Quartz Crystal Resonator Sealing Layout to Suppress Unwanted Resonance
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Solution Overview
Problem
The challenge is to reduce the size of quartz crystal resonator units while maintaining high resonance characteristics, as existing methods that eliminate through-holes to achieve smaller sizes often result in unwanted resonance due to conductive sealing members opposing each other, degrading the resonance performance.
Innovation Solution
A quartz crystal resonator unit design featuring a quartz crystal substrate with excitation electrodes and conductive sealing members on opposing surfaces, where the sealing members are positioned to minimize overlap and reduce unwanted resonance, eliminating the need for via-electrodes and allowing for a compact structure without compromising resonance quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conductive sealing members are positioned to eliminate through-holes and reduce size, then the device size is reduced, but unwanted resonance occurs due to overlapping conductive sealing members degrading resonance characteristics
Solution Approach 1:
The patent applies asymmetry by making the first and second conductive sealing members have different patterns of overlap with the quartz crystal substrate. Specifically, the first conductive sealing member has a first overlap region while the second conductive sealing member has a second overlap region, creating an asymmetric configuration that prevents direct opposition between the sealing members. This asymmetric arrangement eliminates unwanted resonance while maintaining the compact structure without through-holes.
Solution Approach 2:
The patent segments the conductive sealing members into distinct regions with different overlap characteristics. The first conductive sealing member is segmented to have a first overlap region with the substrate, while the second conductive sealing member is segmented to have a second overlap region. This segmentation allows each sealing member to be optimally positioned to avoid direct opposition, thereby preventing unwanted resonance while achieving size reduction.
2Reliability
If via-electrodes are used to connect electrodes through the substrate, then reliable electrical connection is achieved, but the device size increases due to required through-hole regions
Solution Approach 1:
The patent extracts and eliminates the via-electrode structure from the design. Instead of using through-holes with via-electrodes to achieve electrical connection, the invention uses surface-level conductive sealing members that extend to overlap regions on the substrate. This extraction of the via-electrode concept allows reliable electrical connection to be achieved through the conductive sealing members alone, eliminating the need for through-holes and reducing device size.
Solution Approach 2:
The patent transitions from a three-dimensional via-electrode structure (passing through the substrate thickness) to a two-dimensional surface-level conductive sealing member configuration. By moving the electrical connection function to the surface level with overlap regions on the substrate, the invention eliminates the need for vertical through-holes, thereby reducing device size while maintaining electrical connection reliability.
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 achieves a reduced size for the quartz crystal resonator unit while minimizing the degradation of resonance characteristics, maintaining high frequency accuracy and sensitivity to external loads, suitable for both timing devices and load sensors.
Implementation Method 1
a quartz crystal resonator unit uses a synthetic quartz crystal in a piezoelectric member
Implementation Method 2
maintaining high resonance characteristics
Data Source
AI summary
A quartz crystal resonator unit includes a quartz crystal substrate, first and second excitation electrodes, first and second conductive sealing members, and first and second exterior members. The first excitation electrode is disposed on a first main surface of the substrate with the first conductive sealing member surrounding the first excitation electrode. Similarly, the second excitation electrode is disposed on a second main surface of the substrate with the second conductive sealing surrounding the second excitation electrode. The first and second exterior members are bonded to the quartz crystal substrate with the first and second conductive sealing member respectively interposed therebetween and to cover the first and excitation electrodes, respectively. In a plan view of the first main surface of the substrate, at least part of the first conductive sealing member is located outward of the second conductive sealing member.