AT-Cut Quartz Resonator Electrode Layout to Prevent Peeling
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Solution Overview
Problem
Existing resonator technologies face issues with extraction electrodes peeling off and unwanted defects during cutting, which affect the vibration characteristics of resonator pieces due to snap-off portions being on the same side surfaces.
Innovation Solution
The resonator element design features AT-cut quartz crystal substrates with excitation and extraction electrodes positioned on different side surfaces, including a first side surface and intersecting second and third side surfaces, with holders disposed at these surfaces to facilitate stable cutting and minimize defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If extraction electrodes are routed along the same side surfaces as snap-off portions, then the resonator pieces can be cut into individual elements, but the extraction electrodes may peel off during cutting
Solution Approach 1:
The patent relocates the extraction electrodes from the same side surface as the snap-off portions to adjacent side surfaces. This spatial reconfiguration in a different dimension (from co-planar to adjacent surfaces) allows the cutting operation to proceed without the electrodes being in the path of the cut, thereby preventing peeling while maintaining cutting efficiency
Solution Approach 2:
The patent introduces a support frame structure that serves as an intermediary carrier for the extraction electrodes during the cutting process. The electrodes are routed along the support frame rather than directly along the snap-off portions, providing mechanical support and isolation that prevents peeling during separation
2Ease of manufacture
If snap-off portions are present in the direction of thickness shear vibration, then resonator pieces can be separated, but burrs and defects affect vibration characteristics
Solution Approach 1:
The patent applies local quality by creating a fracture surface with specific characteristics (smooth, burr-free) at the snap-off portions through controlled breaking. The fracture surface is engineered to have different properties than the bulk material, ensuring clean separation that does not compromise the vibration characteristics of the resonator pieces
Solution Approach 2:
The patent converts the potentially harmful effect of cutting-induced burrs and defects into a benefit by using controlled fracture mechanics. Instead of mechanical cutting that creates burrs, the snap-off portions are designed to break cleanly along predetermined fracture lines, transforming the separation process from harmful to beneficial for vibration characteristics
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 prevents peeling and burrs during cutting, maintaining satisfactory vibration characteristics of the resonator elements by locating extraction electrodes on surfaces separate from fracture surfaces.
Implementation Method 1
an AT-cut quartz crystal substrate having a first surface that is a front surface and a second surface that is a rear surface with respect to the front surface
Data Source
AI summary
A resonator element includes an AT-cut quartz crystal substrate having a first surface that is a front surface and a second surface that is a rear surface with respect to the front surface, the two surfaces extending along the axes X and Z′ of a quartz crystal, and further having side surfaces that link the first and second surfaces to each other, a first excitation electrode disposed at the first surface, a first extraction electrode disposed at the first surface and coupled to the first excitation electrode, a second excitation electrode disposed at the second surface, and a second extraction electrode disposed at the second surface and coupled to the second excitation electrode. The side surfaces include a first side surface located at one side of the direction of the axis X, and second and third side surfaces that intersect with the first side surface. At least one of the first and second extraction electrodes is disposed at and extends along the first side surface. At least one of the second and third side surfaces has a fracture surface.