| 摘要 |
PURPOSE:To prevent a tracking error by displacing a cartridge provided at one one end of a pickup a pickup arm through a displacing member. CONSTITUTION:According to the turning of the pickup arm, a turning disk 9 turns and when a slit 10 faces a photocoupler 11, a photodetecting element (CdS) 13 is irradiated with light from a light emitting element (LED) 12. Once the CdS detects the light, its resistance value decreases, so the base potential of a transistor (TR) drops and its collector-emitter voltage rises. As the collector- emtter voltage rises, a piezoelectric element 6 is displaced and then the cartridge 4 fitted to the piezoelectric element 6 is also displaced. The extent phi of the displacement varies with the extent of turing of the pickup arm because the area of the slit 10 of the turning disk 9 is varied gradually in the turning direction. |
