MEMS Mirror Frequency Control for Flicker-Free Lissajous Scanning
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Solution Overview
Problem
Existing MEMS mirrors used for image projection or detection using Lissajous figures can cause undesirable artifacts like flickering due to their operation, and achieving high energy efficiency and high-contrast projections is challenging, especially in augmented reality applications.
Innovation Solution
Control the oscillation movements of a MEMS mirror with respect to two non-parallel axes using specific frequency ratios and ranges, synchronously adjusting the first and second drive frequencies to minimize flickering and enhance energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If resonant oscillation movements are used to scan the field of view, then energy efficiency is improved, but flickering artifacts are generated
Solution Approach 1:
The patent changes the frequency parameters of the oscillation movements by establishing a specific frequency ratio relationship between the first and second drive frequencies. This parameter modification allows the system to maintain resonant operation for energy efficiency while avoiding frequency combinations that cause visible flickering artifacts in the projected image.
Solution Approach 2:
The patent employs periodic resonant oscillation movements of the MEMS mirror to scan the field of view. By controlling the periodicity and frequency ratio of these oscillations, the system achieves efficient energy utilization while the specific frequency relationship prevents the generation of flickering artifacts that would be visible to the human eye.
2Use of energy by moving object
If Lissajous figure scanning is used for image projection, then energy efficiency is improved, but image contrast is reduced
Solution Approach 1:
The patent modifies the frequency parameters of the Lissajous figure scanning by establishing a specific ratio relationship between the first and second drive frequencies. This parameter change optimizes the scanning trajectory to achieve better image contrast while maintaining the energy efficiency benefits of resonant operation.
3Productivity
If drive frequencies are increased to improve scanning speed, then productivity is improved, but energy consumption increases
Solution Approach 1:
The patent utilizes resonant mechanical vibration of the MEMS mirror at specific frequencies to achieve efficient scanning. By operating at resonant frequencies rather than arbitrary high frequencies, the system achieves good scanning performance with lower energy consumption, as the resonant oscillation requires less driving force to maintain the oscillation amplitude.
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 method enables high-contrast, flicker-free image projection or detection by precisely controlling the MEMS mirror's oscillation movements, ensuring energy efficiency and robust performance in augmented reality applications.
Implementation Method 1
controlling the oscillation movement of the MEMS mirror with respect to the first oscillation axis L1 with a first drive frequency FR1 greater than zero, (B) controlling the oscillation movement of the MEMS mirror with respect to the second oscillation axis L2 with a second drive frequency FR2 greater than zero, wherein the first oscillation axis L1 and the second oscillation axis L2 are defined in such a way and the first drive frequency FR1 and the second drive frequency FR2 are designed in such a way that the first drive frequency FR1 is lower than the second drive frequency FR2
Data Source
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AI summary
The present invention relates to a method for driving a resonant oscillation movement of a MEMS mirror with respect to a first oscillation axis L1 and a resonant oscillation movement of the MEMS mirror with respect to a second oscillation axis L2, comprising the steps of: (A) controlling the oscillation movement of the MEMS mirror with respect to the first oscillation axis L1 with a first drive frequency FR1 greater than zero, (B) controlling the oscillation movement of the MEMS mirror with respect to the second oscillation axis L2 with a second drive frequency FR2 greater than zero, wherein the first oscillation axis and the second oscillation axis are defined in such a way and the first drive frequency FR1 and the second drive frequency FR2 are designed in such a way that the first drive frequency FR1 is lower than the second drive frequency FR2.