Device for reducing cross talk in signal detecting apparatus used in an optical pickup device

A tracking error signal detecting apparatus that detects a tracking error signal from light reflected/deflected from a recording medium having radial and tangential directions, comprising:

• a photodetector to receive the light reflected/diffracted from the recording medium and produce detection signals, said photodetector comprising
• four light receiving regions arrayed counterclockwise that are divided by first dividing lines that are substantially parallel to the radial and tangential directions of the recording medium,
• each of the four light receiving regions comprises
• an inner sectional plate, and
• an outer sectional plate,
• wherein the inner and outer sectional plates are bisected by second dividing lines such that respective radial widths vary along ± tangential directions from a center of said photodetector,
• wherein the eight inner and outer sectional plates are arrayed in a 2×4 matrix such that the directions of columns and rows of the sectional plates correspond to the radial and tangential directions of the recording medium;
• and
• a circuit unit to
• amplify at least some of the detection signals of the inner and/or outer sectional plates positioned in one diagonal direction with a predetermined gain,
• compare phase differences between the amplified signals and at least some of the detection signals of the inner and/or outer sectional plates positioned in the other diagonal direction to produce a phase difference signal, and
• detect the tracking error signal from the phase difference signal.

A reproduction signal detecting apparatus that detects a tracking error signal from light reflected/deflected from a recording medium having radial and tangential directions, comprising:

• a photodetector that receives the light reflected/diffracted from the recording medium and produces detection signals, said photodetector comprises
• four light receiving regions arrayed counterclockwise that are divided by first dividing lines that are substantially parallel to the radial and tangential directions of the recording medium,
• each of the four light receiving regions comprise
• an inner sectional plate, and
• an outer sectional plate,
• wherein the inner and outer sectional plates are bisected by second dividing lines such that respective radial widths vary along ± tangential directions from a center of said photodetector,
• wherein the eight inner and outer sectional plates are arrayed in a 2×4 matrix with the directions of columns and rows of the sectional plates corresponding to the radial and tangential directions of the recording medium;
• and
• a circuit unit that comprises:
• an amplifier that amplifies a sum signal of the detection signals of the outer sectional plates, and
• an adder that adds a sum signal of the detection signals of the inner sectional plates and the output signal of the amplifier to produce the reproduction signal.