Patent ID: 9508379
Filing Date: 2016-11-29
CPC Classification: G11B

Claim Text:
1. A recording apparatus comprising: a light source configured to emit a light beam; an objective lens configured to focus the light beam on a recording medium having a groove-shaped track capable of recording information; a beam splitter configured to split the light beam reflected and diffracted by the recording medium from a light path of the light source; an optical element configured to divide the light beam split by the beam splitter into desired regions; a detector configured to receive a light of each region of the desired regions divided by the optical element; and a first operation circuit configured to calculate a signal received from the detector and output the signal, wherein the optical element divides the light beam split by the beam splitter, into a first main region mainly including a region in which a zero-order light and a plus first-order diffracted light of the track overlap with each other, a second main region mainly including a region in which the zero-order light and a minus first-order diffracted light of the track overlap with each other, a first main end region mainly including both ends in a track tangential direction of the region in which the zero-order light and the plus first-order diffracted light of the track overlap with each other, a second main end region mainly including both ends in the track tangential direction of the region in which the zero-order light and the minus first-order diffracted light of the track overlap with each other, a first sub-region located at both ends outside of the first main end region in the track tangential direction, and a second sub-region located at both ends outside of the second main end region in the track tangential direction, and the first operation circuit generates a first main signal in which a signal from the first main end region is multiplied by a coefficient α that is greater than 1 and added to a signal from the first main region, and a second main signal in which a signal from the second main end region is multiplied by the coefficient α and added to a signal from the second main region.