Patent ID: 7158455

Claim:
A servo error detector for an optical disk having a signal recording side, comprising: an optical detector for receiving light reflected from the signal recording side of the optical disk in multiple light receiving regions and generating electric signals corresponding to the light intensity of the reflected light in each of the light receiving regions, an envelope detector for detecting the top envelope and bottom envelope of each of the electric signals and generating a top envelope signal and a bottom envelope signal for each of the electric signals, and a servo error signal generator circuit for processing the top envelope signals and bottom envelope signals to generate a servo error signal, wherein the servo error signal generating circuit calculates the difference between the bottom envelope signal obtained from a first light receiving region and the bottom envelope signal obtained from a second light receiving region to generate an alignment signal, calculates the difference between the top envelope signal obtained from the first light receiving region and the top envelope signal obtained from the second light receiving region to generate a top envelope difference signal, calculates the difference between the alignment signal and the top envelope difference signal to generate a first difference signal, equalizes the alignment signal, and combines the first difference signal and the equalized alignment signal to generate the servo error signal.