Elmos Semiconductor Ag

Wolfram Budde

Erhard Muesch

Erhard Müsch

Wolfgang Büsser

Andreas Kribus

Robert Brands

The device for ambient light compensation for use in optical sensors exposed to both useful light and ambient light comprises at least one first photodiode and at least one second photodiode, the at least one first photodiode being adapted to be exposed to substantially the same useful light and ambient light as the at least one second photodiode. The device further comprises a current mirror circuit having an input and an output, the at least one first photodiode being connected to the input of the current mirror circuit, and the at least one second photodiode being connected to the output of the current mirror circuit. The current mirror circuit comprises a lowpass filter connected between the input and the output of the current mirror circuit. The output of the current mirror circuit provides an output signal representing the useful signal compensated for ambient light.

Device for ambient light compensation for optical sensors exposed to both useful light and ambient light

An inductive position sensor, which in particular is a rotational angle sensor, is provided with two first transmitter units for the generation of two site-dependent first alternating fields having the same carrier frequency, and at least one oscillating circuit arranged in or on an element which may be moved within the alternating field and the position of which is to be determined. The oscillating circuit can be energized by the total alternating field and generates a oscillating-circuit alternating field having the same carrier frequency as the first alternating fields. The position sensor is further provided with at least one receiver unit which receives the oscillating-circuit alternating field, and an analysis unit for determining the phase shift between the oscillating-circuit alternating field and at least one of the two first alternating fields, wherein the two first alternating fields may each be generated by a carrier frequency signal on which substantially identical, substantially 90&#xb0; phase-shifted modulation signals are modulated. Each carrier frequency signal may be generated by application of a square-wave alternating voltage to the first transmitter units, the repetition frequency of said voltage being equal to the carrier frequency. The modulation signal is a pulse density signal having a pulse density changing over time for generation of a signal development having a substantially sine or cosine wave form. The square wave signal is applied to the first transmitter units for the duration of the pulse density signal.

Inductive position sensor

A device for detecting the angle of incidence of radiation on a radiation incidence surface () comprises at last two first pairs () of photodiodes comprising first photodiodes () arranged along a first axis () and connected in series in a pair-wise manner. Each of the first photodiodes () comprises a space-charge zone () having a space-charge zone face () oriented towards the radiation incidence face (). Further, the device is provided with a a shading mask () arranged at a distance () above the space-charge zone faces () of the first photodiodes () and comprising radiation-transmitting areas (). Each radiation-transmitting area () is assigned to the space-charge zone faces () of the two first photodiodes () of a first pair () of photodiodes. When viewed in the direction of the normal of the radiation incidence face (), the degree of overlapping between a radiation-transmitting area () and its assigned space-charge zone faces () in the direction of the first axis () is different for at least two of the first pairs () of photodiodes. The device also comprises an evaluation unit () for monitoring the photocurrent and/or the photovoltage of each first photodiode () of each first pair () of photodiodes and for detecting, on the basis of a comparison of the photocurrents and/or the photovoltages, the angle of incidence under which the component of the radiation which in the projection is directed parallel to the first axis () impinges on the radiation incidence face ().

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Wesel, Germany

Wolfram Budde