Optical Gas Sensor External Absorption Path
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Solution Overview
Problem
Conventional optical infrared gas sensors are limited by the short absorption path length due to their compact design, which restricts their sensitivity and makes them unsuitable for integration into portable devices like cell phones and handheld devices.
Innovation Solution
The gas sensor device emits measurement light into a spatial region outside the device, allowing for a significantly longer absorption path, up to several meters, and uses a light detector to measure the reflected light intensity, eliminating the need for internal reflector devices and enabling a more compact, sensitive design suitable for portable devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the absorption path length is increased to improve sensitivity, then the device size and complexity increase due to requiring internal reflector devices
Solution Approach 1:
The patent extracts the measurement process from the device interior by emitting light outside the device housing. The absorption path is established in the external environment between the light emission device and light detector, eliminating the need for internal reflector devices and complex internal optical paths while achieving meter-scale absorption paths.
2Measurement precision
If the absorption path length is increased to improve sensitivity, then the device volume increases
Solution Approach 1:
The patent transitions from three-dimensional internal path folding to one-dimensional external path extension. By emitting light outside the device and using the external space between the light emission device and light detector, the absorption path extends in the spatial dimension without increasing device volume, enabling portable device integration.
3Length of stationary object
If internal reflector devices are used to extend the absorption path, then the device complexity and size increase
Solution Approach 1:
The patent removes the reflector devices from the device interior and replaces them with external environmental surfaces. The light emission device emits measurement light outside the device, which reflects off external objects or surfaces and returns to the light detector, achieving path extension without internal mechanical components.
4Length of stationary object
If the absorption path is extended within the device housing, then the device volume increases
Solution Approach 1:
The patent moves the absorption path from inside the device housing to the external environment. The measurement light travels in the external space between the light emission device and light detector, utilizing external dimensional space rather than internal device volume, thereby achieving long absorption paths in compact devices.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the sensitivity for determining gas concentrations and allows for the integration of gas sensors into portable devices by extending the absorption path length and reducing the device's spatial requirements.
Implementation Method 1
the gaseous component to be measured absorbs light at a characteristic wavelength of λgas in the infrared spectral region
Implementation Method 2
a light detector 80 having at least two measuring channels for measuring the light intensity at the wavelength λgas
Implementation Method 3
a light source 10 that is broadband emitting in the infrared spectral region
Data Source
AI summary
A gas sensor device for determining a molar concentration of a gas to be detected, that absorbs light of a measurement wavelength that is characteristic of the gas in the infrared light region, includes a light emission device emitting measurement light of measurement wavelength into a solid angle region of a light absorption path extending through the gas, and a light detector measuring an intensity of at least one component of the measurement light that has propagated through the light absorption path, the light absorption path extending from the light emission device to an object outside the gas sensor device that at least partially reflects the measurement light to the light detector, and being essentially disposed outside of the gas sensor device, and means for determining the length of the light absorption path. A method for determining a concentration of a gas to be detected is also described.