| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize a compact optical system using a wavelength selection type polarization beam splitter in a three wavelengths optical system. <P>SOLUTION: This optical pickup is provided with first to third light sources emitting laser beams of the first to third wavelengths, a photodetector receiving the laser beams of the first to third wavelength reflected by an optical disk 2, objective lenses 19, 20 converging the laser beams of the first to third wavelengths on a signal recording plane of the optical disk 2, a collimate means 14 converting the divergent laser beams of the first to third wavelengths to almost parallel light, while converting the laser beams reflected by the optical disk 2 to converged light forward the photodetector, and a wavelength selection type polarization beam splitter 12 arranged in a divergence and convergence optical path in which the laser beams of the first to third wavelengths pass through commonly between the first to third light sources or the photodetector and the collimate means 14, whereas the wavelength selection type polarization beam splitter 12 transmits the laser beams of the first and second wavelengths independently of a polarization state, and transmits or reflects the laser beams of the third wavelength in accordance with a polarization state. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
