UV LED Gas Sensor with Reflecting Walls for Ozone Detection
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Solution Overview
Problem
Current ozone detectors face challenges in accurately detecting small ozone concentrations due to size limitations, sensitivity to other gases, and calibration issues, and often require large mercury lamps with limited lifetimes.
Innovation Solution
A compact UV LED-based system with a chamber having reflecting walls and a computer-controlled UV source and detector, operating in high power pulse mode to determine ozone presence and concentration in a sample gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mercury discharge lamps are used for UV light absorption detection, then ozone detection capability is achieved, but device size becomes large and operational lifetime is limited
Solution Approach 1:
The patent changes the fundamental parameter of the UV light source from mercury discharge lamps to LED technology, operating at different wavelengths (254nm and 365nm). This parameter change enables compact size while maintaining ozone detection capability through differential absorption measurements at multiple wavelengths
Solution Approach 2:
The patent replaces the mechanical/electrical mercury discharge lamp system with a solid-state LED-based optical system. This substitution eliminates the need for large lamp housings and associated mechanical components, achieving compact detector design while extending operational lifetime
2Measurement precision
If large chamber size is used for UV absorption detection, then small levels of ozone can be detected, but device complexity and size increase
Solution Approach 1:
The patent employs periodic pulsed illumination at two different wavelengths (254nm and 365nm) to enable differential absorption measurements. By alternating between wavelengths and comparing absorption differences, the system achieves high sensitivity for small ozone concentrations without requiring large chamber volumes
Solution Approach 2:
The patent adds the dimension of wavelength differentiation by using dual-wavelength LED illumination. This transforms the detection approach from single-wavelength absorption measurement to multi-wavelength differential measurement, enabling compact chamber design while maintaining sensitivity to small ozone levels
3Measurement precision
If semiconductor devices are used for ozone sensing, then sensitivity to ozone is achieved, but sensitivity to other gases increases causing calibration issues
Solution Approach 1:
The patent uses excessive action by illuminating at both 254nm and 365nm wavelengths simultaneously or alternately. Ozone absorbs strongly at 254nm while other gases have different absorption characteristics at this wavelength. By measuring absorption at both wavelengths and analyzing the differential response, the system achieves selective ozone detection despite the presence of other atmospheric gases
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 system provides accurate and compact ozone detection, overcoming size and sensitivity limitations of existing technologies, with improved calibration and reduced maintenance needs.
Implementation Method 1
The detectors that operate based on ozone light absorption take advantage of the Beer-Lambert absorption law of ultraviolet (UV) light passing through ambient gas in a chamber that contains ozone. Since ozone strongly absorbs UV radiation, a concentration of ozone can be inferred from a measured amount of UV absorption.
Implementation Method 2
an ultraviolet detector mounted on the first interior side of the chamber... acquiring data corresponding to an intensity of ultraviolet radiation detected by the ultraviolet detector
Implementation Method 3
The chamber can include reflecting walls and/or structures configured to guide ultraviolet light
Data Source
AI summary
A solution for evaluating a sample gas for a presence of a trace gas, such as ozone, is provided. The solution uses an ultraviolet source and an ultraviolet detector mounted in a chamber. The chamber can include reflecting walls and/or structures configured to guide ultraviolet light. A computer system can operate the ultraviolet source in a high power pulse mode and acquire data corresponding to an intensity of the ultraviolet radiation detected by the ultraviolet detector while a sample gas is present in the chamber. Using the data, the computer system can determine a presence and/or an amount of the trace gas in the sample gas.