| 摘要 |
PURPOSE:To prevent effectively the generation of rolling resonance without increasing the size of a magnetic circuit by generating a magnetic flux from a magnetic flux generating means to each tracking coil to displace the objective lens in the tracking direction. CONSTITUTION:Focusing coils 53a, 53b and tracking coils 54-57 are mounted in the tracking direction T at both sides of a support member 51 of an objective lens 50 supported by springs 52a, 52b, a couple of permanent magnets 60a, 60b, 61a, 61b are fixed to yokes 58, 59 forming a magnetic circuit to generate a magnetic flux to each coil. A current corresponding to each error value flows to the coils 53a, 53b and the coils 54-57 to change the lens 50 in the focusing direction F and the direction T. Since the currents flowing to the lead extended in the direction T are opposite to each other, when the lens 50 is shifted in the direction F, no moment of inertia is caused and the rolling resonance is prevented effectively.
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