MEMS Mirror Backside Reinforcement with Contour Points
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Solution Overview
Problem
Micro-electro mechanical system (MEMS) scanners face stress concentration issues at weak points, leading to potential breakage during high-speed operation, which limits their durability and reliability.
Innovation Solution
The implementation of a backside reinforcement structure with contour points that concentrate and distribute stress away from weak areas, such as the transition points between the top silicon and transition layers, along with the use of cavities to reduce mass and enhance operational performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the reinforcement structure is maximized to keep the reflecting layer flat during high speed rotation, then mirror flatness is improved, but stress at the transition points increases leading to potential breakage
Solution Approach 1:
The patent applies local quality by introducing contour points at specific locations on the reinforcement structure where stress naturally concentrates. These contour points are strategically positioned to redirect stress away from the vulnerable transition area between the top silicon layer and transition layer, while maintaining overall mirror flatness. This localized stress management allows the reflecting layer to remain flat without subjecting the transition points to excessive stress that would cause breakage.
2Productivity
If the MEMS scanner operates at higher frequencies, then productivity is improved, but stress on the reinforcement structure increases leading to breakage
Solution Approach 1:
The patent implements preliminary action by pre-designing the reinforcement structure with contour points that anticipate and prepare for stress concentration during high-frequency operation. These contour points are built into the structure before operation, creating predetermined stress pathways that redirect forces away from weak transition areas. This preliminary structural configuration enables the MEMS scanner to operate at higher frequencies without risking breakage, as the stress management mechanism is already in place before the high-stress operation begins.
3Weight of moving object
If cavities are created to reduce mass, then weight is improved, but structural strength may be compromised
Solution Approach 1:
The patent applies segmentation by introducing cavities into the reinforcement structure, dividing the solid mass into separate regions. These cavities strategically remove material from areas where full structural support is not needed, thereby reducing the overall mass of the MEMS scanner. The cavities are positioned and sized to maintain structural integrity in critical load-bearing areas while achieving mass reduction, allowing the device to operate more efficiently without compromising the reinforcement structure's ability to maintain mirror flatness.
Data Source
AI summary
A micro-electro mechanical system (MEMS) scanner has a backside reinforcement structure configured to concentrate stress which is exerted against the reinforcement structure at contour points. The reinforcement structure is attached to an underside of a mirror to maintain mirror flatness. Characteristics and features of the contour points are variable based on the specific application, including considerations for the design of the MEMS scanner, mirror, and reinforcement structure. The contour points are configured for concentration of stress to relieve stress from relatively weaker areas on the reinforcement structure, thereby increasing reliability and performance of the MEMS scanner. For example, a point of failure on the reinforcement structure may be where a top silicon layer and transition layer (e.g., silicon oxide layer) adjoin. Implementation of the contour points can concentrate stress at the contour points and thereby relieve stress from the weaker areas.