Patent ID: 7843777
Filing Date: 2010-11-30
Classification: G11B

Abstract:
1. A method for assembling an optical pickup apparatus including, a first light source for emitting first light beams having a wavelength of λ a second light source for emitting second light beams having a wavelength of λ a third light source for emitting third light beams having a wavelength of λ a first objective lens, a second objective lens, a lens holder for holding the first objective lens and the second objective lens, an actuator for supporting the lens holder and driving the lens holder, and an actuator base for supporting the actuator, wherein: the first light beams from the first light source are applied to record and/or reproduce information onto/from a first optical information recording medium by converging the first light beams onto an information recording surface of the first optical information recording medium through a protective layer having thickness of t the second light beams from the second light source are applied to record and/or reproduce information onto/from a second optical information recording medium by converging the second light beams onto an information recording surface of the second optical information recording medium through a protective layer having thickness of t the third light beams from the third light source are applied to record and/or reproduce information onto/from a third optical information recording medium by converging the third light beams onto an information recording surface of the third optical information recording medium through a protective layer having thickness of t the optical pickup apparatus is used in an optical information recording-reproducing apparatus having a relative tilt angle changing device for changing a relative tilt angle formed between the optical information recording medium and one of the first and second objective lenses of the optical pickup apparatus; the relative tilt angle changing device is arranged to be able to control a coma aberration associated with light beams converged onto the recording surface of the optical information recording medium by changing the relative tilt angle formed between the optical information recording medium and one of the first and second objective lenses; the first objective lens is designed based on an image height priority design method against the first light beams, the image height design method being a design method for correcting a spherical aberration and a sine condition; and the second objective lens is designed based on the image height priority design method against the second light beams, and a tilt angle priority design method against the third light beams, the tilt angle priority design method being a design method for correcting the spherical aberration while not correcting the sine condition, the method for assembling the optical pickup apparatus comprising the steps of: adjusting a first tilt angle of the actuator base so that a coma aberration of a spot formed by the first light beams decreases when the first light beams are converged onto the first recording medium via the first objective lens, adjusting a second tilt angle formed between the second objective lens and the lens holder which is supported by the actuator base through the actuator so that a coma aberration of a beam spot formed by the second light beams decreases when the second light beams are converged onto the second recording medium via the second objective lens; and conducting a shift adjustment process for the third light source so that a coma aberration of a beam spot formed by the third light beams decreases when the third light beams are converged onto the third recording medium via the second objective lens.