Mirror control circuit for optical information recording or reproducing unit

Abstract

Abstract PURPOSE: To assure the light axis of optical beam, by preventing the end-off of mirror against various noises, by eliminating the frequencies near the fundamental frequency of error signal due to eccentricity of disc and performing gain control with the error signal of other components. CONSTITUTION: The error signal I is fed to the drive coil 3 of mirror via the gain control circuit 1 and amplifier 2. Further, since the waveform due to eccentricity of disc is superimposed on the voltage at the junction a of the resistor 4 and coil 3, the fundamental frequency component due to eccentricity is eliminated via the band rejection filter 7 to obtain the output by other frequency components, and it is compared with the mirror stopper voltage E at the comparator 6 and the gain of the circuit 1 is controlled with the output of comparison. As a result, the deflection of mirror can be controlled with broad dynamic range and the end-off of mirror due to noise can be avoided. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Koichi Suzuki

Bibliographic Details