It is an object of this invention to increase the rigidity of a movable part and decrease its weight. An objective lens driving apparatus has an objective lens which focuses light on the recording surface of an optical disk. The objective lens is driven by focusing coils in directions approaching and receding from the optical disk and is driven by tracking coils in the radial direction of the optical disk. The objective lens is held by a lens holder. A projecting part projecting outward from the outer side surfaces of the lens holder is formed around the entire peripheral edge of the bottom surface of the lens holder.

According to the invention, techniques for minimizing power consumption in optical disk drives. Embodiments according to the present invention can provide disk drives with optimal positioning of a fixing part of an objective lens driving unit incorporated therein. Spatial location of magnets can also be determined in order to reduce the power consumption and the torsion of the lens.

A bias magnet unit has a permanent magnet that applies a bias magnetic field to an optical spot on a magneto-optical disk. A driving coil rotates the magnet in order to change a polarity of the bias magnetic field. A sensor detects the intensity and polarity of the bias magnetic field to confirm the rotational position of the magnet after it has been rotated. A linkage structure that is connected between a magnet holder of the magnet unit and the housing has arms that drive the magnet unit between two positions, one in which the magneto-optical disk cartridge can be inserted into the device and another in which the disk is loaded onto the spindle motor for recording/playback. Overall, the components of the device cooperate structurally to provide a relatively thin device structure having low power consumption.

An optical head for a recording device in which data are recorded on a recording surface of an optical memory disk, comprises, a head body which is substantially prevented from moving perpendicularly to the recording surface and is movable to be positioned roughly along the recording surface, an object lens for focussing a light beam on the recording surface, a carriage on which the object lens is mounted and which is movable to be positioned precisely along the recording surface, a drive base member for generating a force substantially parallel to the recording surface between the drive base member and the carriage to position precisely the carriage along the recording surface, and an elastic member for connecting the drive base member to the head body to support the drive base member relative to the head body elastically in a direction substantially parallel to the recording surface, joining areas between the elastic member and the drive base member and between the elastic member and the head body are aligned substantially straightly.