Patent ID: 6920010
Filing Date: 2005-07-19
Classification: G11B

Abstract:
1. A magnetic recording apparatus comprising: a disk-shaped information recording medium on which periodic physical changes providing changes of reflectivity are formed; a light source operable to output a light beam; a diffraction element operable to generate three light beams from the light beam outputted by the light source; a light-converging optical system operable to converge the three light beams generated by the diffraction element on the disk-shaped information recording medium as a microspot; a photodetection means having three photosensitive parts operable to receive light beams reflected and diffracted by the disk-shaped information recording medium and transmitted through the light-converging optical system, and output signals in accordance with quantities of the received light beams, respectively; a signal processing means for processing the signals outputted from the photodetection means to output a tracking error signal, the signal processing means including a cancel means for canceling crosstalk that occurs between the signals outputted from the three photosensitive parts of the photodetection means; a driving means for receiving the tracking, error signal outputted from the signal processing means, and determining a position of the light beam on a desired track of the disk-shaped information recording medium; and a magnetic head operable to record information on the disk-shaped information recording medium, or reproduce or delete information from the disk-shaped information recording medium, wherein the cancel means comprises: first and second voltage-dividing means for performing voltage division on the signal output respectively from a first photosensitive part of the three photosensitive parts of the photodetection means; a first differential arithmetic means for performing differential calculation on the signal output respectively from a second photosensitive part of the three photosensitive parts of the photodetection means and an output signal from the first voltage-dividing means; and a second differential arithmetic means for performing differential calculation on the signal output respectively from a third photosensitive part of the three photosensitive parts of the photodetection means and an output signal from the second voltage-dividing means.