| 摘要 |
<p>An optical recording apparatus for writing and reading data by applying laser beams onto an optical recording medium through an optical head, wherein the head is provided with a diffraction grating to have a plurality of laser beams generated and some of the laser beams are directed to track guides on the optical recording medium, whereas the remaining laser beams are directed to the other track guides to dispose a plurality of sets of tracking beams. A tracking error signal resulting from a difference in reflected luminous energy is applied to an optical detector for receiving the tracking beams reflected from the optical recording medium. There is also provided a tracking detection circuit for switching the tracking beams. The provision of the plurality of sets of tracking beams contributes to the improvement of tracking reliability even if the tracking guide is defective, because the tracking beam can be switched to another for tracking purposes.</p> |
