Patent ID: 8289825

Claim:
An optical disk drive, comprising: a seek control device, controlling a pickup head having a sled and a lens for projecting a beam on a disk, moving the sled, and shifting the lens with a shift distance relative to an origin at a center of the sled; an equalizer, deriving a servo signal from a reflection of the beam; a lens vision characteristic decoder, obtaining a vision characteristic of the lens according to the servo signal and generating a track-on direction signal according to the vision characteristic of the lens, the vision characteristic of the lens obtained responsive to receiving the servo signal derived from a first reflection corresponding to a first location on the disk and a second reflection corresponding to a second location on the disk; and an anti lens shift device, triggering the seek control device to perform a track-on process according to the track-on direction signal, wherein the anti lens shift device further determines a shift direction of the lens relative to the sled according to the servo signal after the track-on process is performed, and generates a force to move the sled according to the shift direction, allowing the lens to be located at a predetermined position after the track-on process is completed.