Patent ID: 8027229

Claim:
A focus control device which performs a focus control when write-in or readout of data is performed using an optical pickup to an optical disc on which a land area and a groove area are continuously formed, comprising: a land area focus learning unit which determines a first focus position in the land area, and generates a first focus position signal, and determines a land-area jitter curve; a groove area focus learning unit which determines a second focus position in the groove area, and generates a second focus position signal, and determines a groove-area jitter curve; a switching area focus position calculation unit which determines a third focus position, in an area where the land area and the groove area are switched, based on an intersection of the land-area jitter curve and the groove-area jitter curve, and generates a third focus position signal; a switching signal generation unit which generates a switching signal whose polarity is inverted at the switching between the land area and the groove area; a focus position control unit which adjusts the focus of the optical pickup to the first focus position when the switching signal indicates the land area, and adjusts the focus of the optical pickup to the second focus position when the switching signal indicates the groove area; and said focus position control unit moving the focus position of the optical pickup to the third focus position when the switching signal is inverted in accordance with the switching between the land area and the groove area.