OPTICAL SHEET, DISPLAY DEVICE AND PRODUCTION METHOD OF OPTICAL SHEET

PROBLEM TO BE SOLVED: To prevent degradation in picture qualities of an image when such an optical sheet is used that controls a propagation direction of light in accordance with a polarization state of the light.SOLUTION: An optical sheet 40 is used for a display device that switchably displays a two-dimensional image and a three-dimensional image visible by naked eyes. The optical sheet 40 includes an optical anisotropic first layer 51 and a second layer 52 layered on the first layer. An optical interface 55 that changes propagation directions of light having one of polarization components is formed between the first layer 51 and the second layer 52. The optical interface 55 includes a plurality of unit optical interfaces 55a arranged in one direction. Each unit optical interface 55a extends in a direction non-parallel to the one direction. A rugged pattern is formed on a surface 51a of the first layer 51 opposite to the optical interface 55. An arithmetic average roughness Rax of the rugged pattern in the one direction and an arithmetic average roughness Ray of the rugged pattern in the direction where each unit optical interface extends satisfy Rax>Ray.