| 摘要 |
PROBLEM TO BE SOLVED: To easily and inexpensively adjust the focus position of an objective lens in a short period of time without complicating the configuration of an optical disk inspection device, in the optical disk inspection device using an ultraresolution proximate field structure. SOLUTION: An optical disk inspection device is provided with a noise extraction circuit 45 for detecting that a noise component contained in a reflected light from an optical disk DK reaches a predetermined amount or more, an envelope curve circuit 46, an envelope curve level detection circuit 47, and a focus pulling signal generation circuit 44 for continuously displacing an objective lens 25 within a displaceable range in an optical axis direction. The objective lens 25 is continuously displaced in the optical axis direction based on a synchronous signal in the state of inhibiting focus servo control, and the position of the objective lens 25 is set as a focus position when the noise component contained in the reflected light form the optical disk DK reaches the predetermined level or more. COPYRIGHT: (C)2006,JPO&NCIPI
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