Patent ID: 8322869

Claim:
An optical film comprising, in the following order: a support; an antiglare layer having an uneven surface; a high refractive index layer; and a low refractive index layer, wherein an arithmetic average roughness (Ra) of the optical film is: 0.03 μm<Ra<0.4 μm, an average distance of unevenness (Sm) of the optical film is: 80 μm<Sm<700 μm, a region of 0°<θ<0.5° of the optical film, where θ is a tilting angle of the unevenness, accounts for 40% or more, and wherein the region is determined as follows: (i) a distribution of the tilting angle θ is determined using Model SXM520-AS150 manufactured by Micromap Corporation having an objective lens with a magnification of 10 times, a measurement unit of the tilting angle is 0.8 square micrometer, and a measurement range is 500,000 square micrometers (0.5 square millimeters) and using a method wherein (a) apexes of a triangle having an area of 0.8 square micrometers are assumed to be on a transparent film base material, three perpendicular lines are extended vertically and upwardly from the apexes of the triangle, a second triangle is formed by three points at which the three perpendicular lines intersect with the film surface, an angle formed between a normal to a plane of the second triangle and a perpendicular line vertically and upwardly extended from the support is the tilting angle θ of the film surface; (b) a part with an area of 500,000 square micrometers (0.5 square millimeters) or more of the top of the transparent film base material is divided into triangles to create measurement points for each triangle, and the tilting angle distribution of all measurement points is examined; (ii) a frequency at a tilting angle of 0 to 0.5° is calculated from the obtained tilting angle distribution; and (iii) a measurement is carried out at five different sites, and an average value is calculated; the antiglare layer contains at least one kind of light transmissive particles having an average particle diameter larger than an average film thickness of the antiglare layer by 0.01 to 4.0 μm, an amount of the light transmissive particles to be added is 0.01 to 1 mass % based on a total solid content of the antiglare layer, and an integral reflectance of the optical film is 1.5% or less.