MEMS Inertial Sensor Vibration Testing and Damping
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Solution Overview
Problem
MEMS devices with inertial sensors face unreliable data issues due to vibrations, especially when the vibration frequency is close to the resonance frequency, and existing damping structures lack effective measurement methods for evaluating their performance.
Innovation Solution
A method involving a testing apparatus that applies vibrations to MEMS devices while moving them according to a predefined pattern, allowing for the evaluation of inertial sensor output data and calculation of frequency response curves to assess the accuracy and damping performance of the sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a damping structure is added to the MEMS device, then vibration attenuation performance is improved, but device volume and complexity increase
Solution Approach 1:
The damping structure is integrated within the existing MEMS device packaging volume by utilizing the space between the inertial sensor and the packaging cavity wall. The damping material is positioned in the gaps and voids of the MEMS structure, effectively using available space without requiring additional external volume.
Solution Approach 2:
The damping structure employs thin film damping materials that can be deposited as coatings on existing MEMS surfaces. This approach provides effective vibration attenuation while adding minimal volume, as the damping layer is applied as a thin film rather than requiring bulky separate damping components.
2Device complexity
If digital filters or sensor fusion algorithms are used to counter vibration effects, then device structure remains simple, but reliability under vibration deteriorates
Solution Approach 1:
The damping structure is implemented as a physical cushioning element that attenuates vibrations before they can significantly affect the inertial sensor. By placing damping material in the packaging cavity and on sensor surfaces, the system provides mechanical vibration reduction in advance, preventing resonance issues before they occur rather than attempting to correct them through software algorithms.
3Measurement precision
If the vibration frequency is close to the resonance frequency of the inertial sensor, then the sensor is highly sensitive to vibration, but data reliability deteriorates
Solution Approach 1:
The damping structure is designed to specifically target and attenuate vibrations at frequencies that would otherwise cause resonance in the inertial sensor. By converting the harmful resonance effect into a controlled damping effect, the system maintains sensor sensitivity while preventing the harmful amplification that occurs at resonant 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
This method enables the evaluation of MEMS devices' reliability under vibration conditions, ensuring they provide accurate data and effective damping, suitable for mass production without additional manufacturing steps, and can be performed on encapsulated devices.
Implementation Method 1
applying a vibration to the MEMS device by the vibration source
Implementation Method 2
when the frequency of the disturbance is close to the resonance frequency of the inertial sensor
Implementation Method 3
a MEMS device comprising a damping structure has been developed... It provides a fast attenuation of a vibration applied to a MEMS device
Data Source
AI summary
A method for measuring a behavior of a MEMS device is disclosed. In an embodiment a method includes mounting the MEMS device to a testing apparatus that comprises a vibration source, wherein the MEMS device comprises a 6-axis or 9-axis inertial sensor, applying a vibration to the MEMS device by the vibration source and simultaneously moving the testing apparatus according to a predefined movement pattern, reading output data provided by the inertial sensor and comparing the output data to the predefined movement pattern and/or reading output data provided by the inertial sensor and calculating a frequency response curve of the inertial sensor.