| 摘要 |
PURPOSE:To access lots of recording information of plural laminated optical disks in a short access time by reflecting only the laser beam of a specific wavelength with a dichroic mirror, making the light incident on an opposed optical pickup and using a light source and a detection section in common. CONSTITUTION:In selecting a disk face 5d, the wavelength of a light source 1 is matched to a wavelength lambdad reflected by the dichroic mirror 3d. If there are equal wavelengths among reflection wavelengths lambdaa, lambdab, lambdac, lambdad of dichroic mirrors 3a, 3b, 3c, 3d, since the light does not reach a position far from the light source 1, the wavelengths lambdaa, lambdab, lambdac, lambdad of the laser beam emitted from the light source 1 should be different from each other. The laser beam L is collimated by the light source 1 and the effect of the selection/changeover of a disk face 5 and the radial movement of the optical pickup 4 is avoided. Further, an eye laser forming semiconductor lasers with different oscillation wavelengths on one chip is used for the light source 1 and the light is collimated by a collimator lens. |
