Patent ID: 8537650
Filing Date: 2013-09-17
Classification: G11B

Abstract:
1. An optical read/write apparatus with the ability to write data on a track on an optical storage medium and read the data that has just been written on the track in parallel, the apparatus comprising: a light source; an optical modulator configured to provide the light source with a write modulation signal that modulates the emission power of the light source according to the data to be written; a light-splitting element configured to split a light beam emitted from the light source into multiple light beams including a write beam and a read beam; an optical system configured to converge the write and read beams onto the same track on the optical storage medium so that while a write operation is being performed, the same location on the optical storage medium is scanned with the write beam before being scanned with the read beam; a photodetector including a light receiving element configured to detect the read beam reflected from the optical storage medium and output an electrical signal; a waveform predicting section configured to generate a predicted read waveform by performing processing that includes the step of delaying either the waveform of the write modulation signal or a waveform representing the write modulated component of the light beam that has been modulated with the write modulation signal; a comparing section configured to compare a waveform based on the output of the light receiving element to the predicted read waveform, thereby determining whether or not the data has been written successfully; and a delay detecting section configured to detect the time delay of a waveform representing the output signal of the light receiving element with respect to either the waveform of the write modulation signal or the waveform representing the write modulated component of the light beam that has been modulated with the write modulation signal, thereby controlling the amount of delay caused by the waveform predicting section based on the time delay detected.