| 摘要 |
PROBLEM TO BE SOLVED: To record/reproduce plural kinds of optical disks such as the optical disks with information recording surface positions different from each other in the thickness direction and the optical disk with wavelength dependency, etc., by the same optical pickup and to discriminate the kind of the optical disk in a short time. SOLUTION: The optical pickup is constituted of two or above of laser diodes 1, 1a with different emission wavelengths, an objective lens 2 converging bundle of rays outgoing from them on the information recording surfaces 8, 8a, a dichroic coated filter 10, photodiodes 5, 5a signal converting return light reflected by the information recording surface and a prism 3 refracting the ray flux outgoing from the laser diodes 1, 1a. When the kind of the optical disk is discriminated, the objective lens 4 is moved in the optical axial direction while light emitting the laser diodes 1, 1a, and when information is recorded/ reproduced, only the laser diode matched with the loaded optical disk is light emitted. |
