Optical disc device and control circuit for optical disc device

Abstract

To prevent the focal point of a light beam from entering an unrecorded area, where no data has been written yet, when data is being read continuously from multiple storage layers. An optical disc drive can read data from an optical disc with at least first and second storage layers. The drive includes: a drive mechanism for rotating the disc; an optical pickup, which irradiates the disc in the drive mechanism with converged light and generates a read signal based on the light reflected from the disc; and a control section for controlling operations of the drive mechanism and the pickup, thereby shifting the focal point of the light. In reading data from the first and second layers continuously, the control section shifts the focal point in a first radial direction while data is read from the first layer and then moves the focal point to a location on the second layer before data starts to be read from the second layer. That location has been shifted from its previous one by a predetermined displacement in a second radial direction that is opposite to the first radial direction.