Patent ID: 7275853

Claim:
An illuminating device comprising: a light source; and a light guide plate for introducing light of the light source from a side end face to an interior and emitting said light propagated in the interior from an emitting face opposing an illuminated body to illuminate said illuminated body, wherein a prism shape for reflecting the propagating light within the light guide plate and emitting the propagating light to said emitting face side is formed on the emitting face of said light guide plate, said prism shape is constructed by plural projecting stripes formed on said emitting face, and a slanting face portion is formed on an advancing direction side of said propagating light of said projecting stripe, and an inclination angle of said slanting face portion is set to 40° or more and 60° or less, wherein an angle formed between an advancing direction of the propagating light incident to said slanting face portion and an advancing direction of reflected light of the propagating light is an obtuse angle.