Optical Reflection Element Joint Beam Width Design
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Solution Overview
Problem
Conventional optical reflecting devices face challenges in achieving high-frequency drive with large displacement while maintaining mechanical strength, as increased scan rate requires longer torsion bars, leading to device enlargement and decreased scan rate.
Innovation Solution
The optical reflecting device features a configuration with joints having a greater beam width than vibration parts, distributing stress and increasing mechanical strength, allowing for high-frequency drive with large rotation angles without enlarging the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the torsion bar is extended to increase the scan rate, then the device size increases, but the scan rate decreases
Solution Approach 1:
The patent changes the geometric parameters of the joints, specifically making the beam width in the direction orthogonal to the first axis greater than the beam width of the vibration parts. This parameter change increases the resonance frequency and allows for smaller torsion bar lengths while maintaining or improving scan rate performance.
Solution Approach 2:
The patent employs vibration parts that utilize dynamic vibration to rotate the mirror part. By connecting the central portion of the vibration parts to the joints and both ends to the fixed part, the system uses vibrational motion to achieve rotation, thereby increasing the scan rate without requiring longer torsion bars.
2Productivity
If the mirror part is driven at high frequency with large rotation angle, then the stress on joints increases, but the mechanical strength decreases
Solution Approach 1:
The patent optimizes the joint geometry by making the beam width orthogonal to the first axis greater than the beam width of the vibration parts. This parameter change distributes stress more effectively across the joint structure, reducing stress concentration while enabling high-frequency operation with large rotation angles.
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 configuration enhances the resonance frequency and mechanical deflection angle, enabling efficient high-frequency operation while maintaining a compact size and preventing stress concentration.
Implementation Method 1
piezoelectric layers 10 for rotating mirror part 9... When piezoelectric layers 10 are energized, they expand or contract. Due to this expansion or contraction, vibrating beams 4 are twisted to rotate mirror part 9.
Data Source
AI summary
An optical reflecting device includes a mirror part, a pair of joints, a pair of vibration parts, a plurality of driving parts, and a fixed part. Each of the joints has a first end connected to respective one the facing positions to each other on the mirror part and a second end opposite to the first end, and extends along a first axis. Each of the vibration parts has a central portion connected to the second end of respective one of the joints. A plurality of driving parts are disposed in each of the pair of vibration parts, and rotate the mirror part. Both ends of each of the pair of vibration parts are connected to the fixed part. The beam width defined as the length of each of the joints in a direction orthogonal to the first axis is greater than the beam width of each of the pair of vibration parts.