Patent ID: 6434094
Filing Date: 2002-08-13
Classification: G11B

Abstract:
An optical disk apparatus for reproducing information recorded on an information face of a disk using an optical head having a first focal point for reproducing a disk having a thick base substrate and a second focal point for reproducing a disk having a thin base substrate, said apparatus comprising:a focal point moving device operable to move the first and second focal points in a direction perpendicular to the information face of the disk; a reflected light detecting device operable to detect a reflected light from the disk; a focus error detecting device operable to detect a focused state of a light beam irradiating the information face of the disk on the basis of an output signal from said reflected light detecting device; a focus control device operable to control focusing so that the focused state of the light beam becomes a desired state, on the basis of an output signal from said focus error detecting device; and a generating device operable to generate a timing signal for driving said focus control device on the basis of an output signal from said focus error detecting device; wherein said focal point moving device is driven so that the focal points go away from the disk, and said focus control device is operated in response to the timing signal; and when no information is reproduced, said focus control device is immobilized, and said focal point moving device is driven so that the focal points approach the disk, and said focus control device is operated in response to the timing signal.