| US 7,522,809 B2 | ||
| Planar light source and light guide for use therein | ||
| Tomoyoshi Yamashita, Kanagawa (Japan); and Masae Ono, Kanagawa (Japan) | ||
| Assigned to Mitsubishi Rayon Co., Ltd., Tokyo (Japan) | ||
| Appl. No. 10/514,787 PCT Filed May 20, 2003, PCT No. PCT/JP03/06268 § 371(c)(1), (2), (4) Date Nov. 19, 2004, PCT Pub. No. WO03/098100, PCT Pub. Date Nov. 27, 2003. |
||
| Claims priority of application No. 2002-144712 (JP), filed on May 20, 2002. | ||
| Prior Publication US 2005/0254771 A1, Nov. 17, 2005 | ||
| Int. Cl. G02B 6/32 (2006.01); G02B 6/00 (2006.01); F21V 7/04 (2006.01) | ||
| U.S. Cl. 385—146 [385/33; 362/615] | 8 Claims |
| 1. A planar light guide for a planar light source device, having a light entrance end face receiving light from a substantially
spot-like primary light source and a light exit face outputting the light which is incident on the light entrance end face,
wherein a plurality of elongated lenses are formed on the light entrance end face to extend substantially in parallel with
one another from the light exit face toward the opposite face, and include first elongated lenses and second elongated lenses,
wherein the first elongated lenses each having a symmetric cross-sectional shape are arranged in the vicinity of a middle
of the light entrance end face concerning a direction along the light exit face, and the second elongated lenses each having
an asymmetric cross-sectional shape are arranged in the vicinity of opposite ends of the entrance end face concerning a direction
along the light exit face.
|