| 摘要 |
PROBLEM TO BE SOLVED: To perform proper reproducing by using a simply structured optical system to irradiate different kinds of optical recording media with laser beams having different wavelengths. SOLUTION: This device is at least provided with first and second light sources for emitting first and second laser beams having polarized planes orthogonal to each laser an objective lens 7 for converging the first and second laser beams on first and second optical recording media, and a light receiving element 9 for receiving return laser beams reflected from the optical recording media. In the emission side of the first and second light sources, a polarization hologram element 30 is disposed for passing both first and second laser beams emitted from the first and second light sources. This polarization hologram element 30 functions as a diffraction grating with respect to the first laser beam and outputs plural beams, and has the characteristic of directly passing the second laser beam. Preferably, a laser beam emission device 20 is provided, which includes the first and second light sources and a polarized beam splitter in a single package. |
