Patent ID: 7304935
Filing Date: 2007-12-04
Classification: G11B

Abstract:
1. An optical pickup device comprising: a first light source emitting a light flux with wavelength λ a second light source emitting a light flux with wavelength λ a light-converging optical element having a diffractive structure through which the light flux with wavelength λ a first correcting element having a diffractive structure through which at least the light flux with wavelength λ a second correcting element having a diffractive structure through which at least the light flux with wavelength λ a beam splitter that makes an optical path for the light flux with wavelength λ wherein reproducing and/or recording of information is conducted on the first optical information recording medium having protective substrate thickness t reproducing and/or recording of information is conducted on the second optical information recording medium having protective substrate thickness t at least one of the first correcting element and the second correcting element is arranged between the beam splitter and the first light source or between the beam splitter and the second light source, the first light-converging spot formed on the first optical information recording medium by n an absolute value of chromatic aberration owned by the light-converging optical element itself is controlled to be 0.15 μm/nm or less for the light flux emitted from the first light source, and an absolute value of chromatic aberration owned by the first correcting element itself is controlled to be 2.1 μm/nm or less for the light flux emitted from the first light source.