Optical filter for NDIR gas sensor, optical device and NDIR gas sensor

摘要

Problem to be solved: to provide a high-precision NDIR gas sensor, an optical device and an optical filter for the NDIR gas sensor in the case of using a simplified optical filter.NDIR gas sensorBoard andA multilayer film having a plurality of layers having different refractive indices formed on at least one surface of the substrateOptical filter havingFirst conductor type semiconductive layerAn infrared light receiving and emitting element having an active layer and a second conductivity type semiconductor layerEquipped withMultilayer filmThe structure in which the first and second layers are alternately stacked are included.Active layerContains inassyb1-y (0.1. Leq. Y.leq. 0.2)Optical filter6 μ M to 10 μ In the wavelength range ofIncludes a wavelength region with an average transmittance of greater than or equal to 50% and over12.5 μ M to 20 μ The maximum transmittance in the wavelength range ofAnd12.5 μ M to 20 μ The average transmittance in the wavelength region of M is 5% or more and 60% or less.Diagram