| 摘要 |
PURPOSE: To provide a lighting device for a liquid crystal display plate capable of preventing leakage of light from a light transmission plate without using a bulky light shielding member, reducing the number of parts and work processes and realizing a saved space. CONSTITUTION: The light emitted from an LED 4 is made incident onto the light transmission plate 3 from a recessed part 3d. The light incident in such a manner, is multiple reflected and diffused by the surfaces 3b and 3c of the light transmission plate 3 to be diffused to the whole of the light transmission plate 3 uniformly. The angle of the side surface 3a of the light transmission plate 3 for the surface 3b is decided so that an incident angle of the light parallel to the surface 3b to the side surface 3a becomes a critical angle or above of a total reflection. Then, though the light directly hitting the side surface of the light transmission plate 3 from the LED 4 in the incident angle exists, since the light is totally reflected by the side surface 3b, no light leaks out the outside. On the other hand, the diffused light are gone out from the surface 3b uniformly to light the liquid crystal plate(LCD) 1. |
