Patent ID: 7020053
Filing Date: 2006-03-28
Classification: G11B

Abstract:
1. An optical disc apparatus comprising: an optical pickup for emitting a light beam to the optical disc, receiving a reflected light from a data recording face of the optical disc, converting variation of intensity of the reflected light to electric signals and outputting the electric signals; a driving mechanism for moving the optical pickup in a radial direction of the optical disc; a signal processor for generating intensity signals of the reflected light, focusing error signals and tracking error signals corresponding to the signals outputted from the optical pickup; a data slice signal generator for generating data slice signals generated by digitalizing the intensity signals of the reflected light outputted from the signal processor; a focusing servo controller for focusing the light beam emitted from the optical pickup on the data recording face of the optical disc corresponding to the focusing error signals outputted from the signal processor; a tracking servo controller for tracking the light beam on a data recording track on the optical disc corresponding to the tracking error signals outputted from the signal processor; and a main processor for controlling an initial reading operation so as to read out information data recorded in the innermost data recording area on the optical disc; wherein in the initial reading operation, the main processor controls the driving mechanism so as to place the optical pickup at an initial reading position outwardly distant a predetermined distance from the innermost edge of the innermost data recording area on the optical disc, at the start; the main processor senses periods between adjoining two pits formed on the optical disc based on the data slice signals outputted from the data slice signal processor while the light beam emitted from the optical pickup is focused on the data recording face of the optical disc by the focusing servo controller at the initial reading position, and compares the periods between the pits with a standard value memorized in a memory; when the periods between the pits are equal to or smaller than the standard value, the main processor judges that the information data are recorded on a data recording track facing the initial reading position of the optical pickup, controls the tracking servo controller so as to track the light beam precisely on the data recording track facing the initial reading position, and reproduces the information data based on the data slice signals obtained from the pits sensed on the data recording track; alternatively, when the periods between the pits are larger than the standard value, the main processor judges that no information data is recorded on a data recording track facing the initial reading position of the optical pickup, controls the driving mechanism so as to move the optical pickup inwardly from the initial reading position, senses periods between the pits formed on the optical disc based on data slice signals outputted from the data slice signal processor while the optical pickup is moved and the light beam is focused on the data recording face of the optical disc, and compares the periods between the pits with the standard value memorized in a memory; when the periods of the pits become equal to or smaller than the standard value, the main processor judges that the information data are recorded on the data recording track facing the optical pickup, controls the tracking servo controller so as to track the light beam precisely on the data recording track, and reproduces the information data based on the data slice signals obtained from the pits sensed on the data recording track; and when the periods between the pits has not become equal to or smaller than the standard value after moving the optical pickup by a predetermined distance inwardly from the initial reading position, the main processor judges the optical disc is a blank disc on which no information data is recorded, and outputs an alarm for showing the optical disc is the blank disc.