The Tokyo Electric Power Company, Incorporated

Oki Electric Industry Co., Ltd.

Hitachi, Ltd.

Fujitsu Corporation

Nippon Telegraph and Telephone Corporation

Mitsubishi Heavy Industries Limited

Namiki Precision Jewel Co., Ltd.

Fuju Electric Co., Ltd.

Kiyoshi Kurosawa

Kazuomi Shirakawa

Jiro Utsunomiya

Akira Tanaka

Yuji Kojima

Wataru Watanabe

Ryo Nagase

Masao Kawachi

Tadashi Sato

Yoshihiro Konno

Tatsufumi Aoi

Yoichiro Tsumura

Akira Himeno

Kuniharu Kato

Etsunori Mori

Masaru Sasaki

Hajime Hotta

Sadamu Saito

Hisao Matsukura

Masaki Sugawara

Kazuyuki Seino

Genji Takahashi

Akio Hirakawa

Yasuhiko Kudou

Yutaka Kikuchihara

Yoshiharu Hiroki

Yoshinori Shirai

Kiyoshi Fujii

Mamoru Yamada

Iida Saburo

Toshiyuki Kawashima

Ken-ichi Yukimatsu

Masayuki Okyno

A lightning current measuring device is provided with: a polarized light separation element which separates light output from a sensor fiber into horizontal and vertical components having orthogonal planes of polarization, a Faraday rotation angle calculation unit calculating a Faraday rotation angle through arc-sine processing of a digitized signal of the difference between the horizontal and vertical components converted to a signal through photoelectric conversion after separation by the polarized light separation element, amplifiers which amplify the horizontal and vertical components converted to a signal through photoelectric conversion after separation by the polarized light separation element, a Faraday rotation angle calculating unit which calculates a Faraday rotation angle based on a digitized signal of the difference between the amplified horizontal and vertical components, and current value conversion units converting current values based on the calculated Faraday rotation angles.

Lightning current measuring device and lightning current measuring method

A simple constitution together with an easy calibration of output by realizing a fast light intensity detection method is realized without using the carrier signal. An optical sensor, including: a sensor to which light from a light source is lead, and by which light intensity of the light is modulated based on a physical value; light receiving elementsandreceiving two elements of divided light PA and PB having polarized waves which are orthogonally crossing each other; a variable optical attenuator operating light which is received by the light receiving elementsand; and a variable amplifier operating output signals from the light receiving elementsand, wherein both a zero point of a sensor output and sensitivity are calibrated based on a light attenuation factor or an amplification factor which is adjusted when a physical value is detected by calculating a ratio between a sum and a difference of outputs of the light receiving elementsand

Optical sensor, optical current sensor and optical voltage sensor

An influence on a sensor output is suppressed to a minimum degree even in the case when there is a ripple in a light source, thereby improving the measurement accuracy. In an intensity modulation type optical sensor, light from a light sourceis guided to a sensor head, the intensity of the light is modulated on the basis of an alternating current (AC) measured object (for example, a current i) changing with time, the modulated light is received in a light receiving elementand converted into an electrical signal, and a normalized received signal Xs indicating a degree of modulation is acquired from a ratio of an AC component As and a DC component Ds of the electrical signal to thereby acquiring a value of the AC measured object. Further in this invention, a reference signal Vr is acquired by separating and receiving part of light incident on the sensor head, a normalized reference signal Xr is acquired from a ratio of an AC component Ar and a DC component Dr of the reference signal, and the normalized reference signal Xr is subtracted from the normalized received signal Xs, thereby reducing noises and improving the accuracy.

Intensity modulation type optical sensor and optical current/voltage sensor

[Problem] To permit reduction in the temperature dependence of a sensor, which is ascribable to the temperature dependence of the Verdet constant of a sensor fiber, at a low cost. [Means for Resolution] In a prior-art optical sensor fiber of reflection type, reduction in the temperature dependence of a sensor is coped with by, e.g., duplexing a signal processing circuit and a receiving optical system, so as to execute the mean processing of modulation signals, whereas in this invention, the elimination of the temperature dependence of a modulation signal is realized by selecting a ferromagnetic Faraday rotorso that a modulation degree (S) expressed by the ratio between an AC component and a DC component may become constant or within a certain range, so as to especially simplify a configuration and to attain a lower cost.

Method for reducing temperature-dependent error in photocurrent sensor, and photocurrent sensor device

A current measuring apparatus comprises a current detection unitand a photoelectric converter. The current detection unitcomprises an optical fiber sensorextended or looped around a conductor. A reflective filmis attached to one end of the sensorso that light can be reflected by the end of the sensor. The current detection unitfurther comprises a first Faraday element, a light-transmitting birefringent member, a first optical fiber, a second optical fiberand a lens. The Faraday elementrotates a plane of polarization of the incident light through about 22.5&#xb0;. The birefringent memberfunctions to separate the light emitted from the sensorinto an ordinary ray Land an extraordinary ray Lthat are orthogonal to each other, and to transmit linearly polarized light Lemitted from a light source. The lensis provided between the elementand the birefringent member. Focal points of the lens are formed at core portions of an input endof the sensorand an end faceof the first optical fiber. With this arrangement, the number of components is reduced and the apparatus is reduced in size.

Current measuring device

Composite units of an optical semiconductor device and a supporting substrate are disclosed, in which the rear surface of the optical semiconductor device is provided with one or more electrode patterns and the top surface of the supporting substrate is provided with one or more electrode patterns. The optical semiconductor device and the supporting substrate are fixed to each other by once melting and solidifying one or more solder bumps which intervene between the one or more electrode patterns provided on the rear surface of the optical semiconductor device and the one or more electrode patterns provided on the top surface of the supporting substrate. A good grade of accuracy in the mutual geometric position of the optical semiconductor device and the supporting substrate is obtained in a horizontal direction due to a phenomenon called 'the self alignment results' in this specification, in which a molten metal is inclined to become a ball based on surface tension. Methods for mounting an optical semiconductor device on a supporting substrate with a good grade of accuracy in the mutual geometric position therebetween in the horizontal direction, based on the same technical principle, are also disclosed. To realize the foregoing results, each of the composite units of an optical semiconductor device and supporting substrate in accordance with this invention is given various structures specific to each of them, and each of the methods in accordance with this invention is given various steps or processes specific to each of them.

Composite unit of optical semiconductor device and supporting substrate

A light detecting device for reliably detecting weak luminescing at a random position in a predetermined spatial area. The light detecting device has a fluorescent fiber containing a fluorescent coloring matter and a flat or curved concentrator having a primary surface, on which the fluorescent fiber is fixedly arranged with the axis thereof in parallel relationship to the primary surface. A light receiving means is connected to at least one end of the fluorescent fiber.

Light detecting device

An optical switching module has an optical waveguide substrate mounted on an electronic circuit substrate. According to a first aspect of the invention, the optical waveguide substrate has thin-film heaters, and the electronic circuit substrate has trimmable thick-film resistors for adjusting current fed to the thin-film heaters. According to a second aspect of the invention, the optical switching module also has a pair of fiber pigtails butt-coupled to the optical waveguide substrate. The fiber pigtails are secured to the ends of a supporter, which is attached to a heat sink fastened below the electronic circuit substrate. According to a third aspect of the invention, the optical waveguide substrate is mounted in a depression in the electronic circuit substrate. The invention reduces the size of the optical switching module.

Compact optical switching module including thin-film heaters and trimmed

An optical d.c. voltage transformer having an electrooptic medium to which a d.c. electrical field or voltage to be measured is to be applied. The electrooptic medium affects the polarized light from the polarizer by an electrooptical effect to a degree proportional to the strength of the electrical field or voltage. The transformer includes a photodetector for producing an optical signal proportional to the affected light received from the electrooptic medium, a device for converting the optical signal from the photodetector into an electrical signal, a chopper for pulsating the electrical field or voltage to be applied to the electrooptic medium, in terms of time, a detector for demodulating the electrical signal from the converting device in synchronism with the pulsated electrical field or voltage, and an output unit for visually presenting the demodulated electrical signal similar in polarity to the electrical field or voltage to be measured.

Optical d.c. voltage transformer

Growing community of inventors

Tokyo, Japan

Kiyoshi Kurosawa