Quartz Crystal Resonator Package Sealing for Lid Position Stability
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Solution Overview
Problem
Existing quartz crystal resonator units face challenges in achieving desirable hermeticity and joining strength due to low accuracy in the positioning of lid and base members, which can impair the frequency stability and durability of the resonator.
Innovation Solution
A quartz crystal resonator unit design featuring a base member with protruding portions made of a second sintered material with a smaller sintering shrinkage ratio than the base body, which are electrically connected and used to enhance the joining strength by having the joining member cover these protrusions and contact with the lid member's side wall, thereby restraining movement and improving hermeticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If protrusions are formed on the base member to improve positioning accuracy, then joining strength is improved, but hermeticity may be impaired if positioning accuracy is low
Solution Approach 1:
A joining member is introduced as an intermediary component between the base member and lid member. This joining member covers the protrusions and provides a sealing function, preventing direct contact between the protrusions and the inner space, thus maintaining hermeticity while still providing positioning and joining strength.
Solution Approach 2:
The base member is designed with different properties in different regions: protruding portions are formed at specific locations to provide positioning and joining strength, while the sealing portion is designed with smooth surfaces and appropriate thickness to ensure hermeticity. This local differentiation allows both positioning accuracy and hermeticity to be achieved.
2Ease of manufacture
If the sealing portion is made thin to reduce material usage, then manufacturing cost is reduced, but joining strength and hermeticity are impaired
Solution Approach 1:
The sealing portion is designed with an optimized thickness that balances material usage with structural requirements. The thickness is sufficient to provide joining strength and hermeticity while minimizing material consumption. The sealing portion is located at a specific distance from the outer peripheral edge, allowing thin-section construction without compromising strength.
Solution Approach 2:
The joining member acts as a mediator that reinforces the joining between the base member and lid member. This allows the sealing portion to be thinner since the joining strength is supplemented by the joining member that covers the protrusions and provides additional bonding area.
3Manufacturing precision
If protruding portions are formed to enhance positioning, then joining strength is improved, but hermeticity is impaired if positioning accuracy is insufficient
Solution Approach 1:
The joining member serves as a mediator that compensates for positioning inaccuracies. It covers the protrusions and provides a continuous sealing path, ensuring hermeticity even when the positioning of protrusions is not perfectly accurate. This intermediary layer isolates the sealing function from the positioning function.
Solution Approach 2:
The design anticipates potential positioning inaccuracies by incorporating a sealing portion with sufficient thickness and a joining member that covers the protrusions. This beforehand cushioning ensures that even if positioning is not perfect, the hermeticity is maintained through the redundant sealing path provided by the joining member.
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 significantly enhances the joining strength and hermeticity of the quartz crystal resonator unit, ensuring improved frequency stability and durability by effectively restraining the lid member's displacement and maintaining a vacuum state within the resonator.
Implementation Method 1
a base member including a surface and two protruding portions on the surface... made of a second sintered material whose sintering shrinkage ratio is smaller than a sintering shrinkage ratio of the base body
Data Source
AI summary
A quartz crystal resonator unit includes a quartz crystal resonator that includes a quartz crystal blank. A pair of excitation electrodes are disposed on opposed main surfaces of the quartz crystal blank so as to face each other. A pair of connection electrodes are electrically connected to respective ones of the pair of excitation electrodes. A base member has a surface on which the quartz crystal resonator is mounted. A lid member is joined to the surface of the base member via a joining member. The quartz crystal resonator is accommodated in an inner space defined by the lid member and the base member on the surface of the base member. Parts of the joining member that cover protruding portions are in contact with a side wall of the lid member so as to restrain movement of the lid member when seen in a plan view in a direction normal to the surface of the base member.