| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup device having a different optical path length for each optical system corresponding to each different recording medium while using a two wavelengths laser unit. <P>SOLUTION: A first laser beam is reflected by a polarizing beam splitter 6 and also the polarization light direction of each of first and second laser beam is set so as to transmit the second laser beam, and a first reflection mirror 9 is arranged so that the first laser beam reflected by the polarizing beam splitter 6 is returned to the same optical path and also a first 1/4 wavelength plate 10 is arranged this side of the first reflection mirror 9 for polarizing the laser beam by 1/4 wavelength, and a second reflection mirror 11 is arranged facing oppositely to the first reflection mirror 9 while holding the polarizing beam splitter 6 between them and also a second 1/4 wavelength plate 12 is arranged this side of the second reflection mirror 11 for polarizing the laser beam by 1/4 wavelength. Thus, the first laser beam is advanced toward an objective lens 8 after reciprocated between the first reflection mirror 9 and the second reflection mirror 11. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
