Surface Acoustic Wave Sensor Layout for Higher Analyte Sensitivity
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Solution Overview
Problem
Conventional sensor apparatuses using surface acoustic wave devices face difficulties in detecting analyte liquid constituents with high sensitivity due to inadequate concentration of surface-acoustic-wave energy on the reaction section, which is not positioned low enough relative to the IDT electrodes.
Innovation Solution
The sensor apparatus is designed with the reaction section located at a lower level than the IDT electrodes, allowing for concentrated surface acoustic wave energy on the immobilization film, enhancing detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the reaction section is positioned at the same level as the IDT electrodes, then the device structure is simple, but surface-acoustic-wave energy cannot be concentrated on the reaction section, resulting in low detection sensitivity
Solution Approach 1:
The patent introduces a vertical dimension (depth) to the device structure by forming a groove in the substrate. The reaction section is positioned at a lower level than the IDT electrodes, creating a depth difference that enables surface-acoustic-wave energy concentration. This dimensional change allows the wave energy to be focused on the reaction section, thereby improving detection sensitivity without compromising structural simplicity.
2Measurement precision
If the reaction section is positioned lower than the IDT electrodes, then surface-acoustic-wave energy is concentrated on the reaction section, but the device structure becomes more complex
Solution Approach 1:
The patent segments the substrate surface into different levels: a first level for the IDT electrodes and a second, lower level for the reaction section. This segmentation is achieved by forming a groove in the substrate. The segmentation allows surface-acoustic-wave energy to be concentrated on the reaction section while maintaining clear functional separation between the IDT electrodes and the reaction section, thus improving detection sensitivity with minimal structural complexity.
3Measurement precision
If the reaction section is positioned lower than the IDT electrodes, then detection sensitivity is improved, but manufacturing process becomes more difficult
Solution Approach 1:
The patent employs preliminary action by forming the groove in the substrate before depositing the reaction section. This preliminary groove formation creates a pre-defined lower level structure that guides subsequent manufacturing steps. The groove can be formed using standard semiconductor fabrication techniques such as photolithography and etching, making the manufacturing process manageable despite the additional structural complexity required for energy concentration.
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 high-sensitivity detection of analyte liquid constituents by ensuring that the surface acoustic wave energy is effectively focused on the reaction section, improving measurement accuracy and reliability.
Implementation Method 1
measuring variation in a surface acoustic wave propagating through the reaction section
Implementation Method 2
a reaction section which undergoes reaction with a component contained in a sample of an analyte liquid, is disposed on a piezoelectric substrate
Data Source
Figure 1(a)~1(c)
Figure 2(a)~2(e)
Figure 3(a)~3(e)
AI summary
The invention relates to a sensor apparatus capable of measuring an analyte with excellent sensitivity. A sensor apparatus (100) includes an element substrate (10a); a detecting section (10b) disposed on an upper surface of the element substrate (10a), the detecting element including a reaction section (13) having an immobilization film (13a) to detect an analyte, a first IDT electrode (11) configured to generate an acoustic wave which propagates toward the reaction section (13), and a second IDT electrode (12) configured to receive the acoustic wave which has passed through the reaction section (13); and a protective film (28) which covers the first IDT electrode (11) and the second IDT electrode (12). The element substrate (10a) is configured so that a region where the reaction section (13) is located is at a lower level than a region where the first IDT electrode (11) is located and a region where the second IDT electrode (12) is located.