OPTICAL SHEET AND BACK LIGHT UNIT USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide an optical sheet excellent in optical performance such as diffusing and condensing light and to provide a back light unit having the optical sheet in which the luminance can be improved and irregularity in the luminance can be prevented. SOLUTION: The optical sheet has a transparent base layer and an optical functional layer having beads of the average particle size of >=16 μm and <=25 μm dispersed in a binder and having >=2.4 and <=4.5 mass ratio of the beads to the binder. The surface roughness (Ra) of the optical functional layer is >=9 μm and <=16 μm and the haze of the optical sheet is >=85% and <=90%.