Planar lighting device
AssigneeFUJIFILM Corporation
InventorOsamu IWASAKI
Life of this patent
Estimating the term…
Abstract
The absolute value of the light amount is increased by providing main light sources and auxiliary light sources on four sides of a light guide plate having a flat and rectangular light exit plane whereas the amounts of light emitted by LED chips of the main light sources and the auxiliary light sources are adjusted such that illuminance is highest near the central area of the light guide plate to obtain a high-in-the-middle, bell-curve illuminance distribution for light emitted by the light guide plate. A planar lighting device achieving a reduced thickness and weight and capable of emitting an increased amount of illumination light is provided.
Claims8
A planar lighting device comprising:
- a light guide plate including:
- a light exit plane being flat and rectangular, for emitting planar light;
- four light entrance planes, each for admitting light traveling parallel to said light exit plane, and each being formed along each of four sides of said light exit plane;
- and
- a pair of rear planes being formed on a side opposite from said light exit plane and inclined such that a thickness of said light guide plate in a direction perpendicular to said light exit plane grows thicker with an increasing distance from each of a pair of opposite light entrance planes in said four light entrance planes and joining each other in a middle between said pair of opposite light entrance planes;
- and
- four light sources, each for emitting each of said four light entrance planes and for admitting the emitted light through said four light entrance planes, and each being disposed opposite each of said four light entrance planes of said light guide plate,
- wherein each of said four light sources has LED chips and a support for supporting said LED chips, and
- wherein said LED chips of each of said four light sources are arrayed on a plane of said support facing each of said four light entrance planes in a longitudinal direction of each of said four light entrance planes.
Dependencies are inferred from the claim text.