| 摘要 |
A light diffusion element having a passage section that allows light advancing substantially parallel to the optical axis to pass as a first light without diffusion and having a diffusion section that causes light spreading into the region outside a predetermined angle from the optical axis to scatter and emits the light as a second light. In a light irradiation area defined in a region to which the first light is irradiated, the second light controls illumination distribution in the light irradiation area. The light diffusion element can minimize optical loss, and in addition, the element can excellently control a diffusion angle and a light irradiation area, and enables a cost reduction. |
