SURFACE LIGHT SOURCE UNIT AND DEVICE USING THE UNIT

摘要

Glaring and uneven luminance on a screen is limited when used for image displaying for a liquid crystal display unit or the like. A surface light source unit comprising a light emitting unit (22) using an LED or the like, and a light guide plate (23) for guiding light emitted from the light emitting unit (22) to spread it over the entire light output surface, wherein many deflection patterns (34) are provided on the rear surface of the light guide plate (23), and the deflection patterns (34) are used for reflecting a light in the light guide plate (23) to enable the light to be outputted from the light outputting surface of the light guide plate (23). When a polar coordinate using as the origin the center point set in the vicinity of one corner of the light guide plate is assumed, a location point (Rm, thetam) of a deflection pattern (34) is expressed in the following expressions (Ro > 0). Rm= Rm-1 + (1/Rm-1) thetam= thetam-1 + 137.5°