Patent ID: 8040764
Filing Date: 2011-10-18
Classification: G11B

Abstract:
1. An optical disc apparatus comprising: an optical disc; an objective lens that converges a light beam emitted from a light source and irradiates the optical disc having recording marks formed as bubbles in a uniform recording layer with the light beam, the bubbles being formed between upper and lower portions of the uniform recording layer, the upper portion of the uniform recording layer being closer to a first side of the optical disc than the bubbles, the lower portion of the uniform recording layer being farther from the first side than the bubbles, the first side of the optical disc being a side upon which the light beam is incident on the optical disc from the objective lens; a detection signal generation section that receives a return light beam reflected from the recording marks and generates a detection signal; a servo control signal generation section that generates a servo control signal representing relative displacement between the recording marks and a focus of the light beam at least partially based on the detection signal; and a servo signal correction section that generates a correction servo control signal by connecting peaks of the servo control signal, the peaks being produced according to the recording marks.