BACKLIGHT FOR DISPLAY DEVICE

PROBLEM TO BE SOLVED: To provide a backlight for a display device capable of uniformly dispersing light from a backlight using an LED as a light source. SOLUTION: Part of a side surface light of a light-emitting diode 344 goes to a reflection plate reflected at a light guide plate by Fresnel reflection, and one part, after it goes to a light guide plate 342 by refraction, contributes to a uniformity through a series of processes emitting outside. Also, a light going between 0 degree to 20 degrees directly above the light-emitting diode 344 is totally reflected R at a light reflection groove G of the light guide plate 342 and made to return inside the light guide plate 342, and either totally reflected on a bottom surface of the light guide plate 342 on the way of going inside of the light guide plate 342 again, or made to return, then reflected and going to an upper surface of the light guide plate 342. Like this, the light emitted directly on the light-emitting diode 344 is recycled by the total reflection, so that a reflection efficiency of the total reflection is extremely high, and there is little optical loss. Also, the light guide plate 342 having the light reflection groove G can be manufactured by an injection molding method using a framework. COPYRIGHT: (C)2006,JPO&NCIPI