Abstract: An optical pickup apparatus includes an astigmatic element, an angle adjusting element for contradicting propagation directions of luminous fluxes within four different luminous flux regions out of a reflected light, a polarization adjusting element. Two of the luminous flux regions are placed in a direction in which aligned are a set of opposite angles made by the two mutually crossing straight lines respectively parallel to a first convergence direction and a second convergence direction vertical to the first convergence direction by the astigmatic element, and the remaining two luminous flux regions are placed in a direction in which an alternate set of opposite angles are aligned. The polarization adjusting element differentiates polarization directions of luminous fluxes which are selected out of the luminous fluxes within the four luminous flux regions and which are adjacent in a peripheral direction in which the optical axis of reflected light serves as an axis.

Abstract: In an optical disk apparatus, after chucking an optical disk, the optical disk apparatus defers the start of the rotation of the optical disk, and measures the focusing drive voltage at two points, i.e., a point near a center of the optical disk and a point near an outer edge of the optical disk. Then, based on the measured values, the optical disk apparatus determine the angle at which the optical disk is slanted. Therefore, when the optical disk has been chucked inappropriately, the chucking state can be determined without rotating the optical disk, and scratching of the optical disk and damage to the optical disk apparatus can be prevented.

Abstract: An optical disk apparatus has a first optical system having an objective lens with a first NA, a second optical system having an objective lens with a second NA lower than the first NA, an addition mechanism for adding focus error signals detected by the first and second optical systems, and an alignment mechanism for aligning the objective lens in accordance with the addition result of the addition mechanism.

Abstract: An exposure apparatus for an optical disc used for eliminating the vibrations in the propagating direction when a rotation mechanism rotates. The slider controller 40 and the spindle controller 41 of the exposure apparatus 1 are activated, and the then the optical disc begins to be rotated by an AC synchronized motor. Through a condensing device 9, laser beams emitted form the laser source 6 are irradiated on the optical disc for exposure. At this time, the optical disc is eccentrically chucked on the rotation mechanism, resulting a rotational vibration of the whole rotation mechanism. A measurer 17 is used for detecting a propagating component of the rotational vibration, and a vibrator controller 42 controls the vibrator 20 as the output of the measurer 17 approaches zero. Therefore, the vibration in the propagating direction of the base 2 is cancelled, and the propagation accuracy is increased and the exposure quality is enhanced.

Abstract: An optical pickup can be provided, the optical pickup being capable of recording and playback of a plurality of optical disks having different specs by using light beams of different wavelengths, and further being suitable for integrating the semiconductor lasers and light receiving elements into a single package, by including: first and second semiconductor lasers adjacently disposed; a three-beam diffraction grating for generating three beams for tracking control; a second hologram element for diffracting light of the second semiconductor laser to guide it to a photosensor; a complex polarization beam splitter (PBS) for reflecting only light from the first semiconductor laser; and a first hologram element for diffracting light of the first semiconductor laser to guide it to the photosensor.

Abstract: The present invention provides a method for guiding a pick-up head to follow an information track. The method comprises the steps of sensing and sending notification of displacement between the pick-up head and the center of the information track, generating a first correction directly proportional to the displacement, generating from the first correction a second correction non-proportional to the displacement, generating a third correction from an amplified tracking error signal and generating a driving force proportional to the sum of the second and third corrections, driving the pick-up head to follow the information track.

Abstract: An optical disk apparatus has a first optical system having an objective lens with a first NA, a second optical system having an objective lens with a second NA lower than the first NA. The optical disk apparatus at the time of processing the optical disk, when the optical system suitable recording/reproduction process of the optical disk is the second optical system, via the first optical system detecting a surface run-out of the optical disk and execute the focus lead-in process of the second optical system on the basis of a surface run-out detected; and when at the time of processing the optical disk, when the optical system suitable recording/reproduction process of the optical disk is the first optical system, processing the optical disk with the first optical system without detecting the surface run-out of the optical disk.