| 摘要 |
PROBLEM TO BE SOLVED: To eliminate light which has directivity to an improper direction and to obtain outgoing light having wide directivity by providing a linear light source, a light guide plate, a reflecting surface which is arranged closely to one surface of the light guide plate approaching and separating a flank, and plural reflecting means and making the reflecting surface into diffused reflecting one. SOLUTION: The light of the linear light source 1 is made incident on the light guide plate 3 and a prism part 3f is formed on its reverse surface 3c. A diffused reflecting plate 4 is fitted nearby to the reverse surface 3c of the light guide plate 3. Then when a light beam is made incident on the opposite side of the prism part 3c below the critical angle, the majority of the incident light is refracted on a reflecting surface and and the refracted light is entered into the prism part 3f. The refracted light is reflected on the diffused reflecting plate 4, entered into the light guide plate 3 again through the flat part 3g of the light guide plate 3, and then emitted from the top surface part 3b of the light guide plate 3. At this time, the refracted light is reflected on the diffused reflecting plate 4, so that the light is reflected on the diffused reflecting plate 4 in various directions to eliminate polarization of the outgoing light. |
