摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical head in which signal acquisition quality can be improved by reducing occurrence of interference between codes of the optical disk, while output of a data signal and a control signal can be acquired sufficiently without increasing output of a laser light source, and which has high reliability. <P>SOLUTION: The optical head A has a semiconductor laser light source 1, a collimator lens 2, a beam splitter 3, an objective lens 5, a detecting lens 6, and a photodetecting element 7, and is provided with a diffraction grating 4 in which a second grating part having a high ratio of a 1st order diffraction light is held between two first grating parts having a high ratio of 0th order diffraction light in the diffraction light on the same plane. <P>COPYRIGHT: (C)2007,JPO&INPIT |