Patent ID: 7936656
Filing Date: 2011-05-03
Classification: G11B

Abstract:
1. An optical disc apparatus for recording or reproducing recording marks by irradiating a first light emitted from a light source and a second light having a wavelength different from the first light onto an optical disc by way of an objective lens, the apparatus comprising: an objective lens drive section that drives the objective lens for focusing the first light in a reflection/transmission layer formed on the optical disc and adapted to reflect the first light and transmit the second light according to the first light reflected by the reflection/transmission layer; a focus moving section that moves a focus of the second light in a direction of an optical axis thereof by way of displacement of itself along the optical axis of the second light to make the focus of the second light agree with a target depth of the optical disc to be irradiated by the second light; and a focus movement control section that displaces the focus moving section by a quantity of displacement corresponding to the target depth from a reference position in order to move the focus of the second light to the target depth; the focus movement control section being adapted to focus the second light on a reflection region formed on part of the reflection/transmission layer to reflect both the first light and the second light according to the second light reflected by the reflection region in a state where the first light is focused on the reflection region and define a position of the focus moving section at a time of the focusing of the second light as reference position.