Abstract: An optical device having an irradiated portion formed of an optical recording medium in which a pit is formed on a reflection surface, a semiconductor unit in which a semiconductor laser, a semiconductor structure and a photo-detection element are formed on the same semiconductor substrate, and a converging device for converging a light emitted from the semiconductor laser and irradiating the same of the irradiated portion and further converging a returned light reflected from the irradiated portion. The semiconductor structure is formed near the confocal of the converging device and includes at least three reflection surfaces. The photo-detection element includes a first detection element for receiving a returned light reflected on the second reflection surface and a second detection element for receiving the returned light reflected on the third reflection surface.

Abstract: To provide a thin optical head including a diffractive optical element 5 and refractive optical element 9 having an optical plane into which the optical axis of light 2 emitted from a light source 1 diagonally comes in the optical path between the light source 1 and an information recording medium 11 and constituted so that the change of diffraction angles of the diffracted light emitted from the diffractive optical element 5 due to the wavelength fluctuation of the emitted light 2 and the change of refraction angles of the refracted light emitted from the refractive optical element 9 are produced so as to be canceled.

Abstract: An optical pickup apparatus for recording and/or reproducing information on an optical information recording medium includes a light source emitting a light flux, a light-converging optical system to converge a light flux emitted from the light source, having a coupling optical system which changes a divergent angle of a light flux emitted from the light source and an objective lens optical system which converges a light flux emerging from the coupling optical system on an information recording surface of the optical information recording medium, and an optical detector for detecting reflected light or transmitted light coming from the information recording surface of the optical information recording medium.

Abstract: An optical pickup apparatus includes a light source for emitting a light flux; and a converging optical system having a first, second, and third divided surface, which are divided in the order named from the vicinity of an optical axis of the converging optical system, for converging the light flux emitted from the light source, wherein a beam spot passing through the first and third divided surfaces is formed onto a first optical information recording medium having a transparent substrate whose thickness is t1, and a beam spot passing through the first and second surfaces is formed onto a second optical information recording medium having a transparent substrate whose thickness is t2 that is more than t1. The optical pickup apparatus further includes an image sensor for receiving a light flux reflected from the first and/or second optical information recording medium.

Abstract: An optical pickup device with the capability to read data from and write data to different kinds of optical discs in different formats and a composite optical device used in the optical pickup device. An optical pickup device is made by combining two laser couplers LC1 and LC2 that are designed for optimum read/write specifications for optical discs which are different in format from each other. In one embodiment, two laser couplers LC1 and LC2 are incorporated on a common photodiode IC to form a single laser coupler, and the laser coupler is used in an optical pickup device.

Abstract: An optical pickup device comprises a semiconductor laser, an optical system which converges light projected by the semiconductor laser onto an optical disk and directs reflected light from the optical disk to a photoreceptor element, and a photoreceptor element which detects the reflected light; the photoreceptor element including at least two main photoreceptive domains divided from one another by a dividing line, which receive reflected light corresponding to a focusing error of the light projected onto the optical disk, and at least one auxiliary photoreceptive domain which detects reflected light which exceeds the main photoreceptive domains in a defocused state; in which the auxiliary photoreceptive domain is provided adjacent to an end of said main photoreceptive domains in the direction of the dividing line.

Abstract: A semiconductor device includes a photodetector having a junction at which a first conductive type first semiconductor portion and a second conductive type second semiconductor portion are joined to each other. In this photodetector, division regions are formed in part of the first semiconductor portion in such a manner as to cross the first semiconductor portion and partially enter the second semiconductor portion, so that the junction is divided into a plurality of parts by the division regions, to form a plurality of photodetector regions having the divided junction parts.

Abstract: A polarization-sensitive beam splitter comprising at least one transparent wedge-shaped element of a birefringent material is made by providing each one of two substrate plates with an orientation layer, whereafter the substrate plates are arranged with their orientation layers facing each other while forming a wedge-shaped interspace. The interspace is filled with a liquid crystalline monomer composition, which is subsequently cured while forming a wedge-shaped element of a uniaxially oriented polymer material. After possible removal of the substrate plates, two or three of such wedge-shaped elements can be joined to a Wollaston prism for use in the pick-up element of a magneto-optical recording system.

Abstract: A process for a master optical disk of the present invention is a process for a master optical disk having a physical format in which in a groove-and-prepits-included rewritable optical disk, prepits not being on spirals identical to those of a groove, for example, prepits shifted outward and inward by a half-track pitch from the groove center, are recorded, wherein an acoustooptic-effect-used optical deflector or a field-optical-effect-used optical deflector 101 is disposed on an optical path of a mastering apparatus so that a single laser beam is deflected. This process makes it possible to use a single processing scan to perform laser processing for a plurality of arbitrary points, for example, the center of the groove, and positions shifting inward and outward by a half-track pitch from the center.

Abstract: An integrated light emitting and receiving device capable of detection of the tracking condition and the focus condition by simple configuration and capable of reduction of the size of the semiconductor integrated circuit substrate on which the light receiving elements are formed, provided with a laser diode as a light emitting element formed on the substrate for outputting light in a predetermined direction, a prism as a light splitting means for outputting the light of the laser diode to the optical disc, focusing the reflected light onto a first photodetector, and focusing the light reflected at the first photodetector to a second photodetector by a predetermined optical path, a tracking condition means for detecting the tracking condition only from the information of the amount of the received light of the first photodetector, and a focus condition detecting means for detecting the focus condition only from the information of the amount of received light of the second photodetector.

Abstract: A light receiving element (7) receiving return light from an optical disk has main light receiving sections (7a, 7b) and sub light receiving sections (7e, 7f). A focus error signal is found by computing (Sa+Sf )−(Sb+Se), where Sa, Sb, Se, and Sf represent output signals of the light receiving sections (7a, 7b, 7e, 7f), respectively. Each of the sub light receiving sections (7e, 7f) has a smaller area than each of the main light receiving sections (7a, 7b) has. With the foregoing arrangement, upon access to a multilaminate optical disk in which distances between recording layers are small, respective focus error signals from the recording layers do not interfere with each other, and occurrence of an offset can be suppressed even in the case where an assembly error of the optical element or the like exists.

Abstract: An optical pickup device is provided with a focus error signal generating means which is adapted to calculate a first output sum signal obtained by adding together an output signal fed front one portion of the second light receiving means and an output signal fed from one portion of the third light receiving means, and to calculate a second output sum signal obtained by adding together an output signal fed from the other portion of the second light receiving leans and an output signal fed from the other portion of the third light receiving means, so as to calculate a difference between the first output sum signal and the second output sum signal, thereby producing a focus error signal.

Abstract: An integrated light emitting and receiving device capable of detection of the tracking condition and the focus condition by simple configuration and capable of reduction of the size of the semiconductor integrated circuit substrate on which the light receiving elements are formed, provided with a laser diode as a light emitting element formed on the substrate for outputting light in a predetermined direction, a prism as a light splitting means for outputting the light of the laser diode to the optical disc, focusing the reflected light onto a first photodetector, and focusing the light reflected at the first photodetector to a second photodetector by a predetermined optical path, a tracking condition means for detecting the tracking condition only from the information of the amount of the received light of the first photodetector, and a focus condition detecting means for detecting the focus condition only from the information of the amount of received light of the second photodetector.

Abstract: An optical read/write device for an information medium which includes a transparent substrate having an approximately plane face carrying at least one pair of electrodes defining an airgap area whose size corresponds approximately to the size of the information item to be written or to be read. The pair of electrodes constitute a resonator for an incident electromagnetic wave having one component of its electric field parallel to the direction of alignment of the electrodes of the pair of electrodes. An optical source illuminates the electrodes with an optical beam, one component of the electric field of which is parallel to the direction of alignment of the pair of electrodes. Under these conditions, when excited by the beam F1, the electrodes will re-emit a beam which has a field concentration within the airgap. The re-emitted beam makes it possible to read/write information on an information medium placed near the electrodes.

Abstract: A pad for controlling the state of contact or flying of a slider with or to an information-recording medium and a probe for exciting near-field light having a small spot size are mounted on the slider and the pad is near to the probe. Semiconductor laser light focused by an objective lens is converted into near-field light having a small spot size near the top of the probe for exciting near-field light. The slider travels at a height of several tens nm to a recording medium substrate and information is recorded or read out on or from the information-recording medium formed on the recording medium substrate.

Abstract: A diffraction grating having more than two kinds of mediums of a different refractive index, has a refractive index difference between the mediums dependent on an incident polarized light direction. In a sectional plane perpendicular to the direction along a grating pattern, the structure has a boundary line between the mediums periodic for the direction perpendicular to the grating pattern in a grating plane or periodic while enlarging or shrinking to the direction perpendicular to the direction along with the grating pattern in the grating plane and in a limited part of a period, the boundary line does not have a symmetrical plane perpendicular to both of the grating and the sectional plane. Accordingly, a polarized light beam status of ±nth order diffracted light beams becomes different and there is provided a diffraction grating capable of obtaining a generation signal of a magneto-optical recording medium from a difference of an optical amount of a light beam received.

Abstract: An optical pickup device has a single light beam path in which at least one or either of a plurality of kinds of light beams (different from each other in, for example, wavelength) for respective recording densities and/or recording-medium-thicknesses proceeds toward a surface of an optical recording medium and proceeds to a light beam detector after being reflected by the surface.

Abstract: An optical pickup device has a single light beam path for common use in treating or passing either of a plurality of kinds of light beams for respective recording densities and/or recording-medium-thicknesses different from each other, in other words, at least one or either of the plurality of kinds of light beams is introduced into the common single light beam path which may includes a single quarter-wave plate and/or single collimator and/or single objective.

Abstract: In manufacturing an optical pickup, an adhesive is applied between an optical waveguide device and a wedge-shaped device fixing member, and an adhesive is applied between the wedge-shaped device fixing member and a stem. After the position of the optical waveguide device is adjusted in three-dimensional directions of an optical axis direction and directions orthogonal to the optical axis by moving the wedge-shaped device fixing member, the optical waveguide device and the wedge-shaped device fixing member are fixed.

Abstract: An optical pickup apparatus includes a light source for emitting a light flux; and a converging optical system having a first, second, and third divided surface, which are divided in the order named from the vicinity of an optical axis of the converging optical system, for converging the light flux emitted from the light source, wherein a beam spot passing through the first and third divided surfaces is formed onto a first optical information recording medium having a transparent substrate whose thickness is t1, and a beam spot passing through the first and second surfaces is formed onto a second optical information recording medium having a transparent substrate whose thickness is t2 that is more than t1. The optical pickup apparatus further includes an image sensor for receiving a light flux reflected from the first and/or second optical information recording-medium.

Abstract: The present invention relates to an information reading and writing device for an optical signal, and the optical system is simplified by using a diffraction optical element. A semiconductor laser is used as a light source. There is provided an image formation lens for condensing a beam of light and forming an image on an optical disk medium. In an optical path between the semiconductor laser and the image formation lens, there is provided a hologram having a function of the hologram region diffraction optical element for detecting a tracking error signal of the medium and a focus detection error signal. Two optical detecting elements 24a, 24b for detecting the focus error respectively have two divided regions. Under the condition that the medium is in focus, beams of light diffracted in the two hologram regions 23a, 23b for detecting the focus become the convergent beams which are most converged on a dividing line of the respective optical detecting element and in the direction of the optical axis.

Abstract: A device for reading from and/or writing to optical recording media, including a beam generator, a focus device, which focuses the beam generated onto the optical recording medium at a focal point, a displacement device, which displaces the position of the focal point on the recording medium in accordance with a first direction of movement in dependence on an actuating signal, and a detector, which detects a beam reflected from the optical recording medium and outputs a regulating signal to a regulator. The regulator generates an actuating signal for the displacement device. The invention allows a higher data transfer rate to be achieved with an acceptable outlay. This is achieved by a beam influencing device arranged in the beam path and, in dependence on a further actuating signal of the regulator, influences the position of the focal point on the recording medium in accordance with the first direction of movement.

Abstract: Methods and apparatus are provided for retrieving encoded information from data tracks on an optical disk using an array of microlasers as the illumination sources, an array of micro-scale photo detectors as the detection elements, and a bilens (BL) as the main optical component. Multiple configurations are provided to position microlasers and photo detectors together on a mobile laser/detector block (LDB). Laser beams generated by the surface-emitting microlasers are guided by the BL onto the optical disk (OD) surface. The reflected light is collected by the same BL, shifted, and then directed back onto the respective photo detectors on the LDB. Illumination, detection and alignment methods and apparatus for tracking, focusing, and magnification servo controls are also incorporated on the LDB.

Abstract: A semiconductor laser device includes a semiconductor laser element for emitting laser light onto a recording medium; beam dividing element provided in an optical path between the semiconductor laser element and the recording medium; a hologram optical element including a diffraction grating formed in a light-transmitting substrate, the hologram optical element located in an optical path between the beam dividing element and the semiconductor laser element; a servo-signal light-receiving element provided in an optical path of diffracted light transmitted through the diffraction grating for receiving the diffracted light; an information-signal light-receiving element for receiving light divided by the beam-dividing element, which is different from light divided by the beam-dividing element which is received by the diffraction grating; and a polarizing element provided in an optical path between the beam dividing element and the information-signal light-receiving element, wherein the semiconductor laser element

Abstract: A semiconductor laser apparatus comprises a semiconductor substrate, a semiconductor laser which is fixed on the semiconductor substrate and a prism having a slanted plane. The prism is placed such that its slanted plane faces a side across from the semiconductor laser. The apparatus also includes an optical detector for monitoring which is formed on the surface of the semiconductor substrate. The surface is covered by the prism. The following are formed on the slanted plane of the prism: a reflection region on which the surface is processed for reflecting a part of an emitted light beam from the semiconductor laser and a transmissive refraction region on which the surface is processed such that the remaining part of the emitted light beam is transmitted and refracted to be guided to a light receiving plane of the optical detector for monitoring.

Abstract: An optical pickup apparatus which can be designed compact while having a plurality of semiconductor lasers. The optical pickup apparatus, which reads recorded information from an optical recording medium, comprises an optical system including light intensity detection element having a quarter-split light receiving surface, two semiconductor lasers for emitting light beams of different wavelengths, an objective lens for directing each of the light beams onto an optical recording medium to form a light spot on a recording surface, and a holographic optical element located between the quarter-split light receiving surface and the objective lens, whereby the holographic optical element eliminates coma aberration and spherical aberration of light beams launched from the two semiconductor lasers and traveled through the recording surface and the objective lens, thereby generating a predetermined amount of astigmatism.

Abstract: The optical pickup device includes a two wavelength semiconductor laser (23) selectively generating a laser beam having the wavelength of 635 nm and laser beam having the wavelength of 780 nm, a collimator lens (24), a hologram (25) formed on a surface of collimator lens (24), a polarizing glass (22) having an annular polarizing region (40) and an objective lens (21). Hologram (25) does not diffract the laser beam having the wavelength of 635 nm, and diffracts outward the laser beam having the wavelength of 780 nm. Therefore, virtual light source of the laser beam having the wavelength of 780 nm comes closer to the collimator lens (24) than the light source of the laser beam having the wavelength of 635 nm. Therefore, objective lens (21) focuses the laser beam having the wavelength of 635 nm on a recording surface of a transparent substrate (31) of a DVD, and focuses the laser beam having the wavelength of 780 nm on a recording surface of a transparent substrate (32) of a CD-R.

Abstract: An optical pickup device for condensing the light from a light source on a signal recording surface by an objective lens and for detecting the return light from the signal recording surface by a light detection unit is disclosed. The optical pickup device is capable of recording and/or reproducing at least two different sorts of optical recording media. The light beam radiated from a light source is condensed by an objective lens. An aperture varying unit varies the size of an aperture of the objective lens depending upon the sorts of the optical recording media. The return light from the optical recording medium is detected by a light detection unit. The size of the aperture of the objective lens for condensing the light from the light source is varied depending upon the difference in substrate thickness of the different sorts of the optical recording media, thus assuring high-quality recording/reproduction for two or more different sorts of optical recording media.