Mirror Device Rib Configuration for Resonance Control
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Solution Overview
Problem
Existing mirror devices face challenges in effectively suppressing distortion of the mirror surface and ensuring reliability while allowing for good swinging of the movable portion, as existing rib reinforcement methods can increase the moment of inertia and lead to resonance frequency decreases.
Innovation Solution
The mirror device incorporates a rib portion with specific configurations, including first, second, third, and fourth rib portions, and extending portions that intersect the axis in a balanced manner to minimize the moment of inertia and enhance rigidity, preventing damage and peeling, while maintaining effective swinging and resonance suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rib portion is reinforced by connecting rib portions, then reliability is improved, but the moment of inertia of the movable portion around the first axis increases
Solution Approach 1:
The rib portion is designed with different structures in different regions: the first and second rib portions include extending portions that intersect the first axis to provide reinforcement and reliability, while the third and fourth rib portions do not include extending portions that intersect the second axis, thereby avoiding excessive increase in moment of inertia around the first axis. This localized differentiation allows the structure to achieve reliability where needed without compromising swinging performance.
Solution Approach 2:
The rib portion is divided into four distinct rib portions (first, second, third, and fourth) with different configurations. The first and second rib portions have extending portions intersecting the first axis, while the third and fourth rib portions have extending portions that do not intersect the second axis. This segmentation allows independent optimization of each region to balance reliability and moment of inertia.
2Manufacturing precision
If the rib portion is reinforced, then distortion of the mirror surface is suppressed, but the resonance frequency of the movable portion decreases
Solution Approach 1:
The rib portion provides localized reinforcement at strategic locations to suppress distortion of the mirror surface while avoiding excessive reinforcement in regions that would significantly increase the moment of inertia around the first axis. The extending portions of the first and second rib portions intersect the first axis to provide distortion suppression, while the third and fourth rib portions are configured to minimize impact on resonance frequency.
Solution Approach 2:
The moment of inertia of the movable portion around the first axis is carefully controlled by designing the rib portion with specific geometric parameters. The extending portions of the first and second rib portions intersect the first axis at controlled positions and angles, while the third and fourth rib portions are designed with parameters that minimize their effect on the moment of inertia, thereby maintaining resonance frequency while suppressing distortion.
3Strength
If the rib portion is formed to intersect the first axis, then the moment of inertia around the first axis increases, but the swinging performance of the movable portion deteriorates
Solution Approach 1:
The rib portion is segmented into four distinct portions with different configurations relative to the first and second axes. The first and second rib portions include extending portions that intersect the first axis to provide structural strength, while the third and fourth rib portions are configured to minimize interference with the swinging motion around the first axis, thereby balancing strength and swinging performance.
Solution Approach 2:
The rib portion exhibits asymmetric configuration relative to the first and second axes. The first and second rib portions have extending portions that intersect the first axis, while the third and fourth rib portions have extending portions that do not intersect the second axis in the same manner. This asymmetric design allows the structure to achieve the necessary moment of inertia for strength while preserving swinging performance around the first axis.
Data Source
AI summary
In a mirror device, a first rib portion includes a pair of first portions extending toward one side in a first direction and a first extending portion extending between the first portions. A second rib portion includes a pair of second portions extending toward the other side in the first direction and a second extending portion extending between the second portions. A third rib portion includes a pair of third portions extending toward one side in a second direction. A fourth rib portion includes a pair of fourth portions extending toward the other side in the second direction. A rib portion does not include portions formed between the third portions and between the fourth portions and extending to intersect the second axis when viewed in a third direction. The first to fourth portions are portions different from one another.