Resonant Mirror Phase Synchronization for Video Display Jitter
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Solution Overview
Problem
In video display systems using torsional hinged mirrors, synchronizing the high speed scanning mirror with the low frequency positioning mirror is challenging due to varying resonant frequencies and non-periodic data frame reception, leading to image distortions and jitter.
Innovation Solution
A method is employed to generate a cyclic drive signal for the low frequency mirror, adjusting its phase difference with the high speed mirror to maintain a constant value, ensuring synchronization with incoming video frame rates and precise positioning of scan lines, using a sinusoidal or triangular drive signal with adjustable peak portions and discrete values stored in a circular buffer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the high speed mirror is driven at its resonant frequency to maintain beam sweep amplitude, then the image quality is improved, but the synchronization with the low frequency mirror becomes difficult due to frequency variations
Solution Approach 1:
The system dynamically adjusts the phase of the low frequency mirror drive signal based on real-time detection of the high speed mirror's resonant frequency. This dynamic phase adjustment allows the system to maintain constant phase difference and proper synchronization even as the resonant frequency varies due to manufacturing tolerances or environmental conditions.
Solution Approach 2:
The system employs feedback mechanisms to detect the actual resonant frequency of the high speed mirror and uses this information to adjust the phase of the low frequency mirror drive signal. This closed-loop approach ensures that the phase difference remains constant despite frequency variations, resolving the synchronization problem.
2Stability of the object's composition
If the low frequency mirror drive signal is synchronized to the incoming video frame rate, then the frame stability is improved, but the phase difference with the high speed mirror varies causing scan line positioning errors
Solution Approach 1:
The system dynamically adjusts the phase of the low frequency mirror drive signal while maintaining its synchronization with the video frame rate. This dynamic phase adjustment compensates for the phase drift that would otherwise occur between the low frequency mirror and the high speed mirror, ensuring that scan lines are positioned accurately on the display surface.
3Ease of operation
If the high speed mirror oscillates at a frequency that is an exact even multiple of the low frequency mirror, then the synchronization is simplified, but the image quality deteriorates due to resonance requirements
Solution Approach 1:
The invention extracts the phase relationship from the frequency relationship. Instead of relying on a fixed frequency multiple relationship between the high speed and low frequency mirrors, the system independently controls the phase of the low frequency mirror drive signal. This separation allows the high speed mirror to operate at its optimal resonant frequency while maintaining proper synchronization through phase adjustment rather than frequency coupling.
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 ensures stable and high-quality image reproduction by maintaining constant phase difference and precise positioning of scan lines, even with varying frame rates and non-periodic data reception, preventing image distortions and jitter.
Implementation Method 1
the high frequency mirror must run or oscillate at substantially its resonant frequency, since driving a high-Q mirror at a frequency only slightly different than the resonant frequency will result in a significant decrease in the amplitude of the beam sweep
Implementation Method 2
generating a cyclic drive signal (such as for example a sinusoidal or repetitive triangular drive signal) to position the low frequency mirror
Data Source
AI summary
System and method for synchronizing the low speed mirror movement of a mirror display system with incoming frame or video signals, and synchronizing buffered lines of video data to the independently oscillating scanning mirror. According to one embodiment of the invention, the peak portions of the low speed cyclic drive signal are synchronized with the incoming frames of video by compressing or expanding the peak portion or turn around portion so that each video frame begins at the same location on the display screen. The actual position of the high frequency mirror is determined by sensors and a “trigger” signal is generated to distribute the signals for each scan line such that the scan lines are properly positioned on the display.