LIGHT DIFFUSING SHEET, AND BACKLIGHT UNIT USING THIS LIGHT DIFFUSING SHEET

摘要

[PROBLEMS] A light diffusing sheet which can guide a light from the light guide sheet or the light source of a backlight unit to a lens film in the form of a diffusion light having a small luminance peak angle, is not likely to produce a moiré, an interference fringe and an uneven luminance, and is advantageous in productivity and cost, and a backlight unit with this light diffusing sheet built in. [MEANS FOR SOLVING PROBLEMS] The light diffusing sheet (10) consisting of translucent resin comprises, formed on at least one surface (2) thereof, fine recesses (3) having any one of the shapes of an inverted pyramid, an inverted truncated pyramid, an inverted circular cone, and an inverted truncated circular cone. A light refracting action by the inclined surfaces or the tapered surfaces of the fine recesses (3) reduces the luminance peak angle of a diffusion light and limits a moiré and an interference fringe. The backlight unit comprises this light diffusing sheet located on a light guide sheet (20) or in front of a light source so that fine-recesses-formed surface thereof acts as a light outputting surface.