| 摘要 |
PURPOSE:To facilitate setting relative positional dimensions of a spindle motor, a half mirror, and a photodetector by arranging them so that the line connecting respective centers of the spindle motor and the mirror and the optical axis of the light, which is transmitted through the half mirror and reaches the photodetector, cross each other at an acute angle >=45 deg.. CONSTITUTION:A turntable bearing spindle motor 59, a half mirror 39 which is inclined to the optical axis of the converged light passing the recording face of a recording medium disk 44 and gives astigmatism to the light, a mirror 40 which is provided between the recording face and the half mirror, and a photodetector 46 which receives the light transmitted through the half mirror are provided. They are so arranged that the line connecting respective centers of the spindle motor 59 and the mirror and the optical axis of the light, which is transmitted through the half mirror 39 and reaches the photodetector, cross each other at an acute angle >=45 deg.. Through dimensions of the outside diameter of an optical information recording and reproducing device are limited for the purpose of making the device small-sized, the half mirror and the photodetector are considerably separated from the spindle motor, and setting of relative positional dimensions of these parts is made easy. |
