| 摘要 |
PURPOSE:To perform stable recording, reproducing, or erasing even in case of slight deviation of tracking at the time of initialization by initializing an address information area more widely than a data information area. CONSTITUTION:The laser light emitted from a light source 14 forms an approximately circular beam on an optical disc 8, and the reflected light is led to photodetectors 19 and 18 which read out a servo signal for tracking control. On the other hand, the laser light emitted from a light source 1 forms an elliptic beam on the optical disc 8, and the reflected light is received by a photodetector 23, and a reflection signal 23-a is supplied to an address reading circuit 24 to obtain an address reference signal 24-a, and this signal is allowed to pass an address gate generating circuit 25 to obtain an address gate signal 25-a. A switch 26 is turned on by the address gate signal 25-a in case of negative logic, and a reference voltage in the output of a subtractor 20 is added by an adder 21, and the output is supplied to a driving circuit 22. Thus, the address information area is initialized widely.
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