MEMS Mirror Scanning Device Resonance Frequency Drift
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Solution Overview
Problem
Existing scanning devices with MEMS mirror mechanisms face instability in image display due to variations in resonance frequency caused by ambient temperature changes, leading to deviations in the corresponding relationship between horizontal and vertical drive signals.
Innovation Solution
A scanning device with a control unit that generates synchronized drive signals for the MEMS mirror mechanism, ensuring that the outgoing and incoming periods correspond to lighting-on and lighting-off periods, and adjusts the frequency of the drive signals to match the resonance frequency of the mirror, thereby stabilizing the scanning process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the resonance frequency of the mirror is adjusted to match the drive signal frequency, then scanning stability is improved, but when temperature variations cause resonance frequency drift, the correspondence between horizontal and vertical drive signals deviates, degrading display stability
Solution Approach 1:
The control unit continuously monitors the actual resonance frequency of the mirror and dynamically adjusts the drive signal frequency to maintain synchronization. This feedback mechanism ensures that even when temperature variations cause resonance frequency drift, the drive signals remain synchronized with the mirror's actual resonant state, preventing display instability.
Solution Approach 2:
The system transitions from a static frequency matching approach to a dynamic adjustment mechanism. The control unit continuously adapts the drive signal frequency based on real-time resonance frequency measurements, allowing the system to respond to temperature variations and maintain optimal scanning performance under changing environmental conditions.
2Device complexity
If the drive signal frequency is fixed, then the system is simple to control, but when resonance frequency varies due to temperature changes, synchronization between horizontal and vertical scanning is lost
Solution Approach 1:
The control unit implements a feedback loop that continuously measures the mirror's resonance frequency and adjusts the drive signal frequency accordingly. This feedback mechanism adds minimal complexity while significantly improving synchronization accuracy, as it only requires monitoring and adjusting the frequency parameter rather than redesigning the entire control system.
Solution Approach 2:
The system dynamically changes the frequency parameter of the drive signal based on measured resonance frequency variations. By focusing the adaptation on a single critical parameter (frequency) rather than redesigning the entire control architecture, the system maintains relative simplicity while achieving reliable synchronization under varying temperature conditions.
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 solution ensures stable scanning and image display by minimizing deviations between drive signals, even when the resonance frequency varies, resulting in improved image quality and reduced flicker phenomena.
Implementation Method 1
an MEMS mirror mechanism that includes a mirror that reflects the laser light emitted from the light source
Implementation Method 2
the first drive signal is an electric signal for resonating the mirror with respect to the first axial line as a central line
Implementation Method 3
a scanning device that performs scanning with laser light by using a MEMS (micro electro mechanical systems) mirror mechanism
Data Source
AI summary
A scanning device includes an MEMS mirror mechanism that swings a mirror with respect to a first axial line as a central line and swings the mirror with respect to a second axial line as a central line, and a control unit that generates a first drive signal for swinging the mirror with respect to the first axial line, and a second drive signal for swinging the mirror with respect to the second axial line. The control unit generates the first drive signal and the second drive signal so that m times of reciprocation of an irradiation region in a first direction and one time of reciprocation of the irradiation region in a second direction correspond to each other by repeating generation of a second signal element constituting the second drive signal to correspond to a first signal element in a period equal to or less than one cycle in the first drive signal.