| 摘要 |
PROBLEM TO BE SOLVED: To provide a lighting device having a light guide plate which can reduce the used number of optical sheets and can irradiate light effectively to a display.SOLUTION: The lighting device has the light guide plate 1, a light source 2 arranged on a side face of the light guide plate 1, and a reflecting prism train 11 as a plurality of prism trains intermittently formed in a first direction which specifies a distance from the light source 2 at a back surface of the light guide plate 1. Each of the plurality of reflecting prism trains 11 has a cross section in the first direction of the light guide plate 1, the cross section having a sawtooth shape of a repetitive valley-mountain shape the section nearest to the light source 2 of which is a valley, each valley of the sawtooth shapes is retreated from a flat face at the back surface of the light guide plate 1, and inclined surfaces 11a, 11b, 11c forming each valley at the side nearer to the light source 2 than facing inclined surfaces, as respective light source side inclined surfaces, mixedly have inclined angels of two kinds or more with respect to the flat face at the back surface of the light guide plate 1. |
