| 摘要 |
PURPOSE:To compensate a secular change in the light transmittivity of optical parts and a decrease in light output due to the accumulation of dust on a focusing lens by placing a photodetector for monitoring a laser output opposite to the focusing lens, and moving it away from the position during recording and reproduction. CONSTITUTION:A holder 35 for holding the photodetector 23 for monitoring is so constituted that the photodetector 34 is movable from right above an optical head 31 to where an optical disk 44 is loaded, and energized toward a pin 38 by a spring which is not shown in a figure. The photodetector 34 moves from over the focusing lens 25 to behind an optical head 31 (to left in the figure) by a cartridge 43 together with the holder 35. The disk 44 is attached to a spindle motor 41 after the loading operation to set the disk 44 over the focusing lens 25. |
