Patent ID: 6477129
Filing Date: 2002-11-05
Classification: G11B

Abstract:
An optical disc drive capable of recording/reproducing data to/from an optical disc, said optical disc being either one of a first disc and a second disc, a protective layer of said first disc being thinner that that of said second disc, comprising:a first laser diode that emits a first laser beam having a first wavelength; a second laser diode that emits a second laser beam having a second wavelength, said second wavelength being longer than said first wavelength; an objective lens that converges the first laser beam on said first disc, and the second laser beam on said second disc; and a driving unit that holds and rotates said optical disc, an optical axis of said objective lens being inclined relative to a normal to said optical disc, a beam emitting point of said first laser diode being located at a first position, coma, which is caused when the first laser beam is converged on a data recording surface of said first disc, being minimized when said first laser beam is emitted from said first position, and a beam emitting point of said second laser diode being located at a second position which is different from said first position, wherein coma, which is caused when the second laser beam is converged on a data recording surface of said second disc, is minimized when said second laser beam is emitted from said second position.