| 摘要 |
A light collector includes a light guide having a refractive index larger than a refractive index of air and a reflecting surface configured to reflect light output from a conic surface of the light guide back to the light guide. The light guide is made of transparent material through which light passes. The light guide has an entering portion from which light enters and an exiting portion from which the light exits. The light guide has a circular cone shape and has a cross-sectional area that decreases in a direction from the entering portion to the exiting portion. |
