Asea Aktiebolag

Iorgny Brogardh

Christer Ovren

Morgan Adolfsson

Bertil Hok

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

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

Iorgny Brogardh