Piezoelectric Bulk Wave Resonator Thickness Tuning for High Q
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Solution Overview
Problem
Existing acoustic wave devices using piezoelectric layers face challenges in miniaturization, leading to a decrease in Q value and difficulty in adjusting resonant frequency.
Innovation Solution
The acoustic wave device employs a bulk wave of a thickness slip first-order mode with first and second resonators, where the thickness of each resonator differs, and the electrodes are positioned to intersect orthogonally, allowing for increased Q value and resonant frequency adjustment even in a miniaturized design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the number of electrode fingers is reduced to miniaturize the device, then the device size is reduced, but the Q value is lowered
Solution Approach 1:
The patent changes the resonator thickness parameter to resolve the contradiction between miniaturization and Q value maintenance. By making the first resonator thinner than the second resonator, the device achieves compact size while the specific thickness configuration maintains the Q value through optimized acoustic wave resonance characteristics.
Solution Approach 2:
The patent introduces thickness dimension variation between resonators to solve the size-Q value contradiction. While planar dimensions are reduced for miniaturization, the thickness dimension is differentiated (first resonator thinner than second resonator) to maintain acoustic wave resonance quality and Q value through three-dimensional structural optimization.
2Volume of moving object
If the number of electrode fingers is reduced to miniaturize the device, then the device size is reduced, but it becomes difficult to adjust the resonant frequency
Solution Approach 1:
The patent uses thickness parameter variation of resonators to enable resonant frequency adjustment in miniaturized devices. By configuring the first resonator with a smaller thickness than the second resonator, the device achieves both compact size and frequency tunability through the relationship between resonator thickness and acoustic wave resonance frequency.
Solution Approach 2:
The patent employs thickness dimension differentiation to provide frequency adjustment capability in a miniaturized device. The varying thicknesses of first and second resonators create different acoustic wave resonance conditions, enabling frequency tuning without increasing planar device dimensions.
3Volume of moving object
If the resonator thickness is reduced for miniaturization, then the device size is reduced, but the resonant frequency control becomes difficult
Solution Approach 1:
The patent changes the thickness parameter of resonators to achieve both miniaturization and precise resonant frequency control. The first resonator is configured with a smaller thickness than the second resonator, and this specific thickness relationship enables accurate frequency control through optimized acoustic wave resonance in the miniaturized structure.
Solution Approach 2:
The patent uses thickness dimension variation to solve the contradiction between miniaturization and frequency control precision. By differentiating resonator thicknesses in the vertical dimension while reducing planar dimensions, the device achieves compact size with maintained or enhanced frequency control through three-dimensional acoustic wave resonance optimization.
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 enhances the Q value and enables precise frequency tuning while maintaining device compactness, addressing the limitations of miniaturization in existing technologies.
Implementation Method 1
acoustic wave devices including piezoelectric layers... piezoelectric layer... when a voltage is applied between a plurality of electrode fingers connected to one potential of the IDT electrode and a plurality of electrode fingers connected to the other potential thereof, a Lamb wave is excited
Data Source
AI summary
An acoustic wave device includes a piezoelectric layer and first and second electrodes facing each other in a direction crossing a thickness direction of the piezoelectric layer. The acoustic wave device utilizes a bulk wave of a thickness slip first-order mode. The acoustic wave device includes first and second resonators. Each of the first and second resonators includes the first and second electrodes, and a setting portion including a setup region where the first and second electrodes are provided in the piezoelectric layer. The thickness of each of the first and second resonators excludes the thickness of the first and second electrodes included in the resonator. The thickness of the first resonator is different from the thickness of the second resonator.