INFRARED GAS SENSOR

PROBLEM TO BE SOLVED: To provide an inexpensive infrared gas sensor capable of accurately detecting a gas component. SOLUTION: The infrared gas sensor includes: an infrared light source 10 for irradiating infrared light with a center wavelength λ0; a multiple reflection optical system 20 for multiply reflecting the infrared light; and a light receiving sensor 30. The multiple reflection optical system 20 includes a multilayer reflective film 22 alternately laminated with a low refractive index layer whose refractive index is nLand a high refractive index layer whose refractive index at the wavelength λ0is nH(where nH>nL). In the infrared gas sensor, a gas to be detected is introduced into an internal space S formed in the multiple reflection optical system 20, the gas to be detected absorbs light of a specific wavelength while the infrared light is being multiply reflected, and then the absorbed light is emitted, and measured by the light receiving sensor 30. COPYRIGHT: (C)2010,JPO&INPIT