Stepped SAW Sensor Layout for Higher Analyte Detection 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 insufficient concentration of surface-acoustic-wave energy on the reaction section.
Innovation Solution
A sensor apparatus with a configuration where the reaction section is positioned at a lower level than the IDT electrodes, allowing for concentrated surface acoustic wave energy and improved detection sensitivity, featuring a detecting section with a reaction section, first and second IDT electrodes, and a protective film, and a protective film covering the electrodes.
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 invention transitions from a two-dimensional planar arrangement to a three-dimensional stepped structure by forming a recess in the substrate. The reaction section is positioned in a recessed region at a lower level than the IDT electrodes, creating a vertical dimension that enables surface-acoustic-wave energy concentration through geometric confinement, thereby resolving the contradiction between structural simplicity and detection sensitivity.
Solution Approach 2:
The invention applies local quality by creating a specific geometric feature (recess) only in the region where the reaction section is located. This localized structural modification concentrates surface-acoustic-wave energy precisely where needed for detection, while the rest of the substrate maintains its original simple structure, thus balancing detection sensitivity improvement with overall device complexity.
2Measurement precision
If the reaction section is positioned at a lower level than the IDT electrodes, then surface-acoustic-wave energy is concentrated on the reaction section improving detection sensitivity, but the manufacturing process becomes more complex
Solution Approach 1:
The invention changes the geometric parameter of the substrate by introducing a recess with specific depth and dimensions. This parameter modification creates the necessary three-dimensional structure for energy concentration while maintaining compatibility with standard semiconductor fabrication techniques, thus achieving improved detection sensitivity without excessive manufacturing complexity.
3Measurement precision
If conventional sensor apparatus is used with flat substrate, then manufacturing is simple, but surface-acoustic-wave energy dispersion reduces measurement precision
Solution Approach 1:
The invention introduces a vertical dimension by forming a recess in the substrate, transforming the flat two-dimensional structure into a three-dimensional stepped structure. This dimensional change enables surface-acoustic-wave energy to be confined and concentrated in the recessed region where the reaction section is located, directly improving measurement precision while adding only minimal structural complexity.
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 concentrating surface acoustic wave energy on the immobilization film, enhancing the detection reliability and accuracy.
Implementation Method 1
a first IDT electrode configured to generate an acoustic wave which propagates toward the reaction section, and a second IDT electrode configured to receive the acoustic wave which has passed through the reaction section
Implementation Method 2
the upper surface of the element substrate is configured so that a region where the reaction section is located is at a lower level than a region where the first IDT electrode is located and a region where the second IDT electrode is located. Therefore, in the reaction section, energy of the surface acoustic wave propagating between the first IDT electrode and the second IDT electrode is readily concentrated on the immobilization film
Data Source
AI summary
A sensor apparatus capable of measuring an analyte with excellent sensitivity is provided. A sensor apparatus includes an element substrate; a detecting section disposed on an upper surface of the element substrate, the detecting element including a reaction section having an immobilization film to detect an analyte, a first IDT electrode configured to generate an acoustic wave which propagates toward the reaction section, and a second IDT electrode configured to receive the acoustic wave which has passed through the reaction section; and a protective film which covers the first IDT electrode and the second IDT electrode. The element substrate is configured so that a region where the reaction section is located is at a lower level than a region where the first IDT electrode is located and a region where the second IDT electrode is located.