| 摘要 |
PURPOSE: An optical pickup device is provided to reduce manufacturing costs and to increase compatibilities, by recording information on a lower disk with an optical beam having a short wavelength after playing back the information with an optical beam having a long wavelength, and by playing back or recording information in an upper disk with the optical beam having the short wavelength. CONSTITUTION: An optical pickup device comprises a long wavelength/low output laser diode, a short wavelength/high output laser diode, a beam combiner/separator, and a numerical aperture controller(60). The long wavelength/low output laser diode plays back information recorded in a lower disk. The short wavelength/high output laser diode records information in the lower disk, and plays back or records information in an upper disk. The beam combiner/separator accords output light of the long wavelength/low output laser diode with output light of the short wavelength/high output laser diode. The numerical aperture controller controls numerical apertures of an optical beam incident to the lower/the upper disks via the beam combiner/separator. |
