To provide a prism sheet, when being used as a prism sheet for a backlight unit used for a liquid crystal display, in such a manner that the side of a prism line is arranged directed toward the light-emitting face of a light guide plate, which effectively suppresses unevenness of luminance without remarkably reducing the front luminance, also more reduces the number of parts than the conventional backlight unit, and can make the liquid display small in thickness.
A light-shielding layer is provided at the face on the opposite side to a prism line in a prism sheet and also at the part along at least one side of the edge part of the sheet. The light-shielding layer comprises a diffusion reflective layer, in which the minimum value of the diffusion reflectance in the wavelength of 400 to 760 nm is 30%, and also, the maximum value of the regular reflectance is 15% as the layer facing the prism line.
MIYAMOTO MASAFUMI
SAGA RYUICHI
