Asea Aktiebolag

Morgan Adolfsson

Torgny Brogardh

Christer Ovren

Sture Goransson

Bertil Hok

Iorgny Brogardh

Anders Persson

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

The invention is directed to an optical fiber device for measuring of current and/or voltage, including at least one light conductor for transmitting optical signals between an optical transducer and light generating and light processing circuitry, respectively. A sensed electrical measuring signal is transmitted to a transducer for conversion to a mechanical movement which modulates the light flux received by the transducer.

Optical fiber measuring devices

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.

Fiber optical measuring device for measuring electrical and magnetic

The invention relates to a measuring device for measuring physical and/or chemical quantities, comprising a measuring transducer and an evaluating electronic unit interconnected by at least one light-conducting fiber, said evaluating electronic unit comprising one or more light sources for transmitting light via said fiber/fibers to at least one sensor element, forming a part of said transducer, said evaluating electronic unit also comprising one or more light detectors for detecting light emitted from said sensor element(s). The invention is characterized in that said at least one sensor element possesses a non-linear relationship between the incident light intensity illuminating the sensor element and the intensity of the light emitted from the sensor element, that said light source/light sources are arranged to emit light having at least two, non-identical light intensities, and that at the same time said detector/detectors are arranged to measure the light coming from the sensor element.

Fiber optical measuring device, employing a sensor material with a

The invention relates to a fiber optical measuring device for measuring physical quantities such as temperature and pressure, comprising a measuring transducer comprising a sensor material, an electronic unit comprising an evaluating electronic system, light sources and photo-detectors, and one or more optical fibers which connect said transducer to said electronic unit. The invention is characterised in that the sensor material has optical properties dependent on the modulating frequency of the light, such as absorption, reflection or luminescence; that the light from the electronic unit is arranged to be modulated by one or more frequencies; that at least one of these frequencies lies within the frequency range where the optical properties of the sensor material are influenced by at least one of said physical quantities; and that the modulating amplitude and/or the modulating phase position of the light emanating from the sensor material is/are arranged to be detected in the electronic unit at at least one of said modulating frequencies.

Fiber optical measuring device with a frequency sensitive transducer

A capacitive transducer indicates the value of a physical quantity to be measured and is constructed with two spaced electrically conducting plates movable relative to one another in response to a mechanical signal representative of the physical quantity to be measured to generate an electrical signal in response thereto with the transducer capacitor being actuated and de-actuated to be respectively responsive and non-responsive to the mechanical signal in accordance with pre-designated time intervals. The electrical signal in accordance with the capacitance of the transducer capacitor is integrated to provide an output signal when the integrated signal exceeds a reference value.

Integrated capacitive transducer

The invention relates to an optical measuring device for measuring physical or chemical quantities which device employs at least one light source, such as a light-emitting diode, in optical connection with a sensor, the spectral properties of which (e.g. the absorption or luminescence spectrum) are adapted to be changed by the quantity being measured, and at least one light detector (e.g. a photo-diode or a photo-transistor) for receiving the output signal from the sensor. The invention is characterized in that the measuring signal is adapted to be obtained by spectral analysis, and that this spectral analysis is adapted to be performed by varying the spectral distribution of the light source (the light-emitting diode) or maintaining said distribution constant, and/or by varying the sensitivity spectrum of the light detector or maintaining said spectrum constant, and that this control of the emission spectrum and the sensitivity spectrum is adapted to be carried out by a periodic controlling of the temperature of the light source and of the light detector, respectively.

Optical measurement system for spectral analysis

The invention relates to a fiber-optically coupled measuring device which has an optically energized transducer section which produces signal information in an optical form, the energy supply for the transducer section and the signal information therefrom being transmitted via a light guide fiber. The signal information is transmitted to a receiver at a location remote from the transducer section, the signal information being modified in response to electrical signals fed to a light emitting component of the transducer section.

Fibre optic measuring device with electrically controlled

The invention relates to a fiber optical device for measuring physical magnitudes such as force, elongation, pressure, acceleration, temperature, etc., comprising a transducer unit and an electronic unit, in which the quantity to be measured is supplied to the transducer unit to affect the resonance frequency of an oscillating body included in the tansducer unit by changing the dimensions, mass, density, modulus of elasticity and/or mechanical stress of the body. A property of the body oscillation, such as frequency, phase position and/or amplitude, is used as a value of the quantity to be measured. The oscillations of the body are detected optically by means of a fiber optical position/movement detector.

Fiber optical devices for measuring physical phenomenon

The invention relates to a measuring device having a transmitter side and a receiver side, arranged for signal transmission from the transmitter side to the receiver side via an optical connection. The transmitter side comprises members for combining an incoming measuring signal with a signal from a reference voltage source to two different signals, arranged to be transmitted to the receiver side via each of two parallel optical channels. The receiver side comprises means for receiving the two transmitted signals and for controlling the amplification in the signal paths with a view to obtaining compensation for variation of parameters included in the two channels and other elements in corresponding signal paths. In addition, the receiver side includes a device which, from the two transmitted signals, forms a signal (U.sub.ut) independent of the input measuring signal of the transmitter side.

Measuring device with optical signal transmission

A measuring device has a transmitter side that is connected to a receiver side over an optical transmission link. The transmitter side receives an input measurement signal from a transducer and applies the input signal to an adder that also receives a feedback signal from the receiver side. The adder generates a comparison signal that corresponds to the difference between the input signal and the feedback signal. The comparison signal is applied to a regulator on the receiver side. The regulator generates the feedback signal and an output signal having a magnitude corresponding to the magnitude of the input signal. Amplification of the feedback signal on the receiver side is controlled by time division or frequency division calibration signals, so that the total amplification of the feedback signal between the adder and the regulator is held constant.

Measuring device for transmitting measuring signals via an optical link

In a stabilized fiber optical measuring device for measuring dynamic transients of physical magnitudes, a transducer acted upon by the physical magnitude to be measured receives light transmitted by an optical fiber from a light generator and transmits an optical signal to an optical detector. The transducer modulates at least part of the optical input signal such that the optical output signal therefrom contains at least one measuring component representing the magnitude to be measured and at least one stabilization component. The optical output signal is detected and the measuring component and the stabilization component are separated from one another and respective electrical signals generated such that the dependence of the measuring signal on instabilities in the measuring device can be compensated by a compensating signal. The transducer also attenuates the optical input signal in dependence on the magnitude of the measuring component.

Growing community of inventors

Vaster.ang.s, Sweden

Morgan Adolfsson