Patent ID: 7215607
Filing Date: 2007-05-08
Classification: G11B

Abstract:
1. An optical disc apparatus for recording or playing back optical information on an optical disc, comprising: a convergence lens for converging an optical beam onto the optical disc; a light detection device, including a first detection portion and a second detection portion, operable to receive and detect the optical beam reflected by the optical disc on each detection portion in a tracking direction, and output a first detection signal corresponding to a detected result from either one of the detection portions and a second detection signal corresponding to a detected result from the other detection portions; a lens shifting unit operable to shift the light receiving area of the light detection device in a tracking direction by shifting the convergence lens in the tracking direction; an amplifying unit operable to change a gain balance by amplifying the first and the second detection signals using independent gains respectively; an addition unit operable to output an addition signal by adding the first detection signal to the second detection signal in response to the shift in lens position of the convergence lens and the change in gain balance made by the lens shifting unit and the amplifying unit; and a gain balance adjustment unit operable to obtain the addition signal outputted from the addition unit, specify a gain balance that equalizes detection sensitivities of the respective detection portions in the light detection device based on the obtained result, and control the amplifying unit so as to have the amplifying unit amplify the first and the second detection signals using the specified gain balance.