ERROR SIGNAL DETECTING DEVICE FOR OPTICAL RECORDING AND PLAYING EQUIPMENT

摘要

PURPOSE: An error signal detecting device for optical recording and playing equipment is provided to consider phase features for areas of reflected and diffracted light beam, so as to correctly detect tangential tilt/radial tilt/defocus error signals without being affected by radial tilt, defocus and detrack/tangential tilt, defocus and detrack/tangential tilt, radial tilt and detrack, respectively. CONSTITUTION: An optical detector(30), as an optical detection unit, divides and detects light beam reflected/diffracted in an information stream of a recording medium and passing an objective lens into a first to a fourth light areas(A,B,C,D) in a direction corresponding to a radial direction of the recording medium, to output a first, a second, a fourth and a third detection signals(S11,S12,S14,S13). A circuit(50) sums a phase difference between the first and second detection signals and a phase difference between the third and fourth detection signals, for outputting. In the circuit, a first phase comparer(51) to which the first and second detection signals are inputted compares the phases thereof. A second phase comparer(53) to which the third and fourth detection signals are inputted compares the phases thereof. And a matrix circuit(55) operates signals inputted from the first and second phase comparers, for outputting.