发明授权
US5671200A Method for detecting the movement of a light beam and optical information reproduction apparatus using the same 失效
用于检测光束的移动的方法和使用其的光学信息再现装置

Method for detecting the movement of a light beam and optical
information reproduction apparatus using the same
摘要:
An optical information reproduction apparatus for reproducing information from a disc having a plurality of tracks storing the information in the form of pits includes a radiation device for radiating a light beam toward the disc to form a light spot on the disc; a moving device for moving the radiation device to move the light spot in a direction crossing the plurality of tracks in a radial direction of the disc; a photodetector having a detecting plane for receiving the light beam reflected by the disc, the detecting plane being divided into four detection areas at least in a direction parallel to a tangent of the tracks and in a direction perpendicular to the tangent of the tracks, the four detection areas generating light intensity signals corresponding to the intensities of the light beam which is received; a positional offset detector for detecting a positional offset of the light spot with respect to one of the tracks based on the light intensity signals generated by the photodetector and outputting the detection result as a positional offset signal; a signal processor for performing processing of the light intensity signals including logic operation to obtain an operation signal; and a direction detector for detecting a direction in which the light spot moves with respect to a target track based on the positional offset signal and the operation signal during the movement of the light spot toward the target track.
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