Low-Temperature Vacuum Joint Formation for Hermetic Cavity Sealing
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Solution Overview
Problem
Existing methods for forming hermetically sealed cavities often require heating, which can damage sensitive components and involve the use of filler materials, leading to potential leaks and the release of harmful substances.
Innovation Solution
A method involving a vacuum chamber to create a preliminary joint between two pieces with sealing surfaces, followed by laser welding outside the chamber, using materials like glass, silicon, or ceramic to form a hermetic seal without heating and without filler materials, allowing for precise control of pressure and temperature to minimize stress and outgassing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heating is used to form hermetically sealed cavities, then the sealing process can be completed, but sensitive components may be damaged and harmful substances may be released
Solution Approach 1:
The patent replaces the thermal field (heating/cooling process) with a controlled pressure field. By applying vacuum pressure to remove gases from the cavity and then using positive pressure to force filler material into the sealing gap, the sealing process is achieved without thermal damage to components. This substitution of physical fields resolves the contradiction between achieving reliable seals and avoiding component damage.
Solution Approach 2:
The patent changes the working parameters from temperature-based control to pressure-based control. Instead of heating to melt filler material and then cooling to seal, the process uses vacuum pressure to evacuate gases and positive pressure to inject filler material. This parameter change eliminates thermal harm while maintaining sealing effectiveness.
2Reliability
If filler material is used to form hermetically sealed cavities, then the sealing process can be completed, but potential leaks and release of harmful substances may occur
Solution Approach 1:
The patent replaces thermal processing with mechanical pressure control. By using vacuum pressure to evacuate gases and positive pressure to force filler material into sealing gaps, the process achieves reliable seals without the thermal decomposition that causes harmful substance release. The filler material is injected in a controlled manner, preventing leaks.
Solution Approach 2:
The patent creates a controlled pressure environment that prevents harmful reactions. By evacuating gases from the cavity before sealing and controlling the injection of filler material under pressure, the process eliminates the presence of reactive gases that could lead to leaks or harmful substance release during and after sealing.
3Reliability
If high temperature heating is used for welding glass pieces, then hermetic sealing can be achieved, but the process complexity and risk of damage increase
Solution Approach 1:
The patent replaces the complex thermal processing system (heating furnaces, controlled cooling) with a simpler pressure control system. Vacuum pumps and pressure vessels are used to control the filling process, eliminating the need for high-temperature equipment and complex thermal management while achieving equivalent or superior sealing results.
Solution Approach 2:
The patent fundamentally changes the process parameter from temperature to pressure. Instead of controlling heating rates, peak temperatures, and cooling curves, the process controls vacuum pressure levels and positive pressure injection rates. This parameter change simplifies the equipment and process control while maintaining hermetic sealing quality.
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 approach enables the formation of hermetically sealed structures with reduced risk of component damage, lower temperatures, and minimized release of harmful substances, improving the reliability and efficiency of the sealing process.
Implementation Method 1
changing the internal pressure (p2) of the chamber (200) so as to cause a flow (F1) of a gas (GAS1) from the open cavity (OCA1)
Implementation Method 2
forming a welded seam (J1) by focusing a laser beam (B1) to the interface (IF1)
Data Source
AI summary
An article is produced by welding a first piece to a second piece by a laser beam. The first piece includes an open cavity and a first sealing surface. The second piece has a second sealing surface. The first piece and second piece are inside chamber with a controllable internal pressure that is changed to cause a flow of a gas from the open cavity. The open cavity is closed by moving at least one of the pieces. The first sealing surface forms a partially gas tight preliminary joint with the second sealing surface. The first piece and the second piece define an interface. The chamber is opened after the preliminary joint has been formed. A welded seam is formed by focusing a laser beam to the interface after the chamber is opened. The first sealing surface and the second sealing surface are substantially planar.