Patent ID: 7916596

Claim:
An optical disc device for reading a signal recorded on an optical disc medium, comprising: an optical pickup which selectively applies light having one wavelength, out of a plurality of different wavelengths, to the optical disc medium through one objective lens, and which outputs a signal based on light reflected by the optical disc medium; a drive unit which moves the objective lens of the optical pickup relative to a surface of the optical disc medium; and a control unit which detects a signal based on surface reflection by the surface of the optical disc medium, a fake signal generated based on the surface reflection, and a signal based on light reflected by a data recording layer of the optical disc medium, while the objective lens is moved relative to the surface of the optical disc medium by the drive unit, and which discriminates a type of the optical disc medium based on a ratio of a first time period between an instant when the surface reflection is detected and an instant when the fake signal is detected, and a second time period between the instant when the surface reflection is detected and an instant when light reflected by the data recording layer is detected.