Patent ID: 6728193
Filing Date: 2004-04-27
Classification: G11B

Abstract:
An optical pickup device comprising:a double-source built-in semiconductor laser array which emits light of a first wavelength and light of a second wavelength; a first divergence modifying device which modifies a diverging rate of the emitted light to a first diverging rate; a second divergence modifying device which modifies a diverging rate of part of the emitted light to be transmitted concentrically; an objective lens which focalizes the light with said first wavelength modified to the first diverging rate by said first divergence modifying device onto a first optical disc, and focalizes the light with said second wavelength modified to a second diverging rate which is determined by said first and second divergence modifying devices onto a second optical disc; a reflected light separating device which separates reflected beams from said first and second optical discs away from the path of the emitted light from said double-source built-in semiconductor laser array; and a detecting device which detects the reflected beams from said first and second optical discs separated by said reflected light separating device, wherein said first divergence modifying device is a collimator lens which converges transmitted light into parallel beams, said second divergence modifying device being a concave lens which spreads part of the emitted light to be transmitted concentrically through said collimator lens, and said objective lens focalizing the light of said first wavelength collimated into the parallel beams by said collimator lens onto a first optical disc and focalizing the light of said second wavelength modified into spread beams which is determined by said collimator lens and said concave lens onto a second optical disc.