| 摘要 |
PURPOSE:To increase the illuminance and make it uniform by forming a plurality of grooves consisting of two inclined planes at one surface of a clear plate, forming the inclined planes with a certain angle which meets specific conditions, and arranging there a reflex plate. CONSTITUTION:A light source 2 is installed near each end of a clear plate 1. A plurality of grooves 1b are formed at one surface 1a of this clear plate 1. Each groove 1b is formed from two inclined planes 1c, 1d. The inclination angles thetaa, thetab of these inclined planes 1c, 1d, which are facing the light source 2, to the surface 1a are set in such a range that the beams of light a, b from the light source 2 incident to the clear plate 1 in parallel with the surface 1a are all-reflected by the planes 1c, 1d and that the all-reflected beams of light will not ne all-reflected by the other surface 1e of the same clear plate 1. Also a reflex plate 4 is arranged on the surface 1a side. The chromatic temp. of the beams of light reflected thereby can be adjusted by changing the color of this reflex plate 4. |
