Surface Acoustic Wave Sensor With Porous Liquid Isolation
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Solution Overview
Problem
The existing surface acoustic wave sensors face issues with damage from direct liquid exposure, accuracy in measurement, high manufacturing costs, and difficulty in detecting analytes due to saturation and volatilization, especially when dealing with high-concentration samples.
Innovation Solution
A surface acoustic wave sensor design incorporating a porous base member that allows liquid infiltration and holds it through capillary phenomenon, combined with a reaction-region thin film and sealing structure to prevent electrode contact, enabling accurate and cost-effective detection of analytes without direct liquid exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor surface is uncovered to allow direct liquid exposure for measurement, then measurement accuracy is improved, but the sensor surface is susceptible to damage from direct liquid contact
Solution Approach 1:
A porous membrane is introduced as an intermediary layer between the liquid sample and the sensor surface. The membrane allows liquid to pass through while protecting the sensor surface from direct contact with the liquid, thus maintaining measurement accuracy while preventing surface damage
Solution Approach 2:
A porous membrane is used to allow liquid infiltration while protecting the sensor. The porous structure enables liquid passage for measurement purposes while the membrane itself acts as a protective barrier against direct liquid exposure
2Reliability
If a sealing structure is added to protect electrodes from liquid contact, then electrode reliability is improved, but manufacturing cost increases
Solution Approach 1:
The porous membrane serves multiple functions simultaneously: it protects the sensor surface from liquid damage, prevents electrode contact with liquid, and allows liquid passage for measurement. This multi-functionality eliminates the need for separate sealing structures, reducing manufacturing complexity and cost
3Measurement precision
If liquid is allowed to remain on the sensor surface for measurement, then measurement accuracy is improved, but liquid volatilization causes measurement errors over time
Solution Approach 1:
The porous membrane acts as an intermediary that holds liquid through capillary action, preventing rapid volatilization. This maintains liquid presence on the sensor surface for extended measurement periods without the time-related errors caused by volatilization
4Difficulty of detecting and measuring
If high concentration liquid samples are introduced directly onto the sensor surface, then detection sensitivity is improved, but saturation occurs making analyte detection difficult
Solution Approach 1:
The porous membrane controls liquid infiltration and distribution, preventing saturation of the sensor surface even when high concentration samples are introduced. This maintains the sensor's ability to detect analytes accurately across a wide range of concentrations
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 sensor achieves simple and accurate measurements, prevents saturation, and reduces manufacturing costs by maintaining the liquid within the porous base member, allowing for reliable detection of analytes even at high concentrations.
Implementation Method 1
a porous base member which is disposed at a propagation path of the surface acoustic wave and which allows liquid to infiltrate into an inside thereof and a surface thereof and holds the liquid thereinside
Implementation Method 2
a piezoelectric element substrate that propagates a surface acoustic wave
Implementation Method 3
an interdigitated array electrode (Inter Digital Transducer; IDT) used to generate a surface acoustic wave (acoustic surface wave) on a piezoelectric element substrate and to detect a surface acoustic wave
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A surface acoustic wave sensor of the invention includes: a piezo element that propagates a surface acoustic wave; an electrode that carries out conversion of an electrical signal and a surface acoustic wave; and a porous base member into which liquid infiltrates and which comes into contact with the piezo element.