Asymmetric Resonance Optical Deflection for Temperature Stability
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Solution Overview
Problem
Optical deflection apparatuses face significant challenges in maintaining a stable deflection angle due to variations in ambient temperature, which can lead to resonance characteristic changes and potential damage.
Innovation Solution
The apparatus employs a mirror unit supported by elastic units with asymmetric resonance frequency characteristics, where the drive frequency is set on the gentler slope side of the resonance curve, utilizing piezoelectric elements to control the mirror's rotation and maintain a consistent deflection angle despite temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the drive frequency is set at the resonance frequency to maximize deflection angle, then the deflection angle is maximized, but the deflection angle becomes highly sensitive to temperature changes causing significant variation
Solution Approach 1:
The patent applies asymmetry by intentionally selecting an asymmetric frequency point on the resonance curve where the slope is smaller on one side. This asymmetric selection creates a drive frequency that is offset from the peak resonance frequency, resulting in a flatter response characteristic that reduces sensitivity to temperature-induced frequency shifts while maintaining adequate deflection angle.
Solution Approach 2:
The patent changes the operating parameter (drive frequency) from the peak resonance frequency to a specific frequency point on the resonance curve where the slope is minimized. This parameter change transforms the system from being highly sensitive to temperature variations to being relatively insensitive, thereby improving stability while maintaining functionality.
2Reliability
If the drive frequency is set away from resonance frequency to reduce temperature sensitivity, then temperature stability improves, but the deflection angle decreases
Solution Approach 1:
The patent optimizes the drive frequency parameter to a specific value on the resonance curve that balances two competing requirements: being close enough to resonance to maintain large deflection angle, yet offset enough to reduce temperature sensitivity. This optimized parameter selection achieves both goals simultaneously rather than requiring a trade-off.
Solution Approach 2:
The patent skips the peak resonance frequency point and selects a frequency point slightly offset from the peak where the slope is smaller. This skipping approach allows the system to bypass the highly sensitive region while remaining in the high-deflection-angle region of the resonance curve.
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 suppresses changes in the deflection angle caused by temperature variations, preventing potential damage and ensuring stable operation.
Implementation Method 1
at least one drive unit configured to elastically deform the pair of elastic supporting units
Implementation Method 2
a pair of elastic supporting units configured to rotatably support the mirror unit around a predetermined axis
Implementation Method 3
the at least one drive unit is configured to cause the mirror unit to resonate by utilizing elastic deformation of the pair of elastic supporting units
Data Source
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AI summary
An optical deflection apparatus includes a mirror unit, a pair of elastic supporting units configured to rotatably support the mirror unit around a predetermined axis, at least one drive unit configured to elastically deform the pair of elastic supporting units, and a drive control unit configured to input a drive frequency into the at least one drive unit so as to control the at least one drive unit, wherein the at least one drive unit is configured to cause the mirror unit to resonate by utilizing elastic deformation of the pair of elastic supporting units so as to rotate the mirror unit around the predetermined axis and deflect luminous flux incident on the mirror unit, wherein the pair of elastic supporting units are configured to support the mirror unit such that, in a resonance characteristic curve indicating resonance characteristics of the optical deflection apparatus, a slope on one side of a resonance frequency becomes smaller than a slope on another side of the resonance frequency, the one side being one of a higher frequency side or a lower frequency side relative to the resonance frequency, and wherein the drive frequency is a frequency on the one side.