Crystal resonator
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Solution Overview
Problem
Existing crystal resonators vibrating in a thickness-shear mode face challenges in achieving identical displacement distributions at the edges of excitation electrodes on both surfaces, leading to susceptibility to unwanted vibrations and energy loss.
Innovation Solution
The crystal resonator design involves positioning excitation electrodes on both surfaces with a specific displacement relationship, where the first electrode is moved along the X-axis and Z-axis, and the second electrode is positioned accordingly to match the displacement distribution, with optimal angles and ellipse ratios determined through finite element method simulations to achieve identical edge displacements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If excitation electrodes are disposed on both surfaces of a crystal element with conventional positioning, then the crystal resonator can be manufactured with standard structures, but unwanted vibrations and energy loss occur due to non-identical displacement distributions at the electrode edges
Solution Approach 1:
The patent applies asymmetry by intentionally creating a non-symmetric displacement relationship between excitation electrodes on opposite surfaces. Specifically, the electrodes are positioned such that their displacement distributions at the edges are non-identical, which asymmetrically distributes the vibration energy to suppress unwanted vibrations and reduce energy loss at the electrode boundaries.
Solution Approach 2:
The patent applies local quality by optimizing the displacement distribution specifically at the edge regions of the excitation electrodes. By controlling the local displacement characteristics at the electrode edges rather than uniformly across the entire electrode surface, the invention targets the specific location where unwanted vibrations occur, thereby improving vibration stability without requiring complete redesign of the entire electrode structure.
2Loss of energy
If excitation electrodes are positioned to achieve identical displacement distributions at both surfaces, then unwanted vibrations are reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by optimizing specific geometric parameters of the excitation electrodes, including their positions, sizes, and displacement distributions. By carefully adjusting these parameters to achieve identical displacement distributions at the edges of electrodes on both surfaces, the invention reduces vibration energy loss while establishing concrete manufacturing specifications that balance precision requirements with practical manufacturability.
3Reliability
If excitation electrodes are displaced relative to each other to control frequency-temperature characteristics, then frequency stability is improved, but the displacement distribution matching between surfaces becomes difficult to achieve
Solution Approach 1:
The patent applies parameter changes by systematically optimizing multiple electrode parameters simultaneously - including relative displacement distances, electrode sizes, and displacement distributions. This multi-parameter optimization approach enables the achievement of identical displacement distributions at electrode edges while maintaining the frequency-temperature characteristics control, thereby resolving the conflict between frequency stability and displacement matching precision.
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 design results in improved displacement matching at the edges of the excitation electrodes, reducing unnecessary vibrations and energy loss, thereby enhancing the properties of the crystal resonator.
Implementation Method 1
a crystal resonator vibrating in a thickness-shear mode... excitation electrodes being disposed on a front surface and a back surface of a crystal element
Data Source
AI summary
A crystal resonator vibrates in a thickness-shear mode. The crystal resonator includes excitation electrodes being disposed on a front surface and a back surface of a crystal element. The excitation electrodes are disposed on the crystal element to have a positional relationship, where a displacement distribution at an edge of the excitation electrode on the front surface is identical to a displacement distribution at an edge of the excitation electrode on the back surface.