Quartz Crystal Resonator Vibration Damping via Outer Electrode
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Solution Overview
Problem
Conventional quartz crystal resonator units suffer from unwanted vibration due to excitation vibration leaking out and propagating through sealing materials, which deteriorates the quality of the resonator units.
Innovation Solution
A quartz crystal resonator unit design featuring a quartz crystal blank with excitation electrodes, a frame surrounding the blank, and coupling members, where the lid and base members are made of quartz crystal or glass, and outer electrodes are formed on the end surfaces of these components with a lower machinery quality factor than the frame, effectively attenuating and dispersing reflected waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional sealing structure with lid and base units bonded to the piezoelectric substrate is used, then the resonator unit is hermetically sealed, but excitation vibration leaks through the sealing material and reflects at the end face of substrates, deteriorating the characteristics of the piezoelectric substrate
Solution Approach 1:
The patent introduces an intermediate structure (sealing protrusions and sealing grooves with sealing material) between the lid unit and base unit to achieve hermetic sealing while controlling vibration propagation. The sealing material acts as a mediator that both seals the cavity and manages the vibration transmission path.
Solution Approach 2:
The patent converts the potentially harmful reflected vibrations into beneficial effects by designing the sealing structure to control and dissipate vibration energy. The sealing protrusions and grooves create a path that allows controlled vibration transmission while preventing harmful reflections from reaching the piezoelectric substrate.
2Reliability
If the lid unit and base unit are individually bonded by sealing material to the piezoelectric substrate, then the resonator is sealed, but vibration energy propagates through the sealing material to the substrates and reflects, damaging the quality of the resonator unit
Solution Approach 1:
The patent segments the sealing structure into multiple components: sealing protrusions on the base unit, sealing grooves on the lid unit, and sealing material filling the grooves. This segmentation allows independent optimization of each component's function while achieving overall sealing performance and vibration control.
Solution Approach 2:
The patent applies different properties to different parts of the sealing structure. The sealing material has both sealing properties (to close the cavity) and vibration damping properties (to control vibration propagation). The sealing protrusions and grooves are designed with specific geometries to control the vibration path locally.
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 reduces the influence of reflected waves, thereby improving the quality of the quartz crystal resonator unit by consuming and attenuating vibration energy, thus minimizing unwanted vibration and enhancing performance.
Implementation Method 1
part of vibration leaking out of the quartz crystal resonator propagates through the end portions of the lid member and the base member to the outer electrode, in which vibration energy is consumed
Implementation Method 2
waves attenuated by the outer electrode are reflected, it is possible to relieve or disperse the influence of the reflected waves
Data Source
AI summary
A quartz crystal resonator unit including a quartz crystal resonator having a quartz crystal blank, a frame surrounding an outer periphery of the quartz crystal blank, and coupling members connecting the frame to the quartz crystal blank. Moreover, a lid member and a base member are attached to the frame and seal the resonator. One or more outer electrodes is formed over end surfaces of the frame, the lid member, and the base member on a side where the coupling members are coupled. The one or more outer electrodes has a machinery quality factor smaller than that of the frame.