Patent ID: 8000187

Claim:
An optical disc device comprising: an optical pickup which irradiates an optical disc with light and detects returned light from the optical disc by a photo detector; a movable lens for correcting spherical aberration which is arranged in an optical system of the optical pickup; a focus error signal generating part which generates a focus error signal by processing an electric signal output from the photo detector; a tracking error signal generating part which generates a tracking error signal by processing an electric signal output from the photo detector; a movable lens position adjusting part which performs control to adjust position of the movable lens; a focus balance adjusting part which performs control to adjust a focus balance value that is a balance value of an S character curve of the focus error signal; an amplitude detecting part which detects amplitude level of the tracking error signal; a memory portion which stores an inclination α obtained in advance from a graph with either one of the position of the movable lens and focus balance value as a horizontal axis and the other as a vertical axis, the graph showing lines of equal amplitude levels of the tracking error signal, the inclination α being an inclination of a major axis of the equal level lines, each of which is an approximate ellipse, with regard to the horizontal axis; a first searching part which searches a condition where the amplitude level of the tracking error signal is made maximum by changing either one of the position of the movable lens and the focus balance value in a state where a focus servo control is performed based on the focus error signal; an adjusting line setting part which sets an adjusting line that has the inclination α and passes the position of the movable lens and the focus balance value both of which are searched by the first searching part; and a second searching part which changes the position of the movable lens and the focus balance value to plural values on the adjusting line in a state where the focus servo control is performed consecutively to search a condition where the amplitude level of the tracking error signal is made maximum.