Patent ID: 7499388

Claim:
An optical disc apparatus for recording information onto an optical disc, comprising: an optical head device including a laser light emitting unit configured to radiate laser light onto said optical disc, and a light detection unit illuminated by return light of the radiated laser light and configured to generate an electrical signal containing information components obtained from said optical disc based on the return light; and a signal processing circuit configured to perform control for reproducing signals recorded on said optical disc or for recording signals onto said optical disc responsive to the electrical signal output from said optical head device; said light detection unit including: a photoelectric converter unit divided into at least two portions along a direction corresponding to the radial direction of said optical disc; a multiplication circuit configured to multiply an electrical signal, generated by one of said two portions of the photoelectric converter unit, obtained by division in a direction corresponding to the radial direction of said optical disc, with a coefficient t; and a differential circuit configured to calculate a difference between an electrical signal generated by the other of said two portions of the photoelectric converter unit obtained by division in the direction corresponding to the radial direction of said optical disc, and the electrical signal output from said multiplication circuit, to generate a radial push-pull signal, wherein said coefficient t is set to a value corresponding to a ratio of an average value of an electrical signal by return light illuminating said one of said two portions of said photoelectric converter unit and an average value of an electrical signal by return light illuminating said other of said two portions, or a ratio of said average value, sampled at a preset timing, of said electrical signal by return light illuminating said one of said two portions, and said average value, sampled at a preset timing, of said electrical signal by return light illuminating said other of said two portions, and wherein said signal processing circuit adjusts said coefficient t responsive to an error rate of a signal contained in boundary components of a recording track of said optical disc.