| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical disk player stably reproducing a recording data signal on a optical disk without being affected by dispersion in light quantity, output fluctuation and noises in a high frequency band when a light source emits a high harmonic laser beam. SOLUTION: When the light source 1 becomes a certain level or below, for preventing the pull-in of a servo signal, and for preventing the lead-out of its data signal and the servo signal, etc., for example, a voltage from a reference voltage source 31 of servo on/off is compared with a signal from an amplifier 30 by a comparator 32, and only when the result becomes a prescribed value or above, respective switching elements 28A-28D are closed, and the output signal of respective target AGC controlled data signal, pull-in signal, tracking servo signal, focus servo signal, etc., are take out, and when the light source 1 is the certain level or below, respective switches 28A-28D are opened, and the lead-out of respective signal are avoided. |
