Zigzag Drive Beam Asymmetry for Optical Scanning Ringing
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Solution Overview
Problem
Optical scanning devices using a sawtooth voltage for mirror rotation often experience ringing due to resonant oscillations, leading to image quality degradation, and existing solutions require complex signal processing or filtering to control this issue.
Innovation Solution
The optical scanning device employs a zigzag-shaped drive beam with varying turn-back part weights to distribute vibration energy, reducing the gain in specific normal modes of vibration and controlling ringing mechanically without the need for wide band filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a sawtooth voltage is used to drive the mirror rotation, then the scanning speed and productivity are improved, but ringing due to resonant oscillations occurs degrading image quality
Solution Approach 1:
The drive beam is designed with asymmetric weight distribution through varying turn-back part weights. The zigzag-shaped drive beam includes multiple beams with turn-back parts where the weight of the first turn-back part differs from the weight of the second turn-back part. This asymmetric configuration disrupts resonant oscillations and reduces ringing effects while maintaining the sawtooth voltage-driven scanning performance, thereby preserving image quality without sacrificing scanning speed.
2Manufacturing precision
If complex signal processing or filtering is applied to control ringing, then image quality is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex electronic signal processing systems with a mechanical solution. Instead of using filters or controllers to suppress ringing, the invention modifies the physical structure of the drive beam itself. The asymmetric weight distribution in the zigzag-shaped drive beam mechanically suppresses resonant oscillations at their source, eliminating the need for additional sensors, controllers, or signal processing circuits, thus maintaining simple device architecture while improving image quality.
3Manufacturing precision
If wide band filtering is used to reduce ringing, then image quality is improved, but the rectilinear section of scanning is reduced
Solution Approach 1:
The asymmetric weight distribution in the drive beam is designed in advance to prevent resonant oscillations before they can degrade the scanning waveform. By configuring the turn-back parts with different weights, the system proactively suppresses ringing effects during the scanning operation. This preliminary mechanical anti-action maintains the linearity of the scanning waveform throughout the rectilinear section, preserving the full scanning range without requiring filtering that would truncate the useful scanning portion.
Data Source
AI summary
An optical scanning device includes a drive beam configured to support a mirror, and a drive source provided on the drive beam and configured to oscillate the mirror about a predetermined axis passing through the center of the light reflecting surface of the mirror. The drive beam includes multiple beams each extending in a direction perpendicular to the predetermined axis and one or more turn-back parts each connecting ends of adjacent beams, and has a zigzag shape as a whole. The multiple beams include a first beam, a second beam adjacent to the first beam, and a third beam adjacent to the second beam, the one or more turn-back parts include a first turn-back part connecting the first and second beams and a second turn-back part connecting the second and third beams, and the first and second turn-back parts are different in weight.