Patent ID: 7646691

Claim:
An optical disc apparatus that recognizes a surface of an optical disk as a recording side or a label side, which optical disk includes a recording layer on which a groove is formed toward the recording side, a reflective layer positioned between surfaces of the recording side and the label side and provided closer to the surface of the label side than the other, and a discolorable layer which may be discolored by heat or light and provided on the label side, the apparatus comprising: an irradiating unit which irradiates, with a laser beam, one of the surface of the recording side and the label side; a focusing unit which drives an objective lens along the optical axis for focusing the laser beam at a focal point; a focus searching unit which control the focusing unit so that the focal point moves up and down in a predetermined range; an error signal outputting unit which outputs a focus error signal indicating in which direction and to what extent the focal point is deviated from the reflective layer of the optical disk; and a discriminating unit which acquires a S-curve waveform of the focus error signal that appears when the focal point of the laser beam passes through the reflective layer due to up and down motion of the focal point, and discriminates the recording side faces toward the irradiating unit when the S-curve waveform in the focus error signal is a single S curve waveform and discriminates the label side faces the irradiating unit when the S-curve waveform in the focus error signal is a double S curve waveform.