| 摘要 |
PURPOSE:To enable to obtain accurate reproduction signals by installing a quarter wave length plate slanting it to the optical axis of a light beam. CONSTITUTION:The quarter wave length plate 18 is installed slanting it at specified angle theta to a horizontal line I which is right angles to a light beam advancing in the direction shown by an arrow mark A. Consequently, out of light beams that advance in the direction of arrow mark A, light component reflected by the quarter wave length plate 18 advances in the direction of arrow mark C shown by dotted lines and does not return in the direction of arrow mark B. Accordingly, only light reflected by a disk 20 is received by a light detector 22, and accurate reproduction signals can be obtained. |
