Optical pickup and disk drive apparatus

An optical pickup, which is capable of recording or reproducing an information signal for a plurality of different types of disk-like recording media in which different wavelengths are used, for irradiating a laser beam, which has a wavelength corresponding to one of the plurality of different types of disk-like recording media and is emitted from a photoemission element, onto a disk-like recording medium through an objective lens, the optical pickup comprising:

• a diffraction elements including a first region for splitting the laser beams having different wavelengths into a main beam and a pair of first sub-beams, and a second region for splitting the laser beams into a main beam and a pair of second sub-beams,
• wherein, for a disk-like recording medium with any one of the plurality of different types, a following relation hold or approximately hold:
• (2n−1)×P/2
• where D is a distance between a spot center of the first sub-beam and a spot center of the second sub-beam, the spots being formed on a recording surface of the disk-like recording medium with being spaced in a substantially radial direction of the disk-like recording medium, n is a natural number, and P is a track pitch of the disk-like recording medium.

A disk drive apparatus comprising:

• a disk table on which a disk-like recording medium is mounted and rotated;
• and
• an optical pickup, in which an objective lens driving unit is supported on a moving base that moves in a radial direction of the disk-like recording medium mounted on the disk table, for irradiating a laser beam on the disk-like recording medium through an objective lens;
• wherein the optical pickup includes:
• a diffraction element including a first region for splitting the laser beam emitted from the photoemission element into a main beam and a pair of first sub-beams;
• and a second region for splitting the laser beam into a main beam and a pair of second sub-beams;
• wherein a following relation hold or approximately hold:
• (2n−1)×P/2
• where D is a distance between a spot center of the first sub-beam and a spot center of the second sub-beam, the spots being formed on a recording surface of the disk-like recording medium spaced in a substantially radial direction of the disk-like recording medium, n is a natural number, and P is a track pitch of the disk-like recording medium.

A disk drive apparatus capable of recording or reproducing an information signal for a plurality of different types of disk-like recording media in which different wavelengths are used, the disk drive apparatus comprising:

• a disk table on which a disk-like recording medium is mounted and rotated;
• and
• an optical pickup, in which an objective lens driving unit is supported on a moving base that moves in a radial direction of the disk-like recording medium mounted on the disk table, for irradiating a laser beam on the disk-like recording medium through an objective lens, the laser beam having a wavelength corresponding to the type of the mounted disk-like recording medium;
• wherein the optical pickup includes:
• a diffraction elements including a first region for splitting the laser beams having different wavelengths into a main beam and a pair of first sub-beams;
• and a second region for splitting the laser beams into a main beam and a pair of second sub-beams,
• wherein, for a disk-like recording medium with any one of the plurality of different types, a following relation hold or approximately hold:
• (2n−1)×P/2
• where D is a distance between a spot center of the first sub-beam and a spot center of the second sub-beam, the spots being formed on a recording surface of the disk-like recording medium with being spaced in a substantially radial direction of the disk-like recording medium, n is a natural number, and P is a track pitch of the disk-like recording medium.