Patent ID: 8546740

Claim:
A sensor apparatus for optically detecting an object, the sensor apparatus comprising: a base plate; a first detection space; a first light transmitter configured for emitting a first illumination light, said first light transmitter mounted on said base plate; a first light receiver configured for receiving a first measurement light formed from at least a partial backscattering of the first illumination light by the object in said first detection space, said first light receiver mounted on said base plate adjacent said first light transmitter, said first light receiver configured for outputting a first output signal; a second light transmitter configured for emitting a second illumination light, said second light transmitter mounted on said base plate; a second detection space; a second light receiver configured for receiving a second measurement light formed from at least a partial backscattering of the second illumination light by the object in said second detection space said second light receiver mounted on said base plate adjacent said second light transmitter, said second light receiver configured for outputting a second output signal; at least one of the first measurement light and the second measurement light including a scattered light produced by partial or complete scattering of the first illumination light at the object; a subtraction unit having an input side coupled to said first light receiver and said second light receiver, and an output side providing a difference signal formed by a difference between the first output signal of said first light receiver and the second output signal of said second light receiver; and an evaluation unit connected to said output side of said subtraction unit to receive the difference signal between the first output signal of said first light receiver and the second output signal of said second light receiver.