PROBLEM TO BE SOLVED: To sufficiently suppress the occurrence of luminance unevenness between each light source and a region between light sources even when the direct type backlight is further thinned. An optical sheet (43) is incorporated between a plurality of small light sources (42) and prism sheets (44, 45) in a liquid crystal display device in which a plurality of small light sources (42) are dispersedly provided on the back side of a display screen. At least one surface of the optical sheet 43 has an uneven shape. A flat surface that appears when the uneven shape is virtually removed is defined as a virtual plane, and a minute region having a predetermined projected area with respect to the virtual plane is two-dimensionally displaced along the virtual plane at equal intervals. When the surface with unevenness included in the micro area at each position is approximated to a plane and the inclination angle formed by the plane approximated to the plane and the virtual plane is obtained, the inclination angle with respect to the total area of the micro area at each position The ratio of the total area of the minute regions having an angle of 30° or more is 30% or more. [Selection diagram] Figure 2
展开▼
