SC-Cut Quartz Resonator Electrode Layout for Vibration Suppression
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Solution Overview
Problem
Existing resonator elements using AT cut quartz crystal substrates do not effectively suppress unnecessary vibrations, particularly in SC cut quartz crystal substrates, which affect sensitivity and stability.
Innovation Solution
The resonator element employs an SC cut quartz crystal plate with specifically designed excitation electrodes and coupling electrodes, featuring chamfered corners and dimensions that satisfy certain width ratios, to suppress unnecessary vibrations and improve vibration characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AT cut quartz crystal substrate is used with arc-shaped edges, then unnecessary vibrations are suppressed, but the method does not work for SC cut quartz crystal substrates
Solution Approach 1:
The patent applies different edge configurations to different parts of the substrate. Specifically, the first and second edges have different shapes (one arc-shaped, one straight or differently angled) to suppress different types of unnecessary vibrations. This local differentiation allows the single substrate to achieve both AT-cut and SC-cut vibration suppression characteristics.
Solution Approach 2:
The substrate edges are segmented into different types (first edge, second edge, third edge, fourth edge) with different geometric configurations. This segmentation allows each edge to address specific vibration modes independently, making the solution adaptable to different crystal cut requirements.
2Ease of manufacture
If rectangular excitation electrodes are used without chamfered corners, then manufacturing is simpler, but equivalent series resistance increases and oscillation characteristics deteriorate
Solution Approach 1:
Chamfered corners are added to the rectangular excitation electrodes, creating asymmetric corner geometry. This asymmetry is specifically designed to reduce equivalent series resistance and improve oscillation characteristics while maintaining the overall rectangular shape for ease of manufacturing.
3Reliability
If chamfered portions are added to excitation electrodes, then unnecessary sub-vibrations are suppressed, but electrode complexity increases
Solution Approach 1:
The chamfered portions are defined by specific width parameters (e1, e2, e3, e4) that can be optimized to suppress different vibration modes. By adjusting these parameters, the electrode geometry achieves vibration suppression without excessive complexity, balancing performance and manufacturability.
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 design effectively suppresses unnecessary sub-vibrations, stabilizes main vibrations, and enhances oscillation characteristics by reducing equivalent series resistance and support stress, resulting in improved reliability and performance.
Implementation Method 1
a first excitation electrode disposed on the first surface
Data Source
AI summary
A resonator element includes a substrate made of an SC cut quartz crystal plate, a first excitation electrode disposed on a first surface, and a first coupling electrode electrically coupled to the excitation electrode and provided at one end portion in an X′-axis direction of the substrate, in which the first excitation electrode includes chamfered portions at positions of four corners in a rectangle, and when a width in a Z′-axis direction of a chamfered portion located on a +Z′ side of a first short side is defined as e1, a width in the Z′-axis direction of a chamfered portion located at a −Z′ side of the first short side is defined as e2, a width in the Z′-axis direction of a chamfered portion located on the −Z′ side of a second short side is defined as e3, and a width in the Z′-axis direction of a chamfered portion located on the +Z′ side of the second short side is defined as e4, e1, e2, e3, and e4 satisfy the following expressions (1) to (4):e2<e1(1)e4<e3(2)e2<e3(3)e4<e 1.(4)