1. Field of the Invention
The present invention relates to an optical device applied to an optical disk drive apparatus to serve as an optical pickup device for optically recording/ reproducing information on/from an optical disk medium.
2. Description of the Related Art
An optical pickup device for recording/reproducing information on/from an optical disk medium by irradiating the medium with a focused minute laser spot, comprises a minute-movement mechanism for automatically adjusting a position of the optical pickup device relative to the optical disk medium and a rough-movement mechanism for greatly moving the optical pickup device to a target position of the optical disk medium at high speed. Since the rough-movement mechanism requires a precise guide mechanism, a sliding bearing is widely used therefor. The sliding bearing has the advantage of relatively low cost, high productivity, and moderate dumping effect; therefore, it can be widely used as a guide for the rough-movement mechanism of the optical pickup device.
However, the sliding bearing has a drawback in which its frictional resistance is higher than that of a bearing and becomes much higher if it is used for a long period of time. The high frictional resistance of the sliding bearing is a great hindrance to improvement in access characteristics.