Patent ID: 8766154

Claim:
An opto-electronic measuring arrangement that is largely independent of extraneous light, comprising a transmission light source and a compensation light source, which sequentially emit clocked phased light, wherein the light emitted by each is phase-shifted with respect to the other, an optical receiver with a photodiode for receiving light that contains clock synchronous measurement signal transmitted by the light sources, and with an amplifier unit for amplifying a measurement signal current based on the received measurement signal, a clock generator for generating a clock signal, a demodulator for clock synchronous evaluation of the measurement signal current, a controllable current source for generating a clocked transmission control current for the transmission light source, a controllable compensation current source for generating a clocked compensation control current for the compensation light source, and a controller unit for generating at least one control signal for the controllable current source and/or compensation current source, wherein the controller unit is designed such that the amplitude of the light intensity of the compensation light source and/or the transmission light source is controllable by controlling the compensation control current and/or the transmission control current in such manner that a clock synchronous signal difference arising between the light emitted by the transmission light source and the light emitted by the compensation light source is reduced to zero, characterized by a controllable basic coupling current source for generating a clocked basic coupling control current, a basic coupling light source that is different from the transmission light source and is supplied with the basic coupling control current and transmits light directly to the optical receiver; the basic coupling control current is set in such manner that a desired sensitivity of the measurement arrangement is achieved and/or a desired resting value of the controller unit is adjustable, wherein in the absence of an object to be detected the controller unit controls the transmission light source and/or the compensation light source in such manner that the measurement signal received from the basic coupling current source is adjusted, wherein the controllable current source for generating a clocked transmission control current and the controllable basic coupling current source for generating a clocked basic coupling control current are clocked with the clock signal of the clock generator, and the controllable compensation current source for generating a clocked compensation control current is clocked with the inverted clock signal of the clock generator.