Patent ID: 8488426
Filing Date: 2013-07-16
Classification: G11B

Abstract:
1. A disc device for recording or reproducing information data on or from an optical recording medium, the optical recording medium including a tracking guide layer in which a guide track for tracking is formed and at least two recording layers in which information data is recorded, the device comprising: a first light source configured to generate a first laser light for reproducing or recording the information data on or from the recording layer, and positioned such that the first laser light forms a first ellipse-shaped spot on the recording layer, with the first ellipse-shaped spot having a major axis; and a second light source configured to generate a second laser light for reading the guide track from the tracking guide layer, and positioned such that the second laser light forms a second ellipse-shaped spot on the tracking layer, with the second ellipse-shaped spot having a major axis, and a direction of the major axis of the first ellipse-shaped spot differing from a direction of the major axis of the second ellipse-shaped spot, so that an amplitude of a push-pull signal in a push-pull system is increased.