Patent ID: 7492684

Claim:
A method for controlling a tilt between an optical axis of an optical pick-up head and an optical disc, applied in an optical disc drive, the method comprising: receiving a trapezoidal-wave signal in a radio frequency signal, wherein the trapezoidal-wave signal comprises a rising edge and a falling edge; calculating a slope sum, wherein the slope sum is a sum of the slope of the rising edge and the slope of the falling edge; generating a tangential tilt control parameter by inquiring a tangential tilt characteristic function according to the slope sum; and controlling the optical disc drive according to the tangential tilt control parameter; wherein the tangential tilt characteristic function is generated by steps comprising: determining a plurality of target values of target tangential tilt control parameters corresponding to a plurality of target tangential-direction tilts; respectively controlling the optical disc drive according to the target values of the target tangential tilt controlling parameters, and receiving a plurality of corresponding target trapezoidal-wave signals outputted by the optical pick-up head, wherein each target trapezoidal-wave signal results from one of the target values and comprises a target rising edge and a target falling edge; calculating a plurality of target slope sums, wherein each of the target slope sum is the sum of a slope of the target rising edge and a slope the target falling edge of the corresponding target trapezoidal-wave signal; and generating the tangential tilt characteristic function according to the target values of the target tangential tilt control parameters and the corresponding target slope sums.