Patent ID: 8158946

Claim:
A Non-Dispersive Infrared (“NDIR”) gas sensor for detecting the presence of a chosen gas in a sample chamber, comprising: a mechanical housing comprising: a can having a plurality of inner reflective surfaces; and a header housing affixed to the can having a top surface with a first window and a second window formed in the top surface and a bottom header, said bottom header comprising: a plurality of bottom header reflecting surfaces; a first mirror for reflecting radiation passing from the can through the first window toward a first bottom header reflecting surface of the plurality of bottom header reflecting surfaces; a second mirror for reflecting radiation passing from a last bottom header reflecting surface of the plurality of bottom header reflecting surfaces through the second window toward the can; wherein radiation is bounced off the plurality of bottom header reflecting surfaces so as to create a radiation path length that is substantially greater than the distance between the first and the second mirrors; a Microelectronic Mechanical System (“MEMS”) source affixed to the top surface that emits radiation when power is applied to it; a reference detector that produces a reference output; a signal detector that produces a signal output; and a microprocessor that receives the reference output and the signal output; wherein each of the reference detector and the signal detector have an identical narrow band pass filter with the same Center Wavelength (“CWL”), Full Width Half Maximum (FWHM) and transmittance efficiency at the CWL; and wherein the reference detector and the signal detector are affixed to the top surface so that the plurality of inner reflective surfaces and the radiation path length create a signal channel path length detected by the signal detector that is greater than a reference channel path length detected by the reference detector.