| 摘要 |
PURPOSE:To reflect all incident light beams by forming an optical reflecting element of a transparent material having a reflecting surface obtained by rotating a curved line having a focus around an axis and an incidence surface obtained by rotating an arc drawn around the focus as a center around an axis. CONSTITUTION:A 1st bowl-shaped reflecting full-length mirror 50 which has a light transmission hole 50a in its center inner bottom part is sectioned in a parabolic surface shape and a concave mirror whose internal surface is a mirror surface. When an optical transmitter is placed at a distance, this concave mirror 50 reflects and converges incident lights L1, L2... which are nearly parallel to the axis Z on the focus P1. An optical reflecting element 51 formed of transparent glass or synthetic resin as a 2nd reflecting mirror consists of a circular external surface part 52, a curved surface part 53, and a body part 54. Then the circular external surface part 52 is in the shape obtained by rotating the arc which contains the focus P1 of the concave mirror 50 in its center around the axis Z. Light beams traveling to the focus P1 from the outside of the circular external surface part 52 are made to travel straight at the incidence point on the circular external surface part 52. |
