| 摘要 |
PURPOSE:To attain very quick accessing by extracting the change in a reflected light from a disk obtained through a micro lens as the stimulated change of a semiconductor laser from a photodetector. CONSTITUTION:An output light from a semiconductor laser 7 is projected onto a disk 1 via a micro lens 20 and its reflected light is returned to the laser 7 through the lens 20 and the fiber 21 again. In increasing/decreasing the returned luminous quantity depending on the state of a disk face, the excited luminous quantity of the semiconductor laser is increased/decreased and a terminal voltage is changed and a signal is detected by the self-coupling effect. A moving part integrated in a head feeder 2 is only the micro lens 2, which offers light weight and focusing/tracking control is applied by using a signal from the servo circuit 6, and the control is applied by using the wobbling method that minute vibration is applied to the projected beam to the optical disk 1 and the relation of phase between the reflected light intensity of spot and the vibration in this case is detected.
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