Patent ID: 8446802

Claim:
An optical drive device comprising: a first light source; a second light source; an objective lens configured to receive a first light emitted from the first light source and a second light emitted from the second light source and to irradiate both the first light and the second light to an optical disc recording medium; a first focus mechanism configured to drive the objective lens in a focus direction; a second focus mechanism configured to change collimation of the second light incident to the objective lens and changing the focusing position of the second light independently of the first light; a first focus servo control unit configured to drive the first focus mechanism based on a first focus error signal obtained by receiving the reflected light of the first light so as to perform focus servo control of the first light; an error signal subtraction unit configured to subtract the first focus error signal from a second focus error signal obtained by receiving the reflected light of the second light; and a second focus servo control unit configured to drive the second focus mechanism based on the second focus error signal subjected to the subtraction by the error signal subtraction unit so as to perform focus servo control of the second light.