Optical Scanning Device Torsion Beam Segmentation
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Solution Overview
Problem
Conventional optical scanning devices face issues with nonlinear oscillation and mirror deformation when attempting to increase resonant frequency, leading to stress and displacement nonlinearity, which affects the precision and effectiveness of light projection.
Innovation Solution
Incorporating a slit parallel to the axis direction in the torsion beams of the optical scanning device, which supports the mirror supporting part from both sides, helps to reduce nonlinear oscillation and prevent mirror deformation by maintaining rigidity and dispersing stress effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the width of the torsion beam is broadened to improve rigidity, then the rigidity is improved, but nonlinearity of displacement is caused
Solution Approach 1:
The torsion beam is divided into multiple segments along its length, with each segment having a different width. This segmentation allows the beam to maintain high rigidity in critical areas while preserving displacement linearity in other areas, resolving the contradiction between strength and precision
2Measurement precision
If the resonant frequency is raised, then higher resolution is achieved, but nonlinear oscillation and mirror deformation occur
Solution Approach 1:
Different portions of the torsion beam are given different local qualities through varying widths. The beam has wider sections for rigidity and narrower sections for flexibility, allowing high resonant frequency operation while maintaining oscillation linearity and preventing mirror deformation
3Measurement precision
If the resonant frequency is raised, then higher resolution is achieved, but stress and mirror deformation are not prevented
Solution Approach 1:
The torsion beam is segmented with varying widths to distribute stress more effectively. This segmentation allows the beam to withstand high resonant frequency operation without excessive stress accumulation, thereby preventing mirror deformation while maintaining high resolution capability
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 minimizes nonlinear oscillation and maintains mirror flatness even at high resonant frequencies, allowing for precise light deflection and improved projection performance.
Implementation Method 1
a pair of torsion beams to support the mirror supporting part from both sides in an axis direction and to drive the mirror supporting part so as to swing the mirror supporting part around the axis by being twisted themselves
Data Source
AI summary
Disclosed is an optical scanning device, including a mirror, a first drive beam configured to swing the mirror around a first axis, and a second drive beam configured to swing the mirror around a second axis, wherein the second drive beam is provided in such a manner that a plurality of beams extending in a direction intersecting with a direction of the second axis are joined with adjacent beams at edge portions thereof, and thereby has a zigzag shape, and each of the plurality of beams includes a rib extending in a direction of a width of the beam.