| 摘要 |
PROBLEM TO BE SOLVED: To obtain a side light surface light source device capable of easily and surely preventing the luminance unevenness by the shape of a frame by forming a lightproof layer containing particulates of high light reflectivity over the entire surface in a section superposed on the rear surface of a light guide plate. SOLUTION: The lightproof layer 4B is formed by ink containing the particulates of titanium oxide which are the particulates B of the high light reflectivity. As a result, the leak light LA transmitted through a sheet material 4A is irregularly reflected by the particulates B at this lightproof layer 4B and the light quantity of the leak light LA transmitted through a reflection sheet 4 is decreased stepwise as compared with the case the reflection sheet 4 is composed of the sheet material 4A alone. Further, even the leak light LA arriving at a rail 11B by transmitting the lightproof layer 4B is irregularly reflected by this rail 11B and is then irregularly reflected by the particulates B of the lightfproof layer 4B and the sheet material 4A. This light is diminished to an extremely small light quantity when arriving at the light guide plate 2 in the end. As a result, the luminance unevenness may be prevented by the simple treatment of applying a coating on the sheet material 4A. |
