| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem that in a conventional optical recording and reproducing apparatus which obtains height of an objective lens in the focal direction in order to correct a tilt, an accurate height cannot be obtained, an error is caused in angle calculation and the tilt is not properly corrected. SOLUTION: For a tilt ACT driver 8, in each of N pieces of different tilt instruction values, on the basis of N pieces of measured values of a focus loop gain or a tracking loop gain measured by a loop gain measuring circuit 15, a tilt instruction value to maximize the measured values of the loop gains is calculated by a first approximate expression. On the basis of a correlation of M pieces of instruction values obtained by the first approximate expression at M pieces of respective positions of an optical disk 1 with the positions of the optical disk 1, a second approximate expression for obtaining an optimum value of the tilt instruction value at a desired position is obtained. The optimum value of the tilt instruction value is derived from the second approximate expression during reproducing or recording, and is set to the tilt ACT driver 8. COPYRIGHT: (C)2008,JPO&INPIT
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