MEMS Mirror Periodic Driving for Vibration-Free Scanning
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Solution Overview
Problem
MEMS devices experience detrimental vibrations when their position is changed abruptly, leading to increased settling time and degraded sensor performance, especially during rapid scanning, as existing methods require slow scanning to avoid excitation of mechanical resonances.
Innovation Solution
A method involving a MEMS mirror driven by a periodic voltage using the piezoelectric effect, where the motion is modeled as a damped harmonic oscillator, allowing for rapid scanning without unwanted vibrations by ensuring the periodic force remains constant, thereby eliminating transient vibrations and enabling faster data acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the MEMS device is scanned rapidly through a range of positions, then productivity is improved, but vibrations are excited leading to degraded measurement precision
Solution Approach 1:
The patent applies periodic driving forces at the fundamental resonance frequency of the MEMS device to maintain continuous periodic motion. By using a periodic drive signal that matches the resonant frequency, the system sustains oscillations without transient vibrations, enabling rapid scanning while maintaining measurement precision through synchronized detection.
Solution Approach 2:
The patent changes the driving approach from abrupt position changes to continuous periodic forcing at resonant frequency. By adjusting the drive parameters to match the system's natural resonance, the transition from transient to steady-state periodic motion is achieved, eliminating settling time and enabling rapid accurate measurements.
2Measurement precision
If the MEMS device is scanned slowly to avoid exciting mechanical resonances, then measurement precision is improved, but productivity deteriorates due to increased measurement time
Solution Approach 1:
The system uses periodic driving forces at the fundamental resonance frequency to maintain continuous periodic motion. This approach eliminates the need for slow scanning by sustaining steady-state oscillations where measurements can be taken at any point in the cycle, achieving both high precision and rapid data acquisition.
Solution Approach 2:
The patent implements continuous periodic motion rather than intermittent scanning with settling periods. By maintaining uninterrupted periodic oscillations driven at resonance, the system eliminates idle settling time and enables continuous measurement acquisition throughout the oscillation cycle, maximizing productivity without sacrificing precision.
3Productivity
If abrupt position changes are applied to the MEMS device, then productivity is improved through rapid scanning, but harmful vibrations are generated that degrade sensor performance
Solution Approach 1:
The patent replaces abrupt position changes with continuous periodic forcing at the fundamental resonance frequency. This transforms harmful transient vibrations into useful steady-state periodic motion, where the oscillations are predictable and can be synchronized with detection, enabling rapid scanning without harmful vibrations.
Solution Approach 2:
The system converts what would normally be harmful resonant vibrations into a beneficial periodic motion state. By deliberately driving at the resonance frequency with periodic forces, the vibrations become predictable and synchronized, allowing measurements to be taken during the periodic cycles rather than waiting for settling, thus transforming the harmful effect into a useful measurement mechanism.
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 reduces the waiting time for accurate measurements by maintaining purely periodic motion, allowing for faster data acquisition over a range of mirror positions without waiting for vibrations to settle, thus enhancing sensor performance during rapid scanning.
Implementation Method 1
The motion is induced via the piezoelectric effect in which an applied electrical potential induces mechanical movement.
Data Source
AI summary
The present invention relates to a MEMS device and related methods comprising a mirror for the measuring of light frequency. The MEMS mirror may rotate around a pivot point and is driven by a periodic force for continuous bi-directional motion without transient vibrations. The periodic force may further comprise transient functions comprising special waveforms when at the turn-around point of the bi-directional rotation.