Patent ID: 7170834

Claim:
A method of detecting a playback signal using a photodetector which multi-divides an optical signal reflected from an optical recording medium for detection, the method comprising: detecting a time difference between first and second signals derived from the photodetector and temporally matching the first and second signals to compensate for the time difference; and summing the matched signals to provide the playback signal, wherein: the first signal results from detecting information along a first tangential line of the optical recording medium and the second signal results from detecting information along a second tangential line of the optical recording medium; and the detecting of the time difference and the temporally matching comprises: temporally shifting the second signal according to a time delay compensation signal, subtracting the temporally shifted second signal from the first signal to provide a subtraction result, detecting a peak signal of a band corresponding to data of a predetermined period from the subtraction result, and determining a minimum value of the peak signal, a current value of the peak signal and a difference between the peak signal minimum value and the current signal peak value to provide the time delay compensation signal based on the difference.