| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a surface light source for obtaining more uniform brightness by further suppressing brightness irregularity. <P>SOLUTION: One end face of a light guide plate 3 is made an incident end face 3a, a light source chip 2 is arranged on the center part and light is made incident on the inside of the light guide plate 3 from its position. A plurality of circular-arc prisms 4 are concentrically provided on the reverse side face to an emission face 2a of the light source chip 2 by centering a center point So of the emission face 2a of the light source chip 2. The prisms 4 are continuously provided from the end face to the end face of the light guide plate 3. In addition, pitches of the prisms 4 are constant in the depth direction (namely, the direction of distance L from the center point So) of the light guide plate 3, and its depth D from a virtual plane 3c in parallel to the emission face 3b increases with the increase in the distance L. <P>COPYRIGHT: (C)2004,JPO |
