Patent ID: 7499382

Claim:
A method for production of a lens position signal in a scanning unit for optical recording media having data recorded in tracks, with the scanning unit having an objective lens, which can assume different positions relative to the scanning unit, and a tracking control loop, producing an optical main beam and at least one secondary beam, with the main and secondary beams being focused on the recording medium, with the light that is reflected from the recording medium being evaluated by means of two or more photodetector which are associated with the beams, with a first error signal being derived from the signals of the photodetector segments which are associated with the main beam, and with a second error signal being derived from the signals of the photodetector segments which are associated with the secondary beams, and with the lens position signal being formed in the method by combination of the first error signal multiplied by a first branch weight (1+G) and the second error signal multiplied by a second branch weight (1−G, G); comprising: scanning of the optical recording medium in a way that a position of the beams on the recording medium varies relative to the track, measuring a first measurement signal, which contains in a first proportion a first signal component depending on the position of the objective lens relative to the scanning unit and a second signal component depending on the position of the scanning beam relative to the tracks on the recording medium, measuring a second measurement signal, which contains the first signal component and the second signal component in a second proportion different from the first proportion, evaluation of the measurement signals, adjustment of the branch weights (G, 1+G, 1−G) controlled by the result of the evaluation.