Patent ID: 9606270
Date: 2017-03-28
CPC Classifications: G02B

Claim:
1. A method for manufacturing an optical sheet comprising a base material layer, and an optical functional layer which has light-transmissive portions capable of transmitting light and formed in a row along a surface of the base material layer, and which has grooves arranged between the light-transmissive portions, wherein the method comprises the steps of forming the light-transmissive portions on one surface side of the base material layer and of rolling up a belt like optical sheet comprising the base material layer and the optical functional layer; forming the light-transmissive portions by filling a spiral-shaped groove(s) with a resin, the spiral-shaped groove(s) formed on the outer circumferential surface of a cylinder mold roll and having a longitudinal direction inclined at an angle with respect to the circumferential direction; and removing the resin from the cylinder mold roll after the resin is cured, so that a longitudinal direction of the grooves arranged between the light-transmissive portions is oblique at an angle of 0.5° or more and 10° or less with respect to the longitudinal direction of the belt-like optical sheet; the method comprises the step of forming light-absorbing portions by providing a black resin ink containing light-absorbing particles whose average particle diameter is 1 μm or more and a binder made of a resin in which the light-absorbing particles are dispersed, filling the grooves with the black resin ink while scraping off an excess of the black resin ink with a doctor blade, and curing the binder; and the method comprises the steps of manufacturing an optical sheet roll formed by rolling up the belt-like optical sheet, and cutting out from the belt-like optical sheet provided to the optical sheet roll, an optical sheet in a square shape having a side parallel to the longitudinal direction of the belt-like optical sheet.