METHOD FOR MANUFACTURING OPTICAL SHEET, OPTICAL SHEET, EL ELEMENT USING OPTICAL SHEET, AND LIGHTING DEVICE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide an optical sheet which allows acquisition of a desired lens shape and high diffusion performance and can provide high surface scratch-resistant performance, by using a cylinder-like mold as a pattern master and using an active energy ray-curable resin on a light-transmissive substrate to form the optical sheet.

SOLUTION: In the method for manufacturing an optical sheet, a rugged part is formed by crimping a mold 40 having a rugged structure to a surface of a light-transmissive substrate via an active energy ray-curable resin, and the optical sheet is manufactured so that: a contact length ratio A of a breadthwise-direction tangent length L2 of the light-transmissive substrate to a breadthwise-direction tangent length L0 of the mold 40 in a crimping part between the mold 40 and the light-transmissive substrate without the curable resin therebetween is equal to or higher than 0.1 and equal to or lower than 0.7; there are no contact points between a mold release auxiliary part 42 given to the surface of the mold 40 and the light-transmissive substrate; there are at least one or more contact parts and non-contact parts between the mold and the light-transmissive substrate; and a distance h1from the light-transmissive substrate to a concave portion 42a of the mold release auxiliary part 42 in a normal direction of the light-transmissive substrate is longer than 20 μm and shorter than 200 μm.

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