| 摘要 |
The optical head uses the semiconductor laser beams optically mixed together to scan the optical disc. The mixed laser beams are converged onto a tracking guide of a recording surface by an objective lens. The reflected laser beams from the recording surface are separated into the recording reproducing and guiding laser beams by a beam separator. The recording and guide laser beams are shielded in the beam separator and only the reproducing laser beam is directed to photodetecting regions of information, tracking error and defocus detectors.
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