| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical element attachable to the existing optical system, and forming two optical paths of the direct viewing and the lateral viewing and capable of simultaneously imaging the front and all surrounding directions.SOLUTION: An optical element is formed of a rotation symmetrical transparent medium La around the central axis 2. The transparent medium La includes: a first transmission surface 11, a first reflection surface 12 arranged on a center axis 2 of the first transmission surface 11; a second reflection surface 13 arranged opposite to the image surface 5 of the first reflection surface 12; and a second transmission surface 14 arranged at the image surface 5 of the second reflection surface 13. A through-hole Lb is formed at a position including the central axis 2 of the transparent medium La. Light incident on the transparent medium La passes through a side viewing optical path A and a direct-viewing optical path B. The side viewing optical path A, in the order of forward ray tracing, enters the transparent medium La through the first transmission surface 11, and is reflected by the first reflection surface 12 disposed opposite to the image surface 5 and reflected by the second reflection surface 13 to the image surface 5, and constitutes a substantially Z-shaped optical path going to the outside from the transparent medium La to the image surface 5 through a second transmission surface 14. The direct-viewing optical path B constitutes an optical path penetrating a through-hole Lb.SELECTED DRAWING: Figure 1 |
