Gas Sensor Using Ionic Liquid and Surface Plasmon Resonance
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Solution Overview
Problem
Infrared light absorption type gas sensors require a large optical system, while surface plasmon resonance sensors struggle to measure gases with small molecular weights like CO2 due to their size constraints and refractive index proportionality.
Innovation Solution
A gas sensor configuration featuring a metal layer with a prism and a gas-absorbing liquid that changes dielectric constant, allowing detection through surface plasmon resonance phenomena without a light absorption path, enabling the measurement of gases with small molecular weights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an infrared light absorption type gas sensor is used, then gas detection capability is achieved, but the optical system size increases
Solution Approach 1:
The invention extracts and eliminates the light absorption path component from the optical system by adopting surface plasmon resonance detection. This removes the need for long optical paths and complex light absorption structures, thereby reducing the overall sensor size while maintaining gas detection capability through a different physical mechanism.
Solution Approach 2:
The invention changes the detection parameter from light absorption intensity to surface plasmon resonance characteristics. By measuring changes in resonance conditions rather than light absorption, the system achieves gas detection without requiring a large light absorption path, thus resolving the size constraint.
2Volume of stationary object
If a surface plasmon resonance gas sensor is used to reduce size, then optical system size is reduced, but detection of gases with small molecular weight such as CO2 becomes difficult
Solution Approach 1:
The invention introduces a gas-absorbing liquid as an intermediary between the target gas and the surface plasmon resonance sensor. The liquid selectively absorbs gases with small molecular weights like CO2, concentrating them and enhancing their effect on the dielectric constant, thereby enabling detection of these gases despite the sensor's small size.
Solution Approach 2:
The invention changes the detection approach by measuring dielectric constant changes in the gas-absorbing liquid rather than directly measuring the gas properties. This parameter transformation allows the sensor to detect gases with small molecular weights that would otherwise be difficult to detect with conventional surface plasmon resonance methods.
3Device complexity
If surface plasmon resonance is used for gas detection, then sensor size is reduced, but the ability to measure gases with small molecular weight is lost
Solution Approach 1:
The gas-absorbing liquid serves as a mediator that bridges the gap between the simple surface plasmon resonance sensor and the diverse range of detectable gases. By selecting different absorbing liquids with specific affinities, the sensor can be adapted to detect various gas types including those with small molecular weights, thereby enhancing versatility without increasing device complexity.
Solution Approach 2:
The invention creates a universal detection platform where the same surface plasmon resonance sensor structure can detect multiple gas types by simply changing the gas-absorbing liquid. This multi-functional approach allows a single compact device to serve multiple detection purposes, improving adaptability while maintaining simple device architecture.
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 configuration reduces sensor size and enables effective detection of gases with small molecular weights by measuring changes in light intensity due to surface plasmon resonance, overcoming previous size and measurement limitations.
Implementation Method 1
a detector configured to detect the gas based on a change in light intensity of the exit light by a surface plasmon resonance phenomenon that occurs in the metal layer
Implementation Method 2
a gas absorbing liquid provided on a surface of the metal layer, and capable of absorbing the gas
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A gas sensor is proposed, which can detect a gas by a novel configuration while reduction in size is achieved. The gas sensor (1) does not need a light absorption path as in a prior art so that the size can be reduced correspondingly. Further, in the gas sensor (1), a gas is absorbed in an ionic liquid (IL), and a dielectric constant of the ionic liquid (IL) that changes by absorbing the gas can be measured according to a change in light intensity that occurs by a surface plasmon resonance phenomenon in a metal layer (7). Thus, the gas sensor (1) including the novel configuration that can detect a gas based on the change in the light intensity can be realized.