| 摘要 |
<p>An integrated optical unit, optical head, and optical recording and/or reproducing apparatus which enables detection of a tracking error signal by the three-beam method by making it possible to write and/or read information to and/or from two types of optical discs using two different wavelength laser beams. The error signal being generated by detecting the return components of the laser beams reflected from the optical discs using a plurality of photodetectors located in the plane of the integrated optical unit. The photodetectors for detecting the first order return components being disposed on an extension of a line connecting a point inside an opening of the package by which a main ray of the first laser emitted from a two-wavelength semiconductor laser passes and a point inside the opening by which a main ray of the second laser passes. <IMAGE></p> |
