| 摘要 |
PROBLEM TO BE SOLVED: To improve quality of illumination light in a surface lighting device having a light guide plate manufactured by injection molding.SOLUTION: A surface lighting device 10 is provided with a light source 52, a light guide plate 12 which is constructed so as to emit light emitted from a light source 52 as surface light, and a housing frame 32 having side walls 36-39 for surrounding outer periphery side faces 16-19 of the light guide plate 12. Projections 22, 24 for positioning the light guide plate 12 to the housing frame 32 are formed in the outer peripheral side faces 17, 19 of the light guide plate 12, and the light guide plate 12 is injection molded with an inlet port provided at the side end part of the projection 22. Thereby, by separating away the cross-section of a cutting impress 23 of the inlet port from the outer peripheral side face 17, an effect of abnormal emission of this cross-section on the illumination light can be reduced. |
