AT-Cut Crystal Resonator Structure for Robust Electrode Mounting
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Solution Overview
Problem
Existing crystal vibrators have costly packaging due to the use of metal or glass-made lid members with ceramic bases, and electrodes are prone to breakage due to exposure and sharp corners during wet etching.
Innovation Solution
A crystal vibration device with an AT-cut crystal vibration plate featuring first and second driving electrodes, mounting terminals, and sealing members that cover the electrodes, along with castellations formed by depositing electrodes on cutouts, which reduces the risk of electrode breakage and eliminates the need for expensive bases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal or glass-made lid member is joined to a ceramic base to seal the crystal vibration piece, then the sealing reliability is improved, but the manufacturing cost increases
Solution Approach 1:
The patent replaces expensive metal or glass lid members with a resin sealing member that is cheaper and sufficient for the application requirements. The resin member provides adequate sealing without the high cost of traditional metal or glass components, directly addressing the cost reduction goal while maintaining functional sealing reliability.
Solution Approach 2:
The patent changes the material parameter of the sealing member from metal/glass to resin, which has different mechanical and chemical properties. This material substitution allows for cost reduction while the resin's flexibility and bonding characteristics provide sufficient sealing performance for the crystal vibration device.
2Ease of operation
If electrodes are routed in right-angled or sharp-angled corners of the crystal plate, then the electrical connection is established, but the electrode thickness is reduced and breakage risk increases
Solution Approach 1:
The patent replaces sharp-angled corners with rounded corners in the crystal plate design. This curvature modification eliminates the stress concentration points that cause electrode thinning and breakage, while still allowing proper electrode routing and electrical connection. The rounded corners distribute stress more evenly, maintaining electrode strength.
Solution Approach 2:
The patent proactively designs rounded corners to prevent electrode breakage before it occurs. By anticipating the stress concentration problem at sharp corners, the design incorporates rounded geometry that cushions and distributes mechanical stress, preventing electrode damage during handling and operation.
3Shape
If the crystal plate is processed by wet etching to form its outer shape, then the desired geometry is achieved, but the lateral surfaces have variable shapes with right-angled or sharp-angled corners
Solution Approach 1:
The patent intentionally introduces rounded corners into the crystal plate design to compensate for the variable shapes produced by wet etching. This design feature transforms the manufacturing variability into a controlled geometric characteristic, ensuring that all crystal plates have uniform rounded corners regardless of etching variations, thereby improving overall shape consistency.
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 solution reduces the risk of electrode breakage, improves the reliability of electrical connections, and eliminates the need for costly bases, resulting in a more cost-effective and reliable crystal vibration device.
Implementation Method 1
an AT-cut crystal vibration plate having a first driving electrode and a second driving electrode
Implementation Method 2
first and second sealing members that are respectively joined to the main surfaces on both sides of the AT-cut crystal vibration plate in a manner that the first and second driving electrodes of the AT-cut crystal vibration plate are covered with the first and second sealing members
Data Source
AI summary
An AT-cut crystal vibration plate has, at its both ends, first and second castellations that interconnect first mounting terminals and also interconnect second mounting terminals formed on main surfaces on both sides of this plate. The first and second castellations respectively have first and second cutouts, and these cutouts each have an end surface extending along Z′ axis of crystal and located on a −X-axis side. The end surfaces each include a first inclined face inclined in a manner that protrudes from one of the main surfaces toward the −X-axis side, and a second inclined face inclined in a manner that protrudes from the other main surface toward the −X-axis side. The angle made by the first inclined face and the second inclined face is an obtuse angle.