LED Emitter Optical Gas Sensor Narrow Bandwidth
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Solution Overview
Problem
Conventional optical gas sensors face inefficiencies due to broad light spectra emission by light bulbs, leading to increased energy consumption and reduced battery life in mobile applications, as well as challenges in accurately measuring weakly absorbing gases.
Innovation Solution
An optical gas sensor utilizing LEDs as radiation sources that emit a narrow spectrum of light waves, allowing for separate emission of main and reference signals, with a bandpass filter to minimize irrelevant wavelengths and improve energy conversion efficiency, and a mirror arrangement for extended optical path length to enhance gas detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light bulb is used as the light source, then a broad spectrum of light waves is emitted, but energy consumption increases and heat generation rises
Solution Approach 1:
The patent changes the fundamental parameter of light emission from thermal radiation (light bulb) to electroluminescence (LED). This parameter change enables narrow bandwidth emission at specific wavelengths needed for gas detection, dramatically reducing power consumption and heat generation while eliminating the need for broad spectrum emission and subsequent filtering
Solution Approach 2:
The invention extracts only the necessary wavelength components for gas detection by using LEDs that emit light at specific absorption wavelengths of the target gas. This eliminates the unnecessary broad spectrum components that would require filtering, thereby reducing energy waste and improving measurement efficiency
2Illumination intensity
If a light bulb is used as the light source, then light waves are emitted, but a large percentage of electrical energy is converted into heat
Solution Approach 1:
The patent fundamentally changes the energy conversion mechanism from thermal radiation (where most electrical energy becomes heat) to electroluminescence (where electrical energy is directly converted to light). This parameter change achieves high energy conversion efficiency with minimal heat loss, directly addressing the energy waste problem of conventional light bulbs
3Measurement precision
If bandpass filters are arranged upstream of detectors, then defined wavelengths are detected, but measurement errors occur due to filtered wavelengths
Solution Approach 1:
Instead of using bandpass filters to extract necessary wavelengths from a broad spectrum, the invention directly emits only the necessary wavelengths using LEDs tuned to specific absorption lines of the target gas. This eliminates the filtering step that causes measurement errors while maintaining wavelength specificity and measurement precision
Solution Approach 2:
The patent performs preliminary wavelength selection by choosing LEDs with emission spectra matched to the absorption characteristics of the target gas. This preliminary action ensures that only relevant wavelengths are emitted, eliminating the need for subsequent filtering and preventing measurement errors that would otherwise occur
4Volume of moving object
If the cuvette is made compact, then the device size is reduced, but the optical path length is insufficient for weakly absorbing gases
Solution Approach 1:
The patent employs periodic modulation of the LED emission and uses synchronous detection techniques. This periodic action enables the system to extract weak absorption signals from noise, achieving high measurement precision for weakly absorbing gases in a compact cuvette without requiring an extended optical path length
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
The solution reduces heat generation and power consumption, extends battery life, and enables precise quantitative measurement of gas concentrations, including weakly absorbing gases, while minimizing measurement errors and maintaining accuracy.
Implementation Method 1
The radiation source comprises at least one emitter of light waves, e.g., an LED and is configured to emit light waves of at least one first wavelength and of a second wavelength different from the first wavelength simultaneously as well as separately from one another
Implementation Method 2
Light waves emitted by the light source are more or less strongly absorbed by the respective gas depending on the concentration of the ingredients of the gas mixture, as well as on the absorption wavelengths
Implementation Method 3
A plane mirror on one side and a concave mirror on the other side are arranged at the cuvette in the longitudinal axial direction. Light waves emitted by the light bulb are first repeatedly reflected between the plane mirror and the concave mirror
Data Source
AI summary
An optical gas sensor (1), for quantitatively measuring a concentration of one or more gases, includes a radiation source (2) for emitting light waves (L), a cuvette (3) for holding a gas (G) to be measured, and a detector (4) for measuring light intensities. The light source (2) includes at least one emitter (5) of light waves (L) and is configured to emit light waves (L) of at least one first wavelength and of a second wavelength different from the first wavelength simultaneously or separately from each other. The emitter (5) is further configured to emit a spectrum the full half-life width of which is a maximum 50% of the effective wavelength, and to emit light waves (L) having a controlled beam path. The detector (4) is configured to quantitatively detect an intensity of emitted light waves (L) of the first wavelength and of the second wavelength.