Error signal detection apparatus and reproduction signal detection apparatus for optical recording/reproducing system and method therefor

An error signal detection apparatus for an optical recording/reproducing system, comprising;

• a photodetector which detects an information signal by receiving light reflected and diffracted from a recording medium, the photodetector comprising eight light receiving portions in a 2 row×4 column matrix, each light receiving portion to separately perform photoelectric conversion on light reflected and diffracted from the recording medium to generate a respective detection signal, the row of the matrix being parallel to a direction corresponding to a radial direction of the recording medium, the column of the matrix being parallel to a direction corresponding to a tangential direction of the recording medium, the eight light receiving portions including four inner light receiving portions arranged at the center region of the photodetector and four outer light receiving portions arranged around corresponding inner light receiving portions, a direction of an information stream recorded on the recording medium being defined as the tangential direction, and a direction perpendicular to the information stream being defined as the radial direction;
• and
• a circuit unit comprising:
• at least one amplifier which amplifies the detection signals generated by the inner and/or outer light receiving portions arranged in a first diagonal direction by a predetermined gain factor to output respective amplified signals, and
• a comparator which compares a phase of the amplified signal with a phase of the detection signals generated by inner light receiving portions and/or the outer light receiving portions arranged in a second diagonal direction, to output at least one of a tilt error signal and a tracking error signal based on the phase comparison.

An error signal detection apparatus for an optical recording/reproducing system, comprising:

• a photodetector which receives light reflected and diffracted from a recording medium, the photodetector comprising first through fourth light receiving portions arranged counterclockwise in order in a 2 row×2 column matrix and separated by a predetermined distance in a direction corresponding to the radial direction, each first through fourth light receiving portion to separately perform photoelectric conversion on light reflected and diffracted from the recording to generate a respective detection signal, the row of the matrix being parallel to the direction corresponding to a radial direction of the recording medium, and the column of the matrix is parallel to a direction corresponding to a tangential direction of the recording medium, a direction of information stream recorded in the recording medium is defined as a tangential direction, and a direction perpendicular to the information stream is defined as a radial direction;
• and
• a detection circuit unit, comprising:
• first and second delays which delay the phases of the respective detection signals generated by the first and second light receiving portions arranged in one row of the matrix, respectively;
• and
• a phase comparator which compares a phase of a sum of the delayed detection signal of the first light receiving portion and the detection signal generated by the diagonally opposite third light receiving portion, and a phase of a sum of the delayed detection signal of the second light receiving portion and the detection signal generated by the diagonally opposite fourth light receiving portion.

An error signal detection apparatus for an optical recording/reproducing system, comprising:

• a photodetector for receiving which detects light reflected and diffracted from a recording medium, the photodetector comprising first through fourth light receiving portions arranged counterclockwise in order in a 2×2 matrix, and separated in the radial and/or tangential direction, to separately perform photoelectric conversion on light reflected and diffracted from the recording medium, the first through fourth light receiving portions, wherein the row of the matrix is parallel to a direction corresponding to the radial direction of the recording medium, and the column of the matrix is parallel to a direction corresponding to the tangential direction, a direction of an information stream recorded on the recording medium being defined as the tangential direction, and a direction perpendicular to the information stream is defined as the radial direction;
• and
• a circuit unit comprising:
• an amplifier which amplifies a sum of the detection signals generated by the first and third light receiving portions arranged in a first diagonal direction by a predetermined gain factor;
• and
• a phase comparator which compares a phase of an output signal of the amplifier and a phase of a sum of the detection signals generated by the second and fourth light receiving portions arranged in a second diagonal direction, to detect at least one of a tilt error signal and a tracking error signal.

An apparatus for detecting a reproduction signal with a photodetector having eight light receiving portions in a 2×4 matrix, four inner light receiving portions arranged at the center region of the photodetector, and four outer light receiving portions arranged around the corresponding inner light receiving portions, wherein, when the direction of information stream recorded on the recording medium is defined as a tangential direction, and the direction perpendicular to the information stream is defined as a radial direction, the row of the matrix is parallel to a direction corresponding to the radial direction of the recording medium, and the column of the matrix is parallel to a direction corresponding to the tangential direction, the apparatus comprising:

• first through fourth delays which delay a predetermined period of time the detection signals generated by the inner and outer light receiving portions, respectively, arranged in one row;
• a first adder for summing a delayed detection signal for one of the inner light receiving portions arranged in a first diagonal direction and the detection signal generated by the other inner light receiving portion arranged in the first diagonal direction, to output a first sum signal;
• a second adder for summing a delayed detection signal for one of the outer light receiving portions arranged in the first diagonal direction and the detection signal generated by the other outer light receiving portion arranged in the first diagonal direction, to output a second sum signal;
• a third adder for summing a delayed detection signal for one of the inner light receiving portions arranged in a second diagonal direction and the detection signal generated by the other inner light receiving portion arranged in the second diagonal direction, to output a third sum signal;
• a fourth adder for summing a delayed detection signal for one of the outer light receiving portions arranged in the second diagonal direction and the detection signal generated by the other outer light receiving portion arranged in the second diagonal direction, to output a fourth sum signal;
• and
• a fifth adder for summing the first through fourth sum signals to output the reproduction signal.

A method of detecting an error signal in an optical recording/reproducing system, the optical recording/reproduction system adapted to reproduce an information stream from a recording medium having a tangential direction parallel to a direction of the information stream, the method comprising:

• providing a plurality of detectors which detect light reflected and diffracted from the recording medium, the detectors arranged in a matrix wherein at least two of the plurality of detectors are in each row and column of the matrix and the row of the matrix is parallel to the tangential direction of the information stream, each detector providing a respective detection signal having a phase relationship with respect to each of the other detectors;
• comparing the phases of at least two of the detection signals, other than signals provided from the same column;
• and
• generating an error signal based on the comparison;
• and
• generating at least one of an envelope signal and a center value signal from the error signal.

A method of detecting an error signal in an optical recording/reproducing system, the optical recording/reproduction system adapted to reproduce an information stream from a recording medium having a tangential direction parallel to a direction of the information stream, the method comprising:

• providing a plurality of detectors which detect light reflected and diffracted from the recording medium, the detectors arranged in a matrix wherein at least two of said plurality of detectors are in each row and column of the matrix and the row of the matrix is parallel to the tangential direction of the information stream, each detector providing a respective detection signal having a phase relationship with respect to each of the other detectors;
• summing at least four of the detection signals in pairs, other than a pair provided from the same column of the matrix;
• multiplying at least one of the summed signals by a predetermined factor;
• comparing a phase of at least one multiplied signal with a phase of at least one summed signal;
• and
• generating at least one of a tilt error signal and a tracking error signal based on the comparison.