| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical diffusion sheet having a satisfactory directive optical diffusion function, light beam transmissivity, economic efficiency and thin film property and a back light unit which has improved performance such as luminance and is made thin. SOLUTION: The optical diffusion sheet is equipped with a transparent base material layer and an optical diffusion layer to be layered on the front side of the base material layer and the optical diffusion layer has beads made of resin and a binder made of resin. The optical diffusion sheet is characterized in that monodisperse beads with average particle diameter of≥1.5μm and≤5μm are used as the beads, mass ratio of the beads to the binder is≥2.5 and≤3 and layered quantity of the optical diffusion layer is≥3g/m<SP>2</SP>and≤10g/m<SP>2</SP>. It is good to use acrylic resin as base polymer of the beads and the binder. As a variation coefficient of particle diameter distribution of the monodisperse beads, 0.2 or less is desirable. As a forming method of the optical diffusion layer, a gravure coat method is desirable. COPYRIGHT: (C)2005,JPO&NCIPI
|
