| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a surface light source device capable of suppressing luminance unevenness without applying a special processing on a light diffusion plate. <P>SOLUTION: The surface light source device 20 is provided with: a plurality of light sources 31 which are point light sources and are arranged two dimensionally; and a light diffusion plate 40 which diffuses light from the plurality of light sources 31. Each of light-distributions I(θ) of the respective plurality of light sources 31 is set so as to satisfy following formula (1) based on: an emitting angle θ of light from each light sources 31; a forward-direction radiation-intensity function f (θ, 0) of the BTDF (Bidirectional Transmission Distribution Function) of the light diffusion plate 40; and a forward-direction luminance profile p(θ) by each of the plurality of light sources 31 of the surface light source device 20 which is of a triangle shape, a trapezoid shape or a rectangle shape taking into account overlap in order to make the forward-direction luminance of the surface light source device 20 constant. Formula (1): I(θ)=(cosθ)<SP>-2</SP>äf(θ, 0)}<SP>-1</SP>p(θ). <P>COPYRIGHT: (C)2011,JPO&INPIT |
