Patent ID: 7391704
Filing Date: 2008-06-24
Classification: G02B,G11B

Abstract:
1. An optical pickup device comprising: a light source to emit light; an objective lens to focus the emitted light from the light source on a recording medium to form a light spot; an optical path changer disposed on an optical path of the emitted light between the light source and the objective lens, the optical path changer changing the optical path of the emitted light; a chromatic aberration correction lens disposed on the optical path between the light source and the objective lens, the chromatic aberration correction lens correcting a chromatic aberration occurring due to a change in a wavelength of the emitted light and/or due to an increase in a wavelength bandwidth of the emitted light, and the chromatic aberration correction lens comprising a first lens facing the light source having a negative power, a second lens adjacent to a surface of the first lens facing away from the light source having a positive power, and a third lens adjacent to a surface of the second lens facing away from the first lens having a negative power, wherein surfaces of the first and third lenses facing the light source and the objective lens, respectively, have positive radii of curvature, a surface between the first and second lenses has a positive radius of curvature, and a surface between the second and third lenses has a negative radius of curvature, and; a photodetector to receive the light reflected from the recording medium and then incident thereon through the optical path changer.