Seiko Instruments Inc

Seiko Instruments & Electronics Ltd.

Shinji Wakui

Hideo Hoshi

Ikuo Nanno

Seiji Hoshi

Yasuaki Morimoto

A control device for controlling displacement of a magnetically supported moving member according to a command. A feedback circuit detects the displacement of the moving member to servo-control the same to thereby ensure stability and robustness of magnetic supporting. A feedforward circuit has an input terminal receptive of a command and an output terminal connected to the feedback circuit, and cooperates with the feedback circuit while not disturbing the stability and robustness of the magnetic suppporting for controlling the displacement of the moving member according to the command.

Control system for magnetic bearing

An objective lens apparatus for an optical disc player comprises an objective lens holder rotatable about a center axis, an objective lens carried by the holder at a location spaced from the center axis, an optical member, a magnetic flux generating member for generating magnetic flux, and tracking and focusing coils interacting with the magnetic flux for effecting tracking and focusing adjustments of the objective lens. The optical member rotates simultaneously with the lens holder and leads light which is incident along the center axis to the objective lens in a direction parallel to the center axis thereby eliminating optical modulation of the light caused by rotation of the lens holder in the tracking direction.

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Tokyo, Japan

Shinji Wakui