| 摘要 |
PROBLEM TO BE SOLVED: To obtain a device capable of recording and reproducing correctly even optical disks of different systems by allowing the device to have a plurality of object lenses and a semiconductor laser becoming two light sources having different wavelengths corresponding to a plurality of optical disks whose thicknesses of substrates are different. SOLUTION: The light beam emitted from a semiconductor laser 21 is guided to a grating 22 and the incident light is divided into a main beam being a zero order light beam and side beams being ±1st order light beams. A beam splitter 23 is disposed in a state in which a semitransmissive reflection surface 23a is tilted by 45 degrees with respect to an optical axis to separate the light beams from the grating 22 and a return light of the signal recording surface of an optical disk D1 or D2. An object lens 25 is made to be movable in a focusing direction and a trancking direction by a biaxial actuator 30 and has other different two object lenses 25a, 25b. These lenses are suported by a lens holder so as to be alternatively inserted into an optical path. |
