Optical recording medium drive device, tracking error detection method

摘要

As for a quadruple light receiving unit, in a case where divided regions of A to D as in a DPD scheme is defined, when binarization signals of light reception signals in regions A to D are set as signals A to D, <1> exclusive OR between the signal A without delay and the signal B with delay, <2> exclusive OR between the signal A with delay and the signal C without delay, <3> exclusive OR between the signal B without delay and the signal D with delay, and exclusive OR between the signal B with delay and the signal D without delay are calculated, and a tracking error signal is obtained on the basis of the calculation of (<1>+<3>)−(<2>+<4>). Thus, the above problem can be solved.

主权项

1. An optical recording medium drive device comprising:
a light irradiation unit that performs light irradiation on an optical recording medium; a light receiving unit that receives reflected light from the optical recording medium and in which four regions of a first region, a second region, a third region and a fourth region are dividedly formed with a linear direction division line that extends in a direction corresponding to a longitudinal direction of a track formed in the optical recording medium and a tracking direction division line that extends in a direction corresponding to a short-side direction of the track, the first region and second region and the third region and fourth region being respectively segmented with the linear direction division line, the first region and fourth region and the second region and third region being respectively segmented with the tracking direction division line, the first region and second region and the third region and fourth region being arranged on an upstream side and a downstream side, respectively, on the basis of a direction of advancement of the track as a reference; a binarization unit that obtains binarization signals based on light reception signals which are obtained by the regions for light reception in the light receiving unit as a first signal, a second signal, a third signal and a fourth signal, respectively; delay units that delay the first signal, the second signal, the third signal and the fourth signal, respectively; a first exclusive OR calculation unit that calculates exclusive OR between the first signal inputted not via the delay unit and the third signal inputted via the delay unit; a second exclusive OR calculation unit that calculates exclusive OR between the first signal inputted via the delay unit and the third signal inputted not via the delay unit; a third exclusive OR calculation unit that calculates exclusive OR between the second signal inputted not via the delay unit and the fourth signal inputted via the delay unit; a fourth exclusive OR calculation unit that calculates exclusive OR between the second signal inputted via the delay unit and the fourth signal inputted not via the delay unit; and a first operation unit that calculates a difference between a sum of the pieces of exclusive OR calculated by the first and third exclusive OR calculation units, respectively, and a sum of the pieces of exclusive OR calculated by the second and fourth exclusive OR calculation units, respectively, wherein the first to fourth exclusive OR calculation units and the first operation unit operate asynchronous to channel clock.