| 摘要 |
PROBLEM TO BE SOLVED: To control a position of a lens stably with respect to an optical disk formed so that regions of tracks with different track pitches are mixed, in a three-beam type optical information recording/reproducing device. SOLUTION: When a lens position signal LP is used to perform a long jump operation, a control device 19 controls a signal switch 20 to be on an output side of a lens position signal calculating circuit 18 and sets a gain k provided to a sum signal Ps at a variable gain amplifier 16 to a gain k2 which is optimal for the lens position signal. As a method for determining the gain k2, the amplitudes of a signal Pm generated from a light reception signal of a reflective light of a main spot and a sum signal (Ps1+Ps2) generated from a light reception signal of a reflective light of a subspot are each measured, and k2 which satisfies Pm=k2(Ps1+Ps2) is searched, thereby preventing a tracking error component from remaining in the lens position signal in regions with different track pitches upon a long jump. COPYRIGHT: (C)2009,JPO&INPIT
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