Patent ID: 6885621
Filing Date: 2005-04-26
Classification: G11B

Abstract:
1. An error signal detection method for an optical recording/reproducing system, the method comprising: (a) detecting a light incident through an objective lens after having been reflected and diffracted from a recording medium, as eight light portions arranged in a 2×4 matrix, including four inner light portions, and four outer light portions around corresponding inner light portions, wherein a row and a column of the matrix are parallel to a tangential and a radial direction of the recording medium, respectively; (b) calculating a first sum signal by summing a detection signal from one of the outer light portions located in a first diagonal direction, and a detection signal from one of the inner light portions located in a second diagonal direction; (c) calculating a second sum signal by summing a detection signal from one of the inner light portions located in the first diagonal direction, and a detection signal from one of the outer light portions located in the second diagonal direction; (d) comparing phases of the first and second sum signals and outputting a phase comparison signal, and detecting a tilt error signal from the phase comparison signal.