MEMS Micromirror Stacked Comb Drive for High Duty Cycle
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Solution Overview
Problem
Existing MEMS micromirrors face challenges in achieving a high duty cycle while maintaining a large deflection angle, particularly due to limitations in their drive structure and fabrication processes.
Innovation Solution
The MEMS micromirror design incorporates a stacked structure with first and second bases, and a base plate, featuring movable and fixed combs, elastic beams, and a reinforcing rib under the reflector silicon layer, which improves duty cycle and reduces size while enabling large angle deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If vertical comb driving structure is used to achieve large angular deflection, then deflection angle is improved, but duty cycle deteriorates due to increased structure size
Solution Approach 1:
The patent transitions from a planar comb drive structure to a three-dimensional stacked configuration with multiple bases (first base, second base, base plate) and vertically arranged comb structures. This dimensional change allows the drive structure to achieve large deflection angles through vertical stacking while maintaining a compact footprint, thereby improving duty cycle without sacrificing deflection performance
Solution Approach 2:
The patent implements nested framing structures where inner frames are positioned within outer frames across multiple bases. The first inner frame and second inner frame form an inner frame structure, while first outer frame, second outer frame, and third outer frame form an outer frame structure. This nesting allows compact integration of drive components, reducing overall structure size and improving duty cycle while maintaining large angular deflection capability
2Productivity
If panel-like MEMS micromirror structure is used to achieve high duty cycle, then duty cycle is improved, but deflection angle deteriorates due to chip structure limitations
Solution Approach 1:
The patent employs flexible elastic beams (first elastic beam, second elastic beam) that connect the silicon layer of the reflector to the inner frame. These dynamic elastic elements enable large angular deflection of the mirror while maintaining a compact panel-like structure. The elasticity allows the structure to achieve large deflection angles without requiring a larger chip footprint, thus maintaining high duty cycle
Solution Approach 2:
The patent uses composite material structures including silicon layers, metal layers, and elastic beam materials combined in a multi-layer configuration. The silicon layer of the reflector is supported by a reinforcing rib structure, and metal layers provide additional mechanical properties. This composite approach enables the panel-like structure to achieve large deflection angles while maintaining compact size and high duty cycle
3Manufacturing precision
If reinforcing rib structure is added under reflector silicon layer, then surface smoothness is improved, but device complexity increases
Solution Approach 1:
The patent integrates the reinforcing rib structure with the existing multi-base framework by incorporating it into the first base along with the comb structures and elastic beams. The reinforcing rib is positioned within the first base structure, sharing the same fabrication process and structural support system. This merging approach provides surface smoothness improvement without proportionally increasing device complexity, as the reinforcing function is combined with the existing structural elements
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 design enhances the duty cycle and reduces the size of the MEMS micromirror while achieving large angle deflection in two directions, improving surface smoothness and facilitating commercialization through versatile electrode lead-out forms.
Implementation Method 1
electrostatically driven MEMS micromirrors
Implementation Method 2
a first elastic beam (113), a second elastic beam (116)
Data Source
AI summary
The present disclosure provides a MEMS micromirror with a high duty cycle, a micromirror array, and a preparation method thereof, wherein a plurality of first movable combs and a plurality of first fixed combs of the MEMS micromirror are located under the silicon layer of the reflector, which improves the duty cycle and effectively reduces the size of the MEMS micromirror while achieving large angle deflection in two directions. The silicon layer of the reflector has a reinforcing rib underneath, which effectively improves surface smoothness of the MEMS micromirror when the latter is still or moving. In addition, the MEMS micromirror has a variety of electrode lead-out forms including a double-sided electrode structure, and the electrode lead-out form during actual implantation can be selected as needed, which is conducive to the commercialization of MEMS micromirrors and micromirror arrays.