Optical disc apparatus and method for determining information recording layer in optical disc

Abstract

An optical disc device includes a laser diode which irradiates an optical disc having a plurality of layers with laser light, a photodetection section which detects laser light reflected by the optical disc, which comprising a pair of sub-photodetectors and a main photodetector provided between the pair of sub-photodetectors, a focus error signal generation circuit which generates a focus error signal from a photodetection signal output by the main photodetector, a tracking error generation circuit which generates a tracking error signal from the photodetection signal output by the main photodetector and a photodetection signal output by the pair of sub-photodetectors, and a layer determination signal processing circuit which generates a layer determination signal from the photodetection signal output by the pair of sub-photodetectors and determines in which of the layers a focus of the laser light is located, on the basis of the layer determination signal and focus error signal.

Dependencies are inferred from the claim text.