-point average roughness) to Ra lies, preferably, in a range of 1 to 40. <P>COPYRIGHT: (C)2010,JPO&INPIT |
