Disc accessing using coarse and fine actuators with the fine actuator locked during coarse actuator movement

An information memory accessing apparatus comprising:

• a rotary recording medium;
• a coarse actuator;
• a fine actuator;
• a head which is positioned at a desired track of said rotary recording medium by means of said coarse actuator and said fine actuator;
• a detector for detecting movements of said fine actuator;
• a lock signal generator for comparing a first output signal produced from said detector immediately prior to initiation of an access operation of said coarse actuator with a second output signal subsequently produced from said detector during the access operation of said coarse actuator to produce a comparison output signal;
• and
• means, responsive to said comparison output signal from said lock signal generator, for locking said fine actuator during the access operatin of said coarse actuator.

An optical information memory accessing apparatus comprising:

• a rotary recording medium capable of at least one of recording or reproducing information by using a light beam;
• an optical head for irradiation of said light beam onto said rotary recording medium;
• a first actuator for moving said optical head in a radial direction of said recording medium;
• a second actuator, carried on said optical head, for controlling a radial irradiation position of said light beam on said rotary recording medium;
• detector means for detecting movements of said second actuator;
• lock signal generator means for comparing a first output signal produced from said detector means immediately prior to initiation of an access operation of said first actuator with a second output signal subsequently produced from said detector during the access operation of said first actuator to produce a comparison output signal and for generating on the basis of said comparison output signal a lock signal;
• and
• means, responsive to the lock signal from said lock signal generating means, for locking said second actuator at a state occurring immediately prior to the initiation of said access operation during said access operation of said first actuator.