| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical sheet which has remarkably high optical functions such as a light diffusing function, a function of refraction to a normal direction side, and a light converging function, and to provide a back light unit which can be improved more in quality such as, high luminance to its front direction and leveling of luminance and made thinner by using the optical sheet. <P>SOLUTION: The optical sheet 1 is equipped with a transparent base material layer 2 and an optical layer 3 laminated on the surface side of the base material layer 2 and the optical layer 3 has spherical resin beads 5 in a binder 4. The optical sheet is characterized in that (a) the mathematical mean roughness of three-dimensional surface roughness of the optical layer 3 is 5 to 14 μm and (b) 10-point mean roughness of three-dimensional surface roughness of the optical layer 3 is 50 to 80 μm. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
