Abstract: A method for performing a servo defect compensating operation by compensating a servo-related signal in an optical disc drive and a related optical disc drive system with a DSP is provided. The method comprises: reading an optical medium by an optical pick-up unit; detecting whether a defect exists by monitoring a side beam signal; when the defect on the optical medium is detected, determining a new compensation value based on a servo error signal; and compensating the servo-related signal with the new compensation value during defect crossing to adjust servo control when the optical pick-up unit passes the defect.

Abstract: A method is used for detecting a tilt of an optical pickup head. The method includes the steps of: capturing a plurality of images; converting the images to bitmap images; superposing the bitmap images together to form an superimposed bitmap image; setting a two-dimensional coordinating system of the superimposed bitmap image; determining coordinates of a first static spot, a second static spot, and dynamic spot; calculating a first distance between the first static spot and the dynamic spot, and a second distance between the second static spot and the dynamic spot based on the coordinates to determine a maximum distance; and comparing the maximum distance with a first standard distance to attain a conclusion whether the tilt is in an acceptable range.

Abstract: The optical disk recording/reproduction device is provided with an information recording area search means, comprising, a moving means which detects the presence and absence of information and return moves an optical pickup from inward to outward or from outward to inward direction of an optical disk, and a stopping means which stops the movement of optical pickup if an information recording area is detected in the movement of optical pickup. If the existence of information cannot be confirmed at a re-zeroing position in the initial operation, the optical pickup is moved to the inward of optical disk at a normal velocity; when the optical pickup passes through the information recording area, it is braked and stopped. If the existence of information can be confirmed at the stop position, the flow is shifted to normal reproduction; if it cannot be confirmed, the optical pickup is determined to pass through the information recording area and stop, returned from the stop position and moved outward at a low speed.

Abstract: In an optical head for performing the reproduction or recording of information for two or more types of different optical disks, the damage caused to an optical disk or an objective lens by collision between the optical disk and the objective lens is avoided. An optical heads device for reproducing or recording two or more types of information recording mediums different from each other comprises a first optical system, a second optical system, and a control unit for avoiding the collision between an optical disk and a second objective lens when a first optical system is in operation.