| 摘要 |
PROBLEM TO BE SOLVED: To provide a flat light source, especially a backlight for a liquid crystal display device, with a simple structure, minimizing the light loss in a liquid crystal panel. SOLUTION: This flat light source illuminating an object has a light source; a light guide plate leading the thereinto from the end face opposite to the light source and diffusing the light, and reflecting the light on a reflection face to project the reflected light to the outside; and a prism sheet transmitting the reflected light and projecting the transmitted light as projection light in the normal direction to the object. A vertical angle of each microprism of the prism sheet is <=40 deg., and the microprisms are disposed face up. |
