| 摘要 |
PROBLEM TO BE SOLVED: To expand a reproducible range of data and addresses by adopting a focal position as a 1st focal position, where a data signal in a detected data area of a recording medium is in the optimal state, and adopting the focal position as a 2nd focal position, where an address signal in an address area is in the optimal state. SOLUTION: A light beam 106 is emitted onto a recording medium 110 and is also focus-controlled to reproduce a signal of a prescribed frequency pre- recorded on the recording medium 110, and a reproduced signal for adjustment is obtained by inputting an output of a split light detector 116 to a recorded signal detecting circuit 202. The reproduced signal output is inputted to a signal amplitude detecting circuit 203 and an address reading circuit 204, and both of the outputs are inputted to an arithmetic processing circuit 205 of a focal position adjusting means. The arithmetic processing circuit 205 can make the focusing state of the light beam 106 variable on the recording medium 110 by the input from the signal amplitude detecting circuit 203 or the address reading circuit 204.
|
