Hitachi Media Electronics Co., Ltd.

Hitachi, Ltd.

Yasuo Kitada

Toshimasa Kamisada

Yoshiro Konishi

Tomoto Kawamura

Kazuyoshi Yamazaki

Masayuki Inoue

Tohru Sasaki

Kunikazu Ohnishi

Akira Saito

Hiromitsu Mori

Toshiyasu Hattori

Susumu Tachibana

Kunikazu Oonishi

An optical pickup device includes a semiconductor laser for emitting laser light, an objective lens for irradiating luminous flux emitted from the semiconductor laser to an optical disc, a branching element having a plurality of regions for branching luminous flux reflected from the optical disc to a plurality of fluxes, and a photodetector having a plurality of light receiving parts which receive luminous flux branched by said branching element. Luminous flux which enters at least two regions arrayed along a direction which is made substantially coincident with a tangential direction of the optical disc in regard to substantially a center of the branching element is arranged along a direction which is made substantially coincident with a radial direction of the optical disc on the photodetector.

Optical pickup device and optical disc apparatus

An optical pickup includes a first source which emits a first beam with a first wavelength; a second source which emits a second beam with a wavelength shorter than the first wavelength; a first collimate lens which collimates the first beam; a second collimate lens which collimates the second beam; a first objective lens which converges the first collimated beam onto an optical disc; and a second objective lens which converges the second collimated beam onto the disc. The first and second objective lenses are arranged in the disc radial direction. The second objective lens is arranged closer to the side of the disc outer circumference than the first objective lens. The first collimate lens is arranged on the right-hand side when the second objective lens is viewed from the first objective lens. The second collimate lens is arranged on the left-hand side when the first objective lens is viewed from the second objective lens. The gap between the first collimate lens and the first objective lens is larger than the gap between the second collimate lens and the second objective lens.

Optical pickup having radially arranged lenses in a low profile construction

An optical pickup equipped with a laser light source which emits light beams of at least three wavelengths for recording/reproducing a plurality of information recording media detects light quantities of the light beams of three wavelengths using one light intensity monitor element. More specifically, one light intensity monitor element is arranged between a first laser light source and a second laser light source, light beams of wavelength &#x3bb;and wavelength &#x3bb;emitted from the first laser light source are made to proceed substantially straightforward, the optical path of the light beam of wavelength &#x3bb;emitted from the second laser light source is changed to a diagonal one so as to cause the light beam to be introduced diagonally to the light receiving surface of the one light intensity monitor element. Furthermore, the central axis line of the light receiving surface of the one light intensity monitor element is separated from the emitted light axis of the first laser light source and a reflecting member is provided above the emitting light axis of the second laser light source.

Optical pickup and optical information recording and reproducing device

In the optical pickup device, while reflection light reflected from the optical multi-layer disc is divided into a plurality of regions so as to produce a plurality of divided optical beams, the divided optical beams are focused onto different positions on a photodetector, and a focus error signal is detected by employing a plurality of the divided optical beams by utilizing the knife edge method, and further, a tracking error signal is detected by employing a plurality of the divided optical beams. Furthermore, the dividing regions of the optical beam and light receiving parts are arranged in such a manner that stray light derived from other layers of the optical disc is not entered to a servo signal-purpose light receiving part of the photodetector when the divided optical beam is focused onto a target layer of the optical disc.

An optical pickup apparatus is provided with a dividing element having a plurality of regions. The dividing element is capable of dividing a light flux reflected by the optical disc into a plurality of light fluxes having different outgoing directions. Each region of the dividing element and light receiving parts of a light detector are structured such that when a target information recording layer of the optical disc is brought into focus, a light flux reflected from the target information recording layer is focused on the light receiving parts of the light detector, and a light flux reflected from other information recording layer than the target information recording layer is not irradiated onto the light receiving parts of the light detector.

Optical pickup apparatus and optical disc apparatus with a single beam system

An optical pickup apparatus includes a semiconductor laser for emitting a laser light, an objective lens for irradiating the light flux emitted from the semiconductor laser onto an optical disc, and a light detector for receiving the light flux reflected from the optical disc. The light detector has a light receiving part that comprises five regions of a region, a region, a region, a regionand a region

Optical pick up apparatus with a single beam system and having a diffraction grating

An optical pickup apparatus includes a semiconductor laser for emitting a laser light, an objective lens for irradiating the light flux emitted from the semiconductor laser onto an optical disc, and a light detector for receiving the light flux reflected from the optical disc. The light detector has a light receiving part that comprises a region, a region, a region, a region, a region, a regionand a region

An optical pickup includes a first source which emits a first beam with a first wavelength; a second source which emits a second beam with a wavelength shorter than the first wavelength; a first collimates lens which collimates the first beam; a second collimate lens which collimates the second beam; a first objective lens which converges the first collimated beam onto an optical disc; and a second objective lens which converges the second collimated beam onto the disc. The first and second objective lenses are arranged in the disc radial direction. The second objective lens is arranged closer to the side of the disc outer circumference than the first objective lens. The first collimate lens is arranged on the right-hand side when the second objective lens is viewed from the first objective lens. The second collimate lens is arranged on the left-hand side when the first objective lens is viewed from the second objective lens. The gap between the first collimate lens and the first objective lens is larger than the gap between the second collimate lens and the second objective lens.

Optical pickup apparatus and optical disc apparatus using same

An optical disk apparatus includes a motor to rotate an optical disk and an optical head to apply light to the optical disk. The optical head includes a light source to emit the light to be applied to the optical disk, and a collimating lens to receive and collimate the light emitted by the light source. The collimating lens has an optical axis. The optical head also includes a support wall to support the collimating lens at a particular position. The support wall is configured to provide a gap between the collimating lens and the support wall to enable the collimating lens to be adjusted from an initial position to the particular position. The adjustment involves at least a movement in a direction that is perpendicular to the optical axis of the collimating lens. The optical head further includes an objective lens that is configured to receive the light from the collimating lens in order to apply the light to the optical disk.

Optical head and its adjusting method and optical disk device using the same

A multi-beam split-type optical head has optics including a stationary section and a movable section. A plurality of light beams generated from a plurality of light sources in the stationary section are parallel to a shifting direction of the movable section until entering the movable section, are then overlapped by a mirror or a dichroic mirror in the movable section such that they are mutually inclined with an angle .theta. therebetween, and converge at a plurality of positions each spaced by a predetermined distance on a track of an optical disk. The reflected light beams from the optical disk return to a detection optical system through the reverse itinerary.

Multi-beam split-type optical head for use in optical disk apparatus

A 2-laser optical head in which the number of optical parts is small and an arrangement is also simple and a whole optical system can be miniaturized. As a construction to realize the 2-laser optical head, there is a construction in a 2-laser optical head comprising at least: semiconductor laser devices for rewriting and reproducing; a beam splitter for transmitting a laser beam emitted from the reproducing semiconductor laser device and for reflecting a laser beam emitted from the rewriting semiconductor laser device; an objective lens for converging the laser beams and irradiating onto a recording surface of a magneto-optic disk, thereby forming a spot for reproduction and a spot for rewriting; a detection optical system for detecting a reflected light from the recording surface of the spot; and a detection optical system for detecting a reflected light from the recording surface of the spot, wherein a dichroism beam splitter is arranged in a manner such that the angles between normal vectors of incident surfaces and incident optical axes and are equal to 45.degree., and the occurrence of a phase difference which causes a deterioration of a deflecting state is corrected by a beam splitter.

2-laser optical head and recording/reproducing apparatus

There is disclosed an optical head device in which at least two laser beams having different wavelengths are converged as light spots on a recording medium or optical disk by use of one objective lens and one of the two laser beams is subjected to a focusing control while the recording or reproduction of a signal on or from the optical disk is made using the other laser beam. When the one laser beam is subjected to the focusing control, the deviation of a converging position of the other laser beam for the optical disk may occur due to a difference in refractive index between transparent substrates of plural kinds of optical disks. In such a case, the converging position of the other laser beam is displaced to cancel the amount of deviation.

Optical head device for recording/reproduction for recording medium

A magnetic clamp for a disk medium comprises a disk medium table for holding a disk medium, a spindle which supports the disk medium table rotatably, a hollow-cylindrical inner magnetic core and ring-shaped outer magnetic core each disposed inside the disk medium table concentrically with the spindle, a linkage magnetic core for connecting the inner and outer cores, and a permanent magnet inserted in any of the cores. The three cores form a magnetic circuit so that the magnetic flux passing through the magnetic circuit has a direction which is virtually coincident with the direction of magnetization of the permanent magnet.

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Odawara, Japan

Yasuo Kitada