Nested Cavity Microdevice for Vibration Isolation and Pressure Control
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Solution Overview
Problem
Existing micro-devices, such as MEMS and NEMS, face challenges in achieving optimal vibration isolation and different operating pressures within multiple suspension stages, which are not adequately addressed by current encapsulation methods, especially for sensors requiring varied pressures and isolation from external vibrations.
Innovation Solution
A micro-device design featuring nested cavities with walls formed by fixed and mobile elements, allowing for independent atmospheres and pressures within each cavity, and a triple suspension stage for enhanced insulation, enabling effective vibration filtration and different operating conditions for various components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single cavity encapsulation method is used for microdevices with multiple suspension stages, then the device structure is simple, but different operating pressures cannot be achieved for different suspension stages
Solution Approach 1:
The patent implements nested cavities where a first cavity contains a second cavity, and the second cavity contains a third cavity. Each cavity can be independently sealed and pressurized, allowing different suspension stages to operate at different pressures. The nested structure enables multiple independent atmospheres within a compact form factor, resolving the contradiction between adaptability and complexity.
2Object-affected harmful factors
If conventional WLP packaging is used, then manufacturing cost is low, but vibration isolation performance is insufficient for sensitive sensors
Solution Approach 1:
The nested cavity structure creates multiple isolation barriers between external vibrations and sensitive sensor elements. Each cavity layer provides additional vibration damping and isolation, significantly improving protection against harmful vibrations while maintaining a compact integrated structure suitable for sensor applications.
3Adaptability or versatility
If multiple separate encapsulation processes are used for different suspension stages, then different operating pressures can be achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent forms all cavity structures and sealing elements during the initial microdevice fabrication process, before final assembly. This preliminary structuring allows subsequent independent pressurization of each cavity without requiring complex post-assembly operations, simplifying manufacturing while enabling different operating pressures for each suspension stage.
Data Source
Figure 1A~1B
Figure 2A~2B
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AI summary
Micro-device (100) comprising: - a substrate, - a fixed element (102) attached to the substrate, - a first mobile element (104) suspended from the fixed element by first retaining elements, and capable of moving relative to the fixed element, - a second mobile element (108) suspended from the first mobile element by second retaining elements, and capable of moving relative to the first mobile element and the fixed element, - a first cavity (116) of which at least a part of the walls is formed by the fixed element and in which the first mobile element is encapsulated, - a second cavity (120) disposed within the first cavity, of which at least a part of the walls is formed by the first mobile element, in which the second mobile element is encapsulated and which is isolated from the first cavity.