Objective lens driving equipment

Abstract

An objective lens driving device used in an optical recording and / or reproduction apparatus comprises a lens holder, elastic supporting members, a coil bobbin and a yoke. An objective lens is mounted in the lens holder. The elastic supporting members have one end attached to the lens holder and the other end attached to a mounting part. The elastic supporting members support the lens holder movably in a direction parallel to the optical axis of the objective lens and in a plane perpendicular to the optical axis. A coil for focusing and coils for tracking are wound on the coil bobbin. A magnet is mounted on the yoke, and the width of this magnet is selected so that flux from the magnet acts only on effective portions of the coils for tracking.

Description

technical field [0001] The present invention relates to an electromagnetically driven actuator for use in an optical pickup for recording signals onto and reproducing signals from an optical recording medium, such as an optical disc or a magneto-optical disc. Background technique [0002] Generally, an optical pickup is used to record and reproduce signals representing information onto and from an information recording medium such as an optical disc, examples of which are so-called compact discs (CD) or magneto-optical discs. The optical pickup includes a semiconductor laser as a light source, an objective lens, an optical system, and a photodetector. [0003] In an optical pickup, a light beam emitted by a semiconductor laser is focused by an objective lens and reaches the recording surface of an optical disc through an optical system. The reflected light beam reflected by the optical disc is separated from the light beam emitted by the semiconductor laser, and this reflec...

AI Technical Summary

Problems solved by technology

[0015] here, as figure 2 As shown, two magnet bodies 7a and 7b are fixed to the inner surfaces of the inner yoke 6a and the outer yoke 6b of the aforementioned yoke 6, and a high magnetic flux density, but there is a problem that the whole biaxial actuator is heavy due to the use of two magnet bodies 7a and 7b

The result is the problem that precise tracking is not possible

[0023] Also, in the biaxial actuator 1 thus constructed, since the yoke bridge 6c is fixed to the open end of the yoke 6 with an adhesive, there is a problem that its adhesive strength is relatively low at about 300 grams to 500 grams, and, for temperature changes, the bond strength decreases greatly when the temperature increases to about 35°C

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