Edge light-type backlight device and light diffusion member

摘要

This edge light-type backlight device comprises a light guide plate, a light source disposed at one end part of the light guide plate, a light diffusion sheet and a prism sheet on a light emission face of the light guide plate. The refractive index of the prism sheet exceeds 1.60, a peak of emitted light distribution of the light emission face in a plane parallel to the one end part of the light guide plate and orthogonal to the light emission face is within an angle ranges of 30°˜45° and −30°˜−45° with respect to a normal direction of the light emission face. The emitted light of the light emission face diminishes toward an emission angle −90° or 90° with respect to the normal line from the angle ranges of the peak of the emitted light distribution. High frontal brightness and diffusion are realized.

主权项

1. An edge light-type backlight device comprising:
a light guide plate; a light source disposed at one end portion of the light guide plate; and a light diffusion sheet and a prism sheet successively disposed on a light-emitting surface of the light guide plate, wherein: the prism sheet has a refractive index of more than 1.60; a peak of an emitted light distribution on the light-emitting surface of the light diffusion sheet in a plane parallel to the one end portion of the light guide plate and orthogonal to the light-emitting surface is in angular ranges of 30 to 45° and −30 to −45° with respect to a normal direction of the light-emitting surface; and emitted light from the light-emitting surface of the light diffusion sheet is gradually decreased from the angular ranges of the peak of the emitted light distribution toward an emitting angle of −90° or 90° with respect to the normal direction.