| CPC G01N 21/3504 (2013.01) [G02B 6/4215 (2013.01); G02B 6/4298 (2013.01); G01N 2201/08 (2013.01)] | 15 Claims |

|
1. A non-dispersive infrared gas sensor comprising:
an optical waveguide made of a gas-permeable polymer material that gas can penetrate through free volume in the gas-permeable polymer material;
a light source for emitting an optical signal to the optical waveguide;
a photodetector for detecting the optical signal from the optical waveguide; and
one or more band pass filters in front of the photodetector, which selectively pass optical signals of different wavelengths,
wherein the optical signal travels through the optical waveguide by total internal reflection, and contacts a gas particle penetrating the optical waveguide; and
wherein the one or more band-pass filters comprise a filter that passes infrared light of a wavelength that has no gas absorption characteristics and is usable as a reference filter to be compared with a measurement result.
|