US 2019/0094134 A1 · Compact Optical Gas Sensor with Spatial and Spectral Referense

Abstract

Provided is a method for sensing gases using a compact optical gas sensor, a method for manufacturing same and a method for performing measurement of gas concentration using the optical absorption signal. The sensor design features a two-mirror geometry with long optical path. The sensor utilizes both spectral and optical reference channels. The reference channels ensure long-term stability of the sensor, which makes the design especially suitable for demanding environments requiring high reliability over extended period of time. The sensor operation is based on absorption of infrared light by a gas volume. In order to accurately determine the gas concentration, the absorption of the light that passed through the gas volume is compared with the absorption of the light of a different wavelength and absorption of light that traveled a short light path. A dual-color LED is used as a two-wavelength compact radiation source. The LED changes the emission wavelength as the excitation current is changing direction. The design is applicable to sensors for wearable gas alert devices, stationary leak detection, air quality monitoring, and any other field of applications that requires a specific gases' concentration detection.

Claims11

Dependent claims

A compact low-power Near-Infrared Absorption sensor for detecting gaseous species in the air, comprising:

a dual-color infrared light emitting diode operating under first and second directions of the current conduction depending on the electric bias applied to its terminals at consequent instances of time and producing infrared radiation of a first wavelength when biased to conduct electric current of a first direction, and producing infrared radiation of a second wavelength when biased to conduct electric current of a second direction;
at least one spherical mirror;
at least one flat mirror;
at least one broadband infrared detector with a bandwidth that includes at least the first and the second said wavelengths;
the said sensor further designed in such a way that at least one of the said broadband detectors is measuring the intensity of the light produced by the said light emitting diode both at the first and the second wavelengths, after the said produced light travels a first optical path inside the said sensor, the said first optical path created by the arrangement of the said mirrors and exceeding in length the physical dimension of the said sensor at least by a factor of three.

2 more elements

Dependencies are inferred from the claim text.

Compact Optical Gas Sensor with Spatial and Spectral Referense

Life of this patent

Compact Optical Gas Sensor with Spatial and Spectral Referense

Life of this patent

Abstract

Claims11