| 摘要 |
<P>PROBLEM TO BE SOLVED: To allow unevenness in colors of light emitted from each LED to be less noticeable and enable uniform lighting without variations in brightness, in a surface light source device using a plurality of LEDs and a lighting unit using the same. <P>SOLUTION: Recesses 7 are formed on the side of the backside 4a of a light flux control member 4 at positions corresponding to LEDs 5. Each of the recesses 7 is formed into such a shape that, with regard to light emitted from the LEDs 5 within an angle range at least from a direction in which light of maximum intensity is emitted to a direction in which light with a half value of the maximum intensity is emitted, among the lights emitted from the LEDs 5, an emission angle θ1 of light emitted from the LEDs 5 with respect to the normal line direction of an emission surface 4b of the light flux control member 4 and an emission angle θ5 of light emitted from the light flux control member 4 satisfy the relationship of θ5/θ1>1 excluding light in the vicinity of the normal line among the lights emitted from the LEDs 5, and that the value of θ5/θ1 changes to gradually decrease as θ1 increases. <P>COPYRIGHT: (C)2007,JPO&INPIT |
