The objective of the invention is to provide an optical sheet for
liquid crystal display apparatus and a backlight unit suing the same. The optical sheet for
liquid crystal display apparatus has excellent optical functions, specifically optical
diffusion function; the backlight unit optimizes visual
field angle, removes lamp source images, becomes thinner, and also hoists the like qualities. The invention is an optical sheet for
liquid crystal display apparatus, which has a transparent substrate layer and a
microlens array, wherein the
microlens array is composed of a plurality of
microlens formed by the
substrate surface and back face, wherein the back microlens can be a concave lens, the back microlens array is preferably composed of a plurality of microlens with random
diameter, the average
radius of the surface microlens can be from 3[mu]m to 90[mu]m. In addition, the average
radius of the back microlens is from 2[mu]m to 10[mu], and is about 1 / 12 to 1 of the average
radius of thesurface microlens.