| 摘要 |
PURPOSE:To prevent recording by mistake in waiting state of operation and prevent malfunction at the time of track retrieving etc. by stopping irradiation of a light beam when a specified time lapsed after the light beam stopped on a light card. CONSTITUTION:When operation is completed, a motor 21 stops, and a light beam stands by in the state of standstill possessing power PWL or PR. When the motor 21 stops, a speed detecting circuit 29 detects that relative speed V of the light card and light beam became zero, and operates a time measuring circuit 30. Here, a specified time TOFF is set to the time measuring circuit 30, and when time (t) after becoming V=0 became equal to TOFF, an irradiation stop signal is sent to a laser driving circuit 31, and light emission of a semiconductor laser 11 is stopped. |
