| 摘要 |
<p>An apparatus for detecting tracking errors of an optical head, wherein a laser beam from a semiconductor laser element (1) is permitted to be incident upon a diffraction grating (3), a zero-order beam and ↓∃ primary beams from the diffraction grating (3) are permitted to be incident upon an object glass (5) via a beam splitter (4), the zero-order beam and ↓∃ primary beams that fall focused on an optical recording medium (6) are that are reflected thereby, pass through the object glass (5), are further reflected by the reflecting surface of the beam splitter (4), and are permitted to be incident on a light detector (7) which produces a pair of outputs corresponding to ↓∃ primary beams, in order to obtain a tracking error signal of the zero-order beam which corresponds to the tracking condition on the optical recording medium (6) based upon the difference between the above-mentioned pair of outputs. In this apparatus, provision is made of a light attenuating means in an optical path between the semiconductor laster element (1) and the optical recording medium (6), in order to attenuate the laser beam reflected by the beam emitting end face (1A) of the semiconductor laser element (1), the reflected beam being produced by the beam which returns from the optical recording medium (6). This makes it possible to reduce disturbance to the tracking error signals caused by the change in the tangential skew angle of the optical recording medium (6).</p> |
