Patent ID: 7057994

Claim:
An apparatus for reproducing information in an optical disk of a first recording density and in another optical disk of a second recording density lower than the first recording density, said apparatus comprising: an optical head having a light source operable to emit a main beam and sub-beams onto adjacent tracks formed in an optical disk, the main beam having a same spot size for the optical disk of the first recording density and the optical disk of the second recording density; a photodetector operable to detect reflection lights of the main beam and the sub-beams emitted by said light source from the optical disk; a reproduction device operable to reproduce information in the optical disk based on signals received from said photodetector; and a tracking controller operable to control tracking of said optical head having said light source based on output signals of said photodetector, wherein said light source emits the main beam to have a size in correspondence to a resolution of the optical disk of the first recording density in a direction tangent to the tracks and a shape longer in a direction perpendicular to the tracks, wherein said reproduction device has a first canceler operable to cancel cross talk components from adjacent tracks included in signals reproduced from reflection light of the main beam by using signals reproduced from reflection light of the sub-beams, and wherein said tracking controller comprises a tracking error signal generator operable to generate a tracking error signal based on a phase difference between signals of the reflection light of the main beam divided into a plurality of portions detected by said photodetector when information in the optical disk of the first recording density is reproduced, and operable to generate the tracking error signal based on signals of the reflection light of the sub-beams detected by said photodetector when information in the optical disk of the second recording density is reproduced.