Optical Scanning Device Center of Gravity Alignment
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Solution Overview
Problem
Optical scanning devices experience reduced image quality due to ringing caused by resonant oscillation and misalignment of the mirror's rotation axis, leading to vertical and horizontal oscillations that affect light scanning.
Innovation Solution
An optical scanning device design where the center of gravity of the mirror and its support structure is aligned on the rotation axis, optimizing weight balance to prevent ringing, using a configuration with asymmetrical weight distribution and piezoelectric elements to control the mirror's rotation, and applying a sawtooth voltage waveform to maintain scanning speed consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a sawtooth voltage is used to drive the optical scanning device, then the scanning speed consistency is improved, but resonant oscillation of the mirror occurs causing ringing that reduces image quality
Solution Approach 1:
The patent applies counterweight by adding weight to the counterweight portion of the mirror support structure to balance the moment of the driving portion. This creates a balanced rotation axis that reduces resonant oscillation and ringing when the mirror is driven by sawtooth voltage, thereby maintaining image quality while preserving scanning speed consistency.
2Ease of operation
If the weight of the driving portion of the mirror support structure is increased to improve rotation control, then the rotation control is improved, but the center of gravity shifts away from the rotation axis causing misalignment and reducing image quality
Solution Approach 1:
The patent uses a counterweight portion with adjustable weight to offset the moment created by the driving portion. This allows the rotation axis to be precisely positioned at the center of the light reflection surface while maintaining adequate driving torque, thus achieving both good rotation control and precise axis alignment for high image quality.
Solution Approach 2:
The patent employs adjustable weights in the counterweight portion that can be positioned at different locations or have different magnitudes. This parameter adjustment capability allows optimization of the moment balance to achieve precise rotation axis alignment while maintaining effective rotation control.
3Manufacturing precision
If asymmetrical weight distribution is used to prevent misalignment of the rotation axis, then the rotation axis alignment is improved, but the device complexity increases due to additional weight adjustment mechanisms
Solution Approach 1:
The patent employs asymmetrical weight distribution between the driving portion and counterweight portion of the mirror support structure. This asymmetry is deliberately designed to balance moments around the rotation axis, achieving precise alignment without requiring complex active adjustment mechanisms during operation.
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 solution effectively reduces vertical and horizontal oscillations, preventing ringing and maintaining image quality by aligning the center of gravity with the rotation axis and optimizing weight distribution, allowing for a highly linear drive waveform that secures a usable section for image display.
Implementation Method 1
first driving sources disposed on the first driving beams and configured to cause the mirror to rotate
Data Source
AI summary
An optical scanning device includes a mirror including a light reflection surface, a mirror support structure that supports the mirror, a pair of first driving beams connected to the mirror support structure and disposed on the corresponding sides of the mirror support structure, first driving sources disposed on the first driving beams and configured to cause the mirror to rotate around a first axis that passes through the center of the light reflection surface, and a fixed frame that supports the first driving beams. The center of gravity of the mirror and the mirror support structure is located on the first axis.