Abstract: A device having a light emitter coupled to direct light to a portion of a photodetector to provide Built-In Test Equipment (BITE) capability for an optical sensor. A light emitting diode and a photodiode are mounted side by side on the upper surface of a conventional header with suitable electrical connections bonded thereto. A prismatic light bridge member overlies the light emitting diode and extends to cover a portion of one corner of the photodetector. This member serves as a light conduit, directing virtually all of the light from the emitter to the detector by virtue of the near total internal reflection of the surfaces of the light conduit member. An outer enclosure having a transparent glass window serves to seal and protect the respective elements while permitting external radiation to reach the photodetector.Alternative embodiments provide for coupling of light from a single emitter or a plurality of emitters to a single associated photodetector.

Abstract: A multiple gas analyzer is disclosed utilizing the infrared absorption principle for determining the quantity of two or more gases with a sample tube and a reference tube in parallel orientation with an infrared source between one end of the two tubes, and an infrared detector assembly between the other end of the tubes. Immediately opposed to each end of the tubes are a pair of mirrors, one being a transmitting mirror remote from the infrared source and directing the infrared beam in parallel paths through the reference tube and sample tube, and a receiving mirror opposite the infrared detector assembly to focus the infrared beam after passing through the tubes on to the infrared detectors.