Patent attributes
A planar lighting device is capable of keeping the light entrance plane of the light guide plate spaced a constant distance from the light source and the light guide plate spaced a constant distance from the liquid crystal display panel even when the light guide plate expands, contracts or warps. This prevents break of the light source, decrease of light admission efficiency, occurrence of uneven brightness, and break of the liquid crystal display panel and permits a thin, larger, and lightweight design. The planar lighting device includes a fixing member for keeping them spaced from each other, a housing for accommodating the light source and the light guide plate, a sliding mechanism to elastically hold the fixing means against the housing while keeping the light source spaced a constant distance from the light guide plate, and a reinforcing member for reinforcing the housing.