Patent ID: 7366069
Filing Date: 2008-04-29
Classification: G11B

Abstract:
1. An auto-adjusting system for an optical incident angle in an optical information recording/reproducing apparatus, the optical information recording/reproducing apparatus comprising a pickup head and a tilt actuator, the pickup head generating a laser beam to read data from a recording block of a first radius on a compact disc and receive a focus output voltage (FOSO) in responsive to the reflected laser beam, the tilt actuator outputting a tilt adjusting signal to correct the inclination of the pickup head, so as to keep the laser beam at a predetermined optical incident angle to read data from the compact disc, the auto-adjusting system comprising: a memory for storing a linear tilt compensation table and a non-linear tilt compensation table, the linear tilt compensation table being built via a predetermined linear tilt adjusting procedure and comprising a plurality of focus output voltages and a plurality of corresponding linear tilt dac values, the non-linear tilt compensation table recording a plurality of non-linear tilt compensation parameters, each non-linear tilt compensation parameter being a function of the first radius and a second radius wherein the compact disc begins to generate non-linear deformation; a linear tilt calculation unit, for calculating the corresponding linear tilt dac value by consulting the linear tilt compensation table according to the first radius and the focus output voltage; a non-linear tilt calculation unit, for generating the second radius wherein the compact disc begins to generate non-linear deformation according to a predetermined comparison procedure, and then obtaining the corresponding non-linear tilt compensation parameter by consulting the non-linear tilt compensation table according to the first radius and the second radius; and a controller for controlling the pickup head, the memory, the linear tilt calculation unit, and the non-linear tilt calculation unit; wherein, when the pickup head reads data from the recording block on the compact disc, the controller controls the calculation of a tilt compensation equation by inputting the linear tilt dac value generated by the linear tilt calculation unit and the non-linear tilt compensation parameter generated by the non-linear tilt calculation unit, and enables the tilt actuator to output the corresponding tilt adjusting signal to the pickup head according to the calculation result, so as to on-line adjust the inclination of the pickup head.