Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Mitsubishi Denki K.k.

Michihiro Tadokoro

Kazuo Okada

Hitoshi Imai

Satoshi Yasuda

Hitoshi Teramoto

Nobuo Takeshita

Masatoshi Takeda

Kimiyuki Koyanagi

Toshiya Matozaki

Teruo Fujita

Mitsuo Maeda

Motomu Yoshimura

Masatomo Seya

Ryuichiro Arai

An inverter apparatus converts a DC power of a capacitor charged via a rectifier circuit connected to a first AC power system into an AC power, and supplies the AC power to a second AC power system. The inverter apparatus includes a discharge circuit, a control circuit, a trigger circuit, a first voltage-sag detection circuit, a control power circuit, and a second voltage-sag detection circuit. When the second voltage-sag detection circuit detects a voltage sag of the control power circuit below a threshold, the trigger circuit generates a discharge command signal for causing the discharge circuit to discharge a charge from the capacitor.

Inverter apparatus with control and voltage-sag circuitry to quickly restart when recovering from a mini power failure

A SVC control section detects a bus voltage from an instrument transformer, and adjusts reactive power generated by a SVC according to the detected bus voltage. A cooperative control section generates a control command for controlling the interconnection and parallel-off of a phase lead capacitor and a phase lag reactor on the basis of the amount of reactive power generated by the SVC and the bus voltage detected by the instrument transformer and a voltage sensor. A voltage comparator compares the bus voltage with a predetermined threshold voltage set to a voltage lower than a lower limit value of a steady state fluctuation range of the bus voltage and outputs the comparison result to a circuit breaker control section. When the bus voltage is lower than the threshold voltage, the circuit breaker control section locks the control command from the cooperative control section.

Power system control apparatus and power system control method

A light wavefront measuring apparatus () includes a separating element () for separating a flux of light which exits from an optical head () into a first beam and a second beam, a first interference fringe display section () for displaying interference fringes formed from the first beam, a Dove prism () for rotating a wavefront of the second beam around its optical axis (AX), and a second interference fringe display section () for displaying interference fringes formed from the second beam which passed through it. In adjustment of the light source device, position of a collimator () in the optical head () is adjusted in optical axis direction so as to approximate the interference fringe patterns displayed in the interference fringe display sections () each other.

Light wavefront measuring instrument, light wavefront measuring method, and light source adjusting method

An optical recording and reproducing apparatus for optically recording and reproducing information on and from a disk includes a light source for generating a parallel beam. A movable optical system condenses the parallel beam from the light source on the disk, splits the beam into two different beams, and moves in the radial direction of the disk. A split-beam detecting device has two light receiving surfaces which receive part of the two different beams obtained in the movable optical system. A and a control device effects tracking control by moving the movable optical system in the radial direction of the disk in accordance with respective detection signals output from the two light receiving surfaces.

Optical recording and reproducing apparatus having a pickup head

A wavelength selective optical recording and reproducing method includes an optical recording and reproducing step of information composed of time series signals on a recording medium having recording tracks as position series signals with light having a variable wavelength while switching the wavelength between predetermined values.

Wavelength selective optical recording and reproducing method

An optical recording and reproducing apparatus includes a light source for generating a parallel beam. A movable optical system condenses the parallel beam from the light source on the disk, splits the beam reflected by the disk into a first and a second beam, spatially inverts the second beam, and moves in the radial direction of the disk. A first split-beam detecting device has two light receiving surfaces which receive the first beam. A second split-beam detecting device has two light receiving surfaces which receive the second beam inverted in the movable optical system. A control device performs tracking control by moving the movable optical system in the radial direction of the disk in accordance with detection signals output from the first and second split-beam detecting devices.

Optical recording and reproducing apparatus

An optical head for use in an optical information recording/reproducing apparatus includes an optical system comprising a plurality of optical elements including a light-emitting element, and a casing which securely mounts at least part of the optical elements. The casing is provided with a vibration damping material which is effective to damp vibrations of the casing.

Optical head for optical information recording/reproducing apparatus

The present invention relates to an optical recording and/or reproducing apparatus which optically carries out operations of recording and/or reproducing of information on a data carrier, by irradiating a beam from an optical head to the data carrier. In the apparatus according to the present invention, the angle between the optical axis of the beam from the optical head and the surface of said data carrier is detected, and a temperature adjusting device brings about a difference in temperature between both surfaces of the data carrier on the basis of the detected result in respect to the angle. Then, the difference in temperature generates a thermal strain, and this thermal strain functions to cancel the strain which the data carrier has previously had. As a result, the surface of the data carrier is kept on a level, so that this surface can be vertical to the optical axis of the beam from the optical head. Therefore, in the optical recording and/or reproducing apparatus, easily maintained is the right angles between the surface of the data carrier and the optical axis of the beam, and the mechanism for focalizing the beam can be simplified to miniaturize the optical head. Furthermore, no mechanism for making the optical head oscillate is required, as a result, a high-speed accessibility is obtained.

Optical recording and/or reproducing apparatus having a temperature

A magneto-optic information-carrying medium comprises three magnetic layers. A magnetic bias field is generated by a third layer which is premagnetized in the direction parallel to the thickness thereof.

Magneto-optic information-carrying medium including three magnetic layers

A focusing error detecting apparatus comprises an objective lens system for focusing a ray flux on a surface of an optical recording disk, two photo detectors, an optical means including the lens system and a beam splitter, for focusing a ray flux reflected from the optical recording disk so that the ray flux comes to the middle of a space formed between the two photo detectors when the focal point is formed on the optical recording disk, a combination of two interruption/deflection elements and a control device for switching the ray flux transmitted from the optical recording disk at the two positions which correspond to said two photo detectors, two sampling/holding circuits respectively hold differences of output of the two photo detectors in correspondence to the switching operations of the interruption/deflection elements and the control device, and a subtracting circuit for outputting a focusing error signal on the basis of the outputs of the sampling/holding circuit.

Focusing error detecting apparatus with light switching and detector

Provided is an optical recording and reproducing apparatus in which a collimator lens collimates divergent light fluxes from a light source to emit parallel light fluxes and then an objective lens converges the parallel light fluxes onto an information carrier. The collimator lens comprises a first lens having a first predetermined focal distance and a second lens having a second predetermined focal distance which is longer than the first predetermined focal distance. The second lens can be moved in the optical-axis direction so as to adjust the relative position of the collimator lens and the light source.

Optical head including a collimator having lenses of different focal

An information-carrying medium with first, second and third ferromagnetic layers is enclosed in a housing, in which an initializing magnet is disposed. The second layer of the information-carrying medium is magnetized by the initializing magnet premagnetized in a uniform direction and is used as a bias layer.

Information-carrying medium equipment for magneto-optic reading and

An information-carrying medium having the form of a disc is rotated around a central axis. The temperature of the disc is controlled by a temperature-adjusting element facing the surface of the disc.

Optical reading or writing apparatus

Information is recorded by creating recording hole at a predetermined wavelength position on a memory element with a characteristic of wavelength selective optical data storage. Because the memory element is pit-like, it causes diffraction of a light beam transmitted through or reflected by it. The diffracted beams are detected for positioning a beam spot right on the selected memory element.

Wavelength selective optical data storage system

A recording medium for wavelength selective optical data storage has at least one memory element on which information is recorded by creating recording holes on the absorption spectrum thereof. The spectrum has at least one prerecorded hole for identifying the wavelength positions of the recording holes.

Growing community of inventors

Amagasaki, Japan

Michihiro Tadokoro