To provide a planar light source without fear of light leak or a local bright spot, and free from unevenness of brightness of a screen even if a device is downsized, in one used for a liquid crystal display or the like.
The planar light source 1 comprising point light sources 2 consisting of LEDs, and a light guide plate 3 of nearly a flat shape seen as a whole for reflecting light incident from a base end face 3a side at a rear face 3d as well as a far end face 3b and emitting it from a light-emitting face 3c has a condensing structure 4 having a condensing function consisting of two prism sheets crossing each other in the vicinity of the base end face 3a, or a mirror finish structure 5 in the vicinity of the base end face 3a as well as a condensing structure 4 at a light-emitting face 3c or in the vicinity of a base-end face side. An angle made by the light-emitting face 3c and the base end face 3a of the light guide plate 3 is within a constant range, the point light sources 2 made of LEDs are arranged either above or under the base end face 3a, and the LEDs are structured to be at a given angle with each other.
YASUMOTO TAIZO
MORITA YOSHIKUNI
| JPH11144515A | 1999-05-28 | |||
| JPH11265610A | 1999-09-28 | |||
| JP2000299011A | 2000-10-24 | |||
| JPH11305225A | 1999-11-05 | |||
| JP2001160312A | 2001-06-12 | |||
| JPH10268307A | 1998-10-09 |
| WO2004055429A1 | 2004-07-01 |
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