SURFACE LIGHT SOURCE DEVICE

摘要

A surface light source device is used as a back light for a liquid crystal display device and the like, and does not cause any slackness of a light diffusion sheet (2) and a reflective sheet (4) in spite of changes in temperature and humidity. Flanges (6a, 6b) of a holder (6) are mounted to both facing surfaces of a light conductive body (1) such that gaps slightly greater than the thicknesses of the light diffusion sheet (2) and reflective sheet (4) are formed between the flange (6a) of the holder (6) and an outgoing surface (1a) of the light conductive body (1) and between a surface (1b) opposite to the outgoing surface of the light conductive body and the flange (6b) of the holder (6). One end of the light diffusion sheet (2) and reflective sheet (4) is disposed in the gaps so as to enable freely moving in a predetermined range, and the other end of the light diffusion sheet (2) and reflective sheet (4) is secured to the light conductive body (1) by fixing means (3, 5; 10; 14).