| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a focus error detection device in which the optical axial direction of an optical pickup device does not have to be adjusted, the position adjustment accuracy of light detecting means can be significantly relieved, a FES detection range is wide, and RF signal quality is improved. <P>SOLUTION: The polarizing orientation of a main beam 31 and subbeams 32a and 32b is changed. A combination of a 1/4 wavelength plate 16 and a polarizing beam splitter 13 detects the main beam 31 and the subbeams 32a and 32b on different photodetector surfaces to prevent light of each other from mixing to respective photodetectors. As a result, the range of detecting a focus error signal is expanded, and the signal quality of an information reproduction signal is also improved. <P>COPYRIGHT: (C)2003,JPO |
