MEMS Vibration-Insulating Plate With Phononic Crystal Bandgap
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Solution Overview
Problem
Existing MEMS devices face challenges in effectively isolating from unwanted external vibrations, which affect their performance and stability, and current solutions are either inefficient or require tailored designs for each resonator, limiting their robustness and applicability.
Innovation Solution
A MEMS device incorporating a vibration-insulating plate with a planar periodic structure based on phononic crystals, which surrounds the resonating element and provides a 3D bandgap to attenuate external vibrations, using folded-beam springs to suspend mass elements and connect them to an outer frame, fully compatible with standard silicon industry manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If differential architectures are introduced to cancel external vibrations, then vibration compensation is improved, but electromechanical non-idealities cause unwanted output changes
Solution Approach 1:
A phononic crystal layer is introduced as an intermediary between the resonator and the substrate to block vibration propagation. This mediator absorbs and reflects external vibrations before they reach the resonator, avoiding the need for differential architectures that amplify noise due to electromechanical non-idealities.
Solution Approach 2:
The phononic crystal structure converts harmful external vibrations into benign localized vibrations within its bandgap frequency range. By designing the phononic crystal with specific geometric parameters, external vibrations are trapped and dissipated in the phononic layer itself, preventing them from affecting the resonator.
2Object-affected harmful factors
If resonant frequency is increased to exceed environmental excitation spectrum, then vibration isolation is improved, but device sensitivity decreases due to ultra-narrow gaps
Solution Approach 1:
Instead of increasing resonant frequency in the temporal dimension, the solution introduces a spatial dimension approach by adding a phononic crystal layer beneath the resonator. This layered structure creates a frequency-selective vibration barrier that isolates the resonator from environmental vibrations without requiring the resonator itself to operate at ultra-high frequencies.
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 effectively isolates MEMS devices from unwanted vibrations, enhancing their performance and robustness across a wide range of applications, while being compatible with standard manufacturing technologies and resistant to process variations and environmental conditions.
Implementation Method 1
The vibration-insulating plate comprises a planar periodic structure surrounding the at least one resonating element, said planar periodic structure comprising a plurality of adjacent unit cells, each unit cell comprising a respective movable mass element suspended by spring elements
Implementation Method 2
provides a two-dimensional phononic crystal around and/or below the resonating element... showing a 3D bandgap in the frequency range of interest
Implementation Method 3
each unit cell comprising a respective movable mass element suspended by spring elements. The spring elements comprise folded-beam springs
Data Source
Figure 1~2
Figure 3~6B
Figure 7A~9B
AI summary
The present invention relates to a MEMS device (100, 200, 400, 500, 600) comprising: at least one resonating element (101, 401, 501, 601) and a vibration-insulating plate (102, 402, 502, 602) centrally housing the at least one resonating element (101, 401, 501, 601). The vibration- insulating plate (102, 402, 502, 602) comprises a planar periodic structure (103, 403, 503, 603) surrounding the at least one resonating element (101, 401, 501, 601). The planar periodic structure (103, 403, 503, 603) comprises a plurality of adjacent unit cells (104, 404, 504, 604; 300), each unit cell (104, 404, 504, 604; 300) comprising a 10 respective movable mass element (301) suspended by spring elements (302).