Optical disc and apparatus for reading this disc

摘要

In the optical disc according to the present invention, servocontrol areas arranged periodically on each of the tracks of the disc are offset sequentially by a predetermined distance with respect to that of the adjacent tracks viewed in the radial direction of the disc. The apparatus used to read signals from the optical disc comprises a circuit (8, 9) for detecting in a detection signal provided by a photodetector a servocontrol signal originating inside the micropits of the servocontrol areas, a circuit (11) for generating a clock signal synchronised with the servocontrol signal, a counter (10) for providing a count value representing the number of pulses counted in tempo with the servocontrol signal and a circuit (12) for generating a light spot speed signal from the count value obtained. <IMAGE>