Patent ID: 6084835
Filing Date: 2000-07-04
Classification: G11B

Abstract:
A device for reading from or writing to optical recording media by means of a light beam, comprising:an objective lens for focusing the light beam on the recording medium;detector elements arranged laterally with regard to the direction of a track of the optical recording medium, for converting light reflected from the recording medium into electrical signals;a phase comparator responsive to phases of electrical signals emitted by the detector elements to provide a tracking signal proportional to phase differences exhibited by said electrical signalsan identification circuit which evaluates the signals emitted by the detector elements, for developing a signal related to axial alignment of the objective lens;signal combining circuitry, responsive to said signal related to axial alignment, and said tracking signal to produce a corrected tracking signal; anda driver, responsive to said corrected tracking signal, for causing said objective lens to follow a track on the recording medium.