Optical Deflector Meandering Beam Drive for Swing Speed Uniformity
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Solution Overview
Problem
Existing optical deflector drive devices fail to minimize fluctuations in mirror swing speed due to slight asymmetry in the structure of the drive unit, leading to uneven luminance and distortion in images formed.
Innovation Solution
An optical deflecting device with a mirror supported by a drive unit featuring continuously meandering beams and piezoelectric members, where two voltages with non-similar waveforms are applied in parallel to adjacent beams to adjust the swing speed and suppress fluctuations, using a sawtooth-wave and inverse sawtooth-wave voltage with phase shifts and different amplitudes to cancel mechanical resonance components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional drive unit with symmetrical structure is used, then the device is easy to manufacture, but the swing speed fluctuations cannot be minimized due to slight asymmetries
Solution Approach 1:
The patent intentionally introduces asymmetry in the drive unit structure by making the beams have different lengths (first beam longer than second beam) and applying non-similar voltages to piezoelectric members on opposite sides. This deliberate asymmetry compensates for manufacturing tolerances and minimizes swing speed fluctuations, resolving the contradiction between manufacturing precision and ease of manufacture.
Solution Approach 2:
The patent changes the parameters of the drive voltages applied to the piezoelectric members, specifically using non-similar voltages with different amplitudes and waveforms (sawtooth and inverse sawtooth waves with phase shifts). This parameter adjustment allows compensation for structural asymmetries and achieves uniform swing speed, addressing the technical contradiction.
2Manufacturing precision
If symmetrical voltages are applied to piezoelectric members, then the control is simple, but mechanical resonance components cause swing speed fluctuations
Solution Approach 1:
The patent applies non-similar voltages (different amplitudes and waveforms) to piezoelectric members on opposite sides of the mirror, creating an asymmetrical control scheme that cancels mechanical resonance components. This resolves the contradiction by using asymmetrical voltage control to achieve uniform swing speed while managing the increased control complexity.
Solution Approach 2:
The patent converts the harmful mechanical resonance components into a beneficial effect by using non-similar voltages to cancel out the resonance. The phase-shifted sawtooth and inverse sawtooth waves are designed to counteract the resonance, transforming what would be a problem into a solution for achieving uniform swing speed.
3Ease of manufacture
If the drive unit structure is simplified, then the ease of manufacture increases, but the ability to suppress swing speed fluctuations decreases
Solution Approach 1:
Rather than complicating the physical structure, the patent achieves swing speed uniformity by changing the electrical parameters (voltage amplitudes and waveforms) applied to a simplified symmetrical drive unit structure. This resolves the contradiction by maintaining structural simplicity while using parameter adjustment to achieve precision.
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 effectively minimizes swing speed fluctuations, ensuring linear optical scanning and high-quality image formation with reduced uneven luminance and distortion, even in slightly asymmetrical drive unit structures.
Implementation Method 1
a plurality of first piezoelectric members respectively provided to the plurality of first beams to swing the mirror around a first axis to deflect light incident on the reflecting surface of the mirror
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An optical deflecting device (1000) includes a mirror (110) having a reflecting surface and a support unit (400) to support the mirror (110). The support unit (400) includes a first drive unit (250). The first drive unit (250) includes a plurality of continuously meandering first beams (108a, 108b) and a plurality of first piezoelectric members (11, 12) respectively provided to the plurality of first beams (108a, 108b) to swing the mirror (110) around a first axis to deflect light incident on the reflecting surface of the mirror (110). Two voltages having non-similar waveforms are respectively applied in parallel to each two of the first piezoelectric members (11, 12) respectively provided to adjacent two of the first beams (108a, 108b).