Patent ID: 7266074

Claim:
An optical disc apparatus for eliminating an error from a wobble signal and for addressing using the wobble signal, the apparatus comprising: a light division and detection device to divide a light beam projected onto an optical disc and reflected by the optical disc, into at least four light regions in a direction corresponding to a radial direction of the optical disc, and to detect the light regions; and a signal processing unit to detect a first difference signal by performing a subtraction on detection signals for inner light regions of the detected light beam, to detect a second difference signal by performing a subtraction on detection signals for outer light regions of the detected light beam, and to detect the wobble signal by performing a subtraction on the first and second difference signals after applying a predetermined gain to the first and second difference signals, wherein the wobble signal is prevented from being degraded due to cross-talk from wobbles of adjacent tracks on the optical disc, wherein the signal processing unit comprises: a first subtracting operator to perform subtraction on detection signals for the inner light regions of the divided and detected regions to obtain the first difference signal; a second subtracting operator to perform subtraction on detection signals for the outer light regions of the divided and detected regions to obtain the second difference signal; a third subtracting operator to perform subtraction on the first and second difference signals to obtain the wobble signal; and a gain adjuster to apply a predetermined gain to the first and second difference signals, wherein the signal processing unit detects the wobble signal by performing the subtraction of the first and second difference signals after applying the predetermined gain to the first and second difference signals, wherein the wobble signal detected by the signal processing unit is represented by the following equation: wobble signal=ζ·( s 3- s 4)−ζ·( s 1- s 2) wherein ζ is the predetermined gain applied by the gain adjuster to the first and second difference signals when the first difference signal denotes as s 1 −s 2 and the second difference signal denotes as s 3 −s 4 .