Patent ID: 7440364

Claim:
A tracking error signal generating apparatus for generating a tracking error signal for tracking control which allows a light beam to follow a track on a recording surface of a recording medium, said tracking error signal generating apparatus comprising: a detecting device, which has four light receiving units divided by a first dividing line extending in a direction corresponding to a direction of crossing the track and a second dividing line extending in a direction corresponding to a direction along the track, for receiving reflected light of the light beam from the recording surface with the four light receiving units and for outputting detection signals corresponding to the reflected light received by the respective light receiving units; an adding device for adding the detection signals outputted from a first light receiving unit and a second light receiving unit, located on one side of a boundary made by the first dividing line, out of the four light receiving units and for outputting a result of the addition as an added signal; a first phase comparing device for outputting a first phase difference signal which indicates a phase difference between the detection signal outputted from the first light receiving unit and the added signal; a second phase comparing device for outputting a second phase difference signal which indicates a phase difference between the detection signal outputted from the second light receiving unit and the added signal; and a subtracting device for subtracting the second phase difference signal from the first phase difference signal.