Spherical Surface Acoustic Wave Detector for Hydrogen
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Solution Overview
Problem
Conventional environment difference detectors using planar elastic surface wave elements have limitations in detecting environment differences due to short surface acoustic wave propagation distances and sensitive film thickness requirements, leading to slow detection speeds and potential film damage.
Innovation Solution
An environment difference detector with an elastic surface wave element featuring a substrate with annular and circular paths for surface acoustic wave circulation, a surface acoustic wave exciting/receiving unit, and a sensitive film that changes its elastic nature in response to environmental changes, allowing for longer propagation distances and accurate, quick measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a planar elastic surface wave element is used with a short propagation distance, then the device complexity is reduced, but the measurement precision deteriorates due to insufficient interaction between the surface acoustic wave and the sensitive film
Solution Approach 1:
The patent employs a spherical substrate instead of a planar substrate, allowing surface acoustic waves to propagate along a curved path with extended distance. The spherical geometry enables the wave to travel along a great circle path, significantly increasing the interaction length between the wave and sensitive film while maintaining a compact device form factor.
Solution Approach 2:
The invention transitions from a two-dimensional planar surface to a three-dimensional spherical surface. This dimensional change allows the surface acoustic wave to propagate along a curved trajectory on the sphere's surface, effectively increasing the propagation distance without proportionally increasing the device's linear dimensions.
2Measurement precision
If the surface acoustic wave propagating distance is extended, then the measurement precision improves, but the sensitive film thickness must be increased which slows down detection speed and risks film damage
Solution Approach 1:
By using a spherical substrate, the surface acoustic wave propagates along a curved path that extends the interaction distance with the sensitive film. This curvature-based extension allows for longer propagation distance (e.g., several centimeters) without requiring increased film thickness, thereby maintaining fast detection speed and avoiding film damage risks.
3Measurement precision
If the sensitive film thickness is increased to improve measurement precision, then the detection accuracy improves, but the detection speed becomes slow and the film becomes easily damaged
Solution Approach 1:
The spherical substrate configuration extends the surface acoustic wave propagation distance along the curved surface, enabling sufficient interaction between the wave and a thin sensitive film. This approach achieves high measurement precision while maintaining film integrity and fast response speed, avoiding the need for thick films that would be slow and fragile.
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 enables faster and more accurate detection of environment differences while maintaining a simple design and reducing the risk of failure, as demonstrated by improved sensitivity and resolution in hydrogen concentration measurements.
Implementation Method 1
The bamboo blind-shaped electrode as the surface acoustic wave exciting unit subjects a high-frequency signal supplied from a high frequency generating unit to piezoelectric conversion, and excites a surface acoustic wave on the surface of the substrate
Implementation Method 2
the bamboo blind-shaped electrode as the surface acoustic wave receiving unit converts the surface acoustic wave excited and propagated on the surface of the substrate by the bamboo blind-shaped electrode as the surface acoustic wave exciting unit into a high-frequency signal again by piezoelectric conversion
Implementation Method 3
an elastic surface wave element equipped with a substrate including a surface having at least one annular and circular path along which a surface acoustic wave circulates
Data Source
AI summary
An environment difference detector includes an elastic surface wave element equipped with a substrate including a surface having an annular surface acoustic wave circulating path, a surface acoustic wave exciting/receiving unit exciting a surface acoustic wave along the circular path and receiving the circulated surface acoustic wave, and a sensitive film disposed on the circular path to change an elastic nature in accordance with a change in an adjacent environment, a speed/intensity measuring unit measuring a circulating speed and intensity of the surface acoustic wave from an electric signal generated by the unit when the unit receives the circulating surface acoustic wave, and an environment evaluation unit evaluating an environment adjacent to the sensitive film from at least one of the circulating speed and the intensity measured by the unit.