To obtain desired illumination distribution characteristics without causing a problem of uneven illumination or an insufficient irradiation width in a sub-scanning direction.
In a light guide body 22 equipped with a prism forming surface 33 opposing a light-emitting surface and including a plurality of projecting prisms 41 arranged in a longitudinal direction in order to receive a light emitted from a light source at a light incidence surface on one end side in the longitudinal direction and emit the light from a light-emitting surface 32 extending in the longitudinal direction, the prisms are arranged at a constant interval, and the prism forming surface is formed so that a top part 41a of each prism is located on a first reference plane 42 consisting of a single plane and also a root portion 44 between prisms is located on a second reference plane 43 arranged so that a distance from the first reference plane changes along the longitudinal direction, thereby varying a height of the prisms depending on the required illumination distribution.
KAWANO YUZO
SANADA TAKASHI
| JP2007225788A | 2007-09-06 | |||
| JP2000310777A | 2000-11-07 | |||
| JPH11114967A | 1999-04-27 |
| WO2007099796A1 | 2007-09-07 |