Asea Aktiebolag

Asea Ab

Christer Ovren

Torgny Brogardh

Bertil Hok

Morgan Adolfsson

Olof Engstrom

Lars Sander

Sture Goransson

Iorgny Brogardh

Anders Persson

Tomas Hidman

Torgny Brogangrdh

Chantal Dubon

The present invention relates to a fiber-optic measuring apparatus for measuring physical quantities, such as position, speed, acceleration, force, pressure, elongation, temperature, etc., comprising at least one optic fiber for conducting light between an electronic unit and a transducer. The transducer comprises a member having at least one luminescent material, and the position of that member with respect to the fiber end is influenced by the quantity being measured, the output signal from the transducer thus being dependent on the quantity being measured.

Fiber-optic measuring apparatus using luminescent material

An optical position-measuring sensor has a monolithic structure which includes at least two masses of photoluminescent material, which on excitation emit photoluminescent light with non-identical spectra. The at least two masses are supported in the sensor by a resilient part (e.g. a beam or diaphragm), the deflection of which determines the wavelength distribution of the luminescent light which is coupled into an optical wave conductor (e.g. a light fiber) terminating in the sensor.

Optical position-measuring sensor

A fiber-optic measuring device for measuring physical quantities, comprising a transducer unit and an electronic unit which are interconnected by means of at least one optic fiber. The measuring transducer unit comprises at least two photoluminescent elements, of which at least one is positioned in the ray path of light from the fiber, at least partly behind another element. The physical quantities to be measured are arranged to influence the light transmission between the photo-luminescent elements. The electronic unit includes at least two light sources having different emission spectra which are so chosen in relation to the absorption and transmission spectra of the photo-luminescent elements that one light source is arranged to excite substantially one of the photo-luminescent elements whereas the other light sources at least partly excite the other element or elements.

Fiber-optic luminescence measuring system for measuring light

A semiconductor component for electrical generation of optical radiation, for example an LED, is provided. The component includes a semiconductor body that contains a first region of material of a first conductivity, a second region of material of a second conductivity type adjacent to the first region; and a PN junction between these regions. The first region has a central part of a material with a first band gap and a peripheral part laterally surrounding the central part of the first region. The material of the peripheral part has a band gap larger than the bang gap of the central part of the first region. The material of the second region has a larger band gap than the band gap of the central part of the first region.

Semiconductor component for generation of optical radiation

A light-generating element, for example an LED, a semiconductor laser or a body of photoluminescent material is arranged to have a temperature-independent output power characteristic by providing it with an optical filter having such a frequency-dependent transmission curve that the amplitude of the signal, emitted by the element, is, after passage through the filter, substantially independent of the temperature of the element.

Temperature compensated light-generating device

A fiber optical measuring device for measuring dynamic movements between a boundary surface of an optical fiber and a boundary surface of a movement-sensing body. The optical fiber is adapted to transmit optical energy to and from the boundary surfaces and at least one of the boundary surfaces includes a photo-luminescent material, the optical energy reflected from the boundary surface of the body being dependent on the relative position between the two boundary surfaces.

Fiber optical measuring device for measuring dynamic movements

A fiber-optic sensor for measuring a physical quantity or sensing changes therein, consists of a transmitter and receiver unit respectively arranged to transmit and receive optical energy and an optical fiber for transmission of said optical energy to and from a sensor located at the measurement point. The sensor has at least one solid body, which is arranged to emit photoluminescent optical energy in at least one wavelength range, and a volume limited by at least two substantially plane-parallel surfaces, the separation of which is smaller than half the coherence length for either the transmitted or luminescent optical energy, whereby an interference pattern will differently affect the transmission of optical energy to the receiver unit as the optical length between said parallel surfaces changes with changes in the physical quantity being sensed.

Fiber-optic luminescence sensor utilizing interference in a thin layer

A device for transforming information in electrical form into optical form, where the optical information consists of light intensity, light polarization or spectral composition varying with time. The transformation of information takes place from electrical into optical form by means of optical modulators, e.g. liquid crystals, and the transformation from optical form into electrical form is arranged to be carried out with photo-detectors, the device comprising components to control or sense said optical modulators in one, two or three-dimensions with time, and to sense or control said photo-detectors. The invention is characterized in that said components consist of one or more circuits with electro-optical feedback, in which at least one optical modulator is located in the ray path between at least one light source, for example a light-emitting diode or laser diode, and at least one photo-detector, for example a photo-resistor or a photo-diode, the photo-detector being connected into at least one electrical circuit, to which the optical modulator is connected in such a way that positive and negative feedback is obtained in a feedback loop. At least one light source is arranged to illuminate one photo-detector through one modulator and the other photo-detector through the other modulator, and one modulator is connected to the electric circuit of the other photo-detector, and the other modulator is connected to the electric circuit of the other photo-detector, thus obtaining a cross connection with electro-optical feedback.

Circuits with electro-optical feedback for display and a digitizer

An optical sensor for detecting changes in physical quantities such as temperature, position, force, level, pressure, flow, acceleration, magnetic or electrical field strength or mechanical deformation, includes a luminescent material built up of atomically localized luminescence centers, included as a solid solution in an amorphous or mono-crystalline bonding material.

Optical sensor having atomically localized luminescence centers

A fiber optical luminescence measuring system for measuring a change in a physical quantity employs a transmitter/receiver unit and a sensor unit for the physical quantity optically linked by at least one optical fiber. The sensor unit is arranged to emit luminescent light with at least two different decay time constants, where the quotient between the intensities of emitted luminescent light having the different decay times corresponds to a measure of the quantity to be measured.

Fiber optical luminescence measuring system for measuring physical

A fiber optical measuring apparatus suitable for measuring physical quantities such as position, speed, acceleration, force, pressure, elongation, temperature, etc., comprises at least one optical fiber for conducting incident light between an electronic unit and a sensor, the sensor comprising at least one luminescent element. The measuring apparatus is characterized in that the physical quantity to be measured is arranged to influence the position of an optical spectral filter, for example of absorption or interference type, relative to the optical fiber in the sensor and/or relative to said luminescent element, and that said spectral filter is arranged to be situated, to a greater or lesser extent, between the end surface of the optical fiber and at least one of the luminescent elements.

Fiber optical luminescence sensor for measuring mechanical displacement

A sensor element adaptable for measurement of a physical parameter formed of a crystalline material and emitting luminescent spectra upon excitation by light spectra and the influence of said physical parameter. A first layer emitting luminescent spectra is formed of a semiconductor material containing dopant providing shallow energy levels and recombination centers with a concentration between 10.sup.15 to 10.sup.18 cm.sup.-3, and sandwiched between second and third layers of semiconductor material having low absorption for light excitation of the first layer, and the respective lattice constants of the second and third layers being substantially coincidental with the lattice constant of the first layer. The sensor element is formed of GaAs for the substrate and AlGaAs for the semiconductor layers, with appropriate variation in the concentration Al, Ga, and As for the various layers. Generally, the energy band gap of the layers sandwiching the luminescent emitting layer are higher than that of the emitting layer. In a modified embodiment, GaAs is used as the luminescence emitting layer with covering semiconductor layers of AlGaAs, with appropriate variation in the concentration of Al, Ga and As. In a further modification an additional semiconductor layer of AlGaAs is sandwiched between the active semiconductor layer and a non-active semiconductor layer to reduce or eliminate a shift in the wavelength emission of the sensor element.

Optically excitable luminescent sensor elements

An hermetic seal at a smooth interface between a gallium arsenide body and a glass body is effected without organic or inorganic binders by thermally bonding the bodies at the interface while ensuring that the oxygen concentration at the interface is so low that there is no optically detectable variations in color of the gallium arsenide close to the interface.

Hermetic sealing of gallium arsenide components

A fiber-optical measuring apparatus for measuring magnetic fields, current, position, and various mechanical quantities consists of a transducer connected to a measuring electronic unit via at least one optical fiber, and the transducer comprises a magneto-optical modulator with a domain-producing magnetic material. The transducer is provided with at least two optical filters, of which at least one filter is positioned in the ray path on one side of the magneto-optical modulator and at least one other filter is positioned in the ray path on the opposite side of the modulator.

Fiber-optical measuring apparatus

A fiber optical measuring device for measuring primarily electric voltage or magnetic field, comprises a transducer having a sensor element, the transducer being connected by means of at least one optical fiber to a measuring electronic unit provided with at least two light sources having different emission spectra for excitation of photo-luminescence in the sensor element and at least one photo-detector for detection of photo-luminescene emanating from the sensor element. The sensor element includes at least one luminescent layer arranged so that light from said optical fiber is arranged to fall towards the surface of the layer. Between the end surface of the optical fiber in the transducer and the surface of the luminescent layer, there is arranged at least one optical filter perpendicular to the ray path of the light. The luminescent layer is provided with at least two electrodes to generate, in the layer, a lateral electric field for the purpose of accelerating charge carriers which are excited by light emitted from the measuring electronic unit and transmitted to the luminescent layer via the optical fiber and through at least one of the filters.

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Vaster.ang.s, Sweden

Christer Ovren