| 摘要 |
PURPOSE:To prevent the generation of ghosts by defining a face opposite to the face turned to a photodetecting means as a face which does not reflect the light beam given from a light source toward the photodetecting means among six faces of a beam splitter. CONSTITUTION:A polarized beam splitter 4 has six faces, and the face (a) opposite to the face (c) which is turned to a photodetecting element 13 is set vertical or slant to the optical path (g) of a light beam. As a result, the light beams (b) and (d) reflected from the face (a) are led to the outside of optical paths (f) and (g) and never reach the element 13 and a light source 1. This pickup prevents the generation of error signals and the deterioration of the S/N. |
