Photo-acoustic gas sensor with optimal reference path length
AssigneeInfineon Technologies AG
InventorHorst Theuss
Life of this patent
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Abstract
A photo-acoustic gas sensor may include a detector component. The detector component includes a package that defines a reference volume. The reference volume houses a reference gas. The detector component includes a pressure sensing element to measure an amount of pressure in the reference volume. The amount of pressure in the reference volume depends on absorption of a wavelength of light by the reference gas in the reference volume. A sensitivity of the pressure sensing element when measuring the amount of pressure in the reference volume depends on a length of a reference path associated with the reference volume. The detector component includes a reference path structure that causes the length of the reference path to be less than or equal to 0.5 millimeters.
Claims20
A photo-acoustic gas sensor comprising a detector component, the detector component including:
- a package that defines a reference volume housing a reference gas;
- a light inlet window;
- a pressure sensing element to measure an amount of pressure in the reference volume, wherein the amount of pressure in the reference volume is dependent on absorption of a wavelength of light by the reference gas in the reference volume, wherein a sensitivity of the pressure sensing element, when measuring the amount of pressure in the reference volume, depends on a length of a reference path associated with the reference volume, and wherein the length of the reference path is defined by a length from the light inlet window to an interior surface, of the reference volume, that is directly opposed to the light inlet window;
- and a reference path structure that causes the length of the reference path to be less than or equal to 0.5 millimeters, wherein the photo-acoustic gas sensor is configured to have a direct path between an emitter component and the light inlet window for the light to propagate.
A gas sensor, comprising:
- an emitter component including an emitter to emit light at a particular wavelength;
- and a detector component including:
- a light inlet window, a pressure sensing element to measure an amount of pressure in a reference volume of the detector component, wherein the reference volume houses a reference gas, wherein the amount of pressure in the reference volume is defined by absorption of the light by the reference gas, and wherein a sensitivity of the pressure sensing element depends on a length of a reference path associated with the reference volume, wherein the length of the reference path is defined by a length from the light inlet window to an interior surface, of the reference volume, that is directly opposed to the light inlet window;
- and a reference path structure that results in the length of the reference path being less than or equal to 0.5 millimeters, wherein the photo-acoustic gas sensor is configured to have a direct path between an emitter component and the light inlet window for the light to propagate.
A detector component of a gas sensor, the detector component including:
- a package that defines a reference volume, wherein a reference gas is present in the reference volume;
- a light inlet window, a pressure sensing element to measure an amount of pressure in the reference volume, wherein the amount of pressure in the reference volume depends on absorption of a wavelength of light by the reference gas in the reference volume;
- and a reference path structure that causes a reference path, associated with the reference volume, to have a length that is less than or equal to 0.5 millimeters, wherein the length of the reference path is defined by a length from the light inlet window to an interior surface, of the reference volume, that is directly opposed to the light inlet window, wherein the length of the reference path causes a sensitivity of the pressure sensing element to be in a range from 10 millipascals per 100 parts per million (mPa/100 ppm) to 40 mPa/100 ppm, and wherein the photo-acoustic gas sensor is configured to have a direct path between an emitter component and the light inlet window for the light to propagate.
Dependencies are inferred from the claim text.