To provide a surface light source device, which includes a light diffusion plate, a luminance adjusting sheet, and a prism sheet arranged sequentially on a light emission side of a plurality of linear light sources to balance luminance distribution in the entire surface light source device.
A light diffusion plate having total light transmissivity of not lower than 65% defined by JIS K 7361 is used as the light diffusion plate. The luminance adjusting sheet is used wherein an adjusted value Cm defined by an expression (3) below is Cm0%, and an average adjusted value C obtained by averaging the adjusted values Cm is 0C35% (m is an integer, and 2mn-1, the following are same). The expression (3) is Cm=Tm/Sm100(%). Sm is amplitude before adjustment, and Tm is amplitude after adjustment.
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ISHII ETSUKO
TAKADA TOMOYUKI
MUTO KUNIAKI
MAEDA SHUICHI
Tadashi Takahashi
Suzuki Mitsuyoshi
Noriko Yanai