Patent ID: 7397022

Claim:
A sensor arrangement as a part of a reflection light barrier, said sensor arrangement comprising: a carrier; a photodiode arranged on said carrier; a first light emitting diode arranged on said carrier and adapted to emit a pulsed measuring light beam; a second light emitting diode arranged on said carrier and adapted to emit a reference light beam that is pulsed offset in time relative to the measuring light beam; and a light permeable housing arranged to enclose said photodiode, said first light emitting diode and said second light emitting diode; wherein said second light emitting diode is arranged on said carrier and in said housing such that the reference light beam emitted by said second light emitting diode will be reflected internally by a surface of said housing to be incident onto an upper surface of said photodiode; and wherein said housing, said photodiode, said first light emitting diode and said second light emitting diode are arranged and embodied so that none of the reference light beam emitted by said second light emitting diode will be incident on any lateral side surface of said photodiode.