Quartz Resonator Thickness Control for Low CI at High Frequency
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Solution Overview
Problem
Existing piezoelectric resonator elements face challenges in achieving high frequencies while maintaining a low CI value, which is essential for high-speed and large-capacity communication devices, as the CI value tends to increase with higher frequencies.
Innovation Solution
A resonator element with a quartz crystal substrate having a resonator portion and a support portion of varying thickness, along with specific electrode configurations, is designed to maintain a relationship between plate thickness variation and oscillation frequency to achieve a low CI value at high frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the oscillation frequency is increased to meet high-speed communication requirements, then the communication speed and capacity are improved, but the CI value increases which degrades the resonator performance
Solution Approach 1:
The support portion is designed with a thickness that is locally greater than the resonator portion, creating a thickness difference that provides mechanical support and stabilizes the resonator plate. This local thickening in the support portion reduces plate thickness variation without affecting the resonator region's oscillation characteristics, thereby maintaining low CI values even at high frequencies
Solution Approach 2:
The invention addresses the two-dimensional trade-off between frequency and CI value by introducing a third dimension - the thickness dimension. By varying the thickness in the support portion (making it thicker than the resonator portion), the patent creates a vertical dimension for control, allowing high-frequency operation with low CI values through thickness-based mechanical support rather than area-based design
2Volume of moving object
If the resonator area is reduced to miniaturize the device, then the device size is decreased, but the mechanical support and stability become insufficient leading to increased plate thickness variation
Solution Approach 1:
Rather than uniformly increasing the entire resonator structure size, the invention applies local quality by making only the support portion thicker than the resonator portion. This localized thickening provides the necessary mechanical support and stability to maintain plate thickness uniformity while keeping the overall device size compact and the resonator area small
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 resonator element achieves a low CI value even at high frequencies, ensuring the required performance for high-speed and large-capacity communication devices.
Implementation Method 1
a resonator element including a quartz crystal substrate (10)
Data Source
AI summary
A resonator element includes: a quartz crystal substrate having a resonator portion including a resonator region and a support portion having a thickness larger than a thickness of the resonator portion; and an excitation electrode disposed in the resonator region, in which when a plate thickness variation in the resonator region of the quartz crystal substrate is set to y [nm], and an oscillation frequency is set to x [MHz], y≤329.8 exp (−x/76.7)+4.0.