| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface light source device and liquid crystal display device using a light guide plate with which controlled diagonal emission is possible and fine luminance unevenness is prevented. SOLUTION: Many microreflectors 90 formed at the back 34 of the light guide plate 30 have guide sections and conversion output sections having valleys. The conversion output sections reflect input light P twice on an internal slope and form internal output light Q inclined in a direction parting from an incident surface 32. The internal output light Q is made incident on the inside of the slopes of projecting arrays PR of an exit surface 33 and part thereof turns to direct escape light. Much of the remaining light arrives again at the exit surface 33 through diversified optical paths. The light escaping at second and subsequent chances turns to the indirect escape light. The direction of the exit light adequately mixed with both is corrected nearly to a front direction by a prism sheet PS and the liquid crystal display panel, etc., are illuminated with this light. The fine luminance unevenness is prevented by mixing of the direct/indirect escape light. The indirect escape light is increased if a reflector FF is arranged. |
