| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical path correcting device for obtaining fixed transmission light to a monitor photo detector regardless of the wavelength of laser beams, and an optical pickup using the optical path correcting device. <P>SOLUTION: The optical path correcting device 14 comprises a first wavelength plate 5, a birefringent plate 2, and a second wavelength plate 15, and is arranged in front of a 2-wavelength laser 6. The first wavelength plate 5 rotates the polarization direction of only one laser beam L2 emitted from the 2-wavelength laser 6 by 90° so that laser beams L1 and L2 have mutually orthogonal polarization directions. The birefringent plate 2 is composed so that its optical axis coincides with the polarization direction of one laser beam L2, and the laser beams L1, L2 are propagated in the same optical path. The second wavelength plate 15 rotates the polarization direction of only one laser beam L2 transmitted through the birefringent plate 2 by 90° so that the laser beams L1, L2 become linear polarization having the same polarization direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
