Patent attributes
The planar lighting device includes a light guide plate including two symmetrical, inclined planes increasingly distanced from the light exit plane with the increasing distance from the light entrance planes toward the center, a curved portion joining the inclined planes, and scattering particles dispersed therein; light sources; a housing; a securing unit securing the light sources and light guide plate to keep their distance constant, and a sliding mechanism allowing the securing unit to slide. Distance between the light entrance planes, thicknesses at the light entrance planes and at the central curved portion, its radius of curvature and taper of the inclined planes are all held within respective given ranges as well as scattering particle diameter and density, light use efficiency and middle-high ratio of the brightness distribution.
