Matsushita Electric Industrial Co., Ltd.

Jouji Anzai

Hideki Hayashi

Sadao Mizuno

Hiroaki Yamamoto

Tomotada Kamei

Yoshiaki Komma

Hiroshi Yamamoto

Kousei Sano

Shin-ichi Kadowaki

Kanji Wakabayashi

Daisuke Ogata

Akihiro Yasuda

Hitoshi Fujii

Eishin Mori

Yasumasa Shibata

A lens support mechanism including a semiconductor laserfor emitting a laser beam, an optical head enclosureto which the semiconductor Laseris fixed and located, a collimator lensdisposed coaxially with the laser beam emitted from the semiconductor laser, a resin cylinderformed in a cylindrical shape so as to fix and locate the collimator lensto the inner surface thereof and a cylindrical memberfitted to the resin cylinderon a side of the collimator lensopposite to the semiconductor laserand formed so as to be fixed to the optical head enclosure. The cylindrical memberhas almost the same linear expansion coefficient as that of the optical head enclosure

Lens support mechanism, optical head device and optical information processor

An optical head reproduces optical disks of different disk plate thickness t(0.6 mm) or t(1.2 mm) by using light beams of two wavelengths and one object lens. An converging element comprises a central portion and outer portion, wherein the central portion has optimum design plate thickness of 0.6*tto tand the outer portion has optimum design plate thickness of 0.6 mm. By providing a step difference in the converging element, information can be recorded or reproduced for an information medium of disk plate thickness tand for an information medium of disk plate thickness t, in a state having small side lobes. Alternatively, a step difference is provided in the object lens, and optical distance Lfrom a second light source to a condensing optical system is set to 80 to 95% of optical distance Lfrom a first light source to the condensing optical system. Alternatively, only light of first wavelength is shielded or diffracted in a ring-like shape.

Converging element, optical head, and apparatus and method of optically recording and reproducing information

An optical head reproduces optical disks of different disk plate thickness thicknesses t1 (0.6 mm) or t2 (1.2 mm) by using light beams of two wavelengths and one object lens. An converging element comprises a central portion and outer portion, wherein the central portion has optimum design plate thickness of 0.6*t1 to t1 and the outer portion has optimum design plate thickness of 0.6 mm. By providing a step difference in the converging element, information can be recorded or reproduced for an information medium of disk plate thickness t1 and for an information medium of disk plate thickness t2, in a state having small side lobes. Alternatively, a step difference is provided in the object lens, and optical distance L2 from a second light source to a condensing optical system is set to 80 to 95% of optical distance L1 from a first light source to the condensing optical system. Alternatively, only light of first wavelength is shielded or diffracted in a ring-like shape.

An optical pickup head is provided with a light source, a diffracting means for creating a plurality of diffracted beams, a converging means for focusing the diffracted beams onto an optical storage medium, a beam branching means for branching the plurality of beams reflected by the optical storage medium, and an optical detecting means for outputting a signal corresponding to the amount of light of the received beams. The optical detecting means has main beam light receiving portions and sub-beam light receiving portions. The amount of light of the first or higher order diffracted beams when they are substantially focused on and reflected by a focus plane of the plurality of information recording planes is equal to or greater than the amount of light of the zero order diffracted beam when it is reflected without focusing by a non-focus plane other then the focus plane of the plurality of information recording planes. The invention provides an optical pickup head where offset is not generated in the TE signals even during tracking with the objective lens when a two-layered disk is used.

Optical pickup head and information recording/reproducing device

In a objective lens driver, at least one permanent magnet is mounted on a movable member, and plural yokes, each being wound with a coil having its winding axis in the focusing direction, are disposed facing the permanent magnet. The yokes are arranged almost symmetrically about a plane including the center of gravity of the movable member and being perpendicular to the tracking direction. In this structure, even when the movable member moves in the tracking direction, since the permanent magnet (a magnetic field source) also moves with the movable member, the distribution of magnetic flux density that contributes to the drive also shifts according to the movement of the movable member, so that the distribution of magnetic flux density maintains being almost symmetrical about the center of gravity of the movable member. Accordingly, in tilt drive, a constant sensitivity to tilt drive is obtained regardless of the position of the movable member. Further, since the rotation axis of tilt drive is fixed, there arises no crosstalk of displacement in the focusing direction and the tracking direction. Furthermore, since the point of action of driving force on the movable member is fixed, there arises no crosstalk of angular displacement in the tilt direction due to focusing drive and tracking drive. Consequently, stable focusing control, tracking control and tilt correction control are realized in an objective lens driver capable of correcting a tilt.

Objective lens driver

Growing community of inventors

Suita, Japan

Jouji Anzai