Patent attributes
An optical disk apparatus according to the present invention includes: a rotation driving section on which an optical disk is to be mounted and which drives the optical disk so as to be rotated; a light source; an objective lens for converging light from the light source onto an optical disk mounted on the rotation driving section; a photodetector having at least two detection sections for detecting reflected light, from the optical disk, of the light; and an error signal generation section for deriving a difference signal and a sum signal of respective outputs from the two detection sections of the photodetector, adjusting an offset in at least the sum signal among the difference signal and the sum signal, and thereafter dividing the difference signal by the sum signal whose offset has been adjusted to generate a position error signal of the objective lens.
