Electrostatic MEMS Micromirror Comb-Frame Support for Stable Rotation
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Solution Overview
Problem
Existing electrostatic MEMS micromirrors face challenges in expanding the rotation angle range and ensuring stability due to factors like residual stress and external impacts, which can cause buckling and device failure.
Innovation Solution
The design incorporates a comb frame located on both sides of the rotating axis, supporting the micromirror with multiple points and using reinforcement rods to enhance stability, while extending the movable comb near the axis for increased driving force and rotation angle range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the movable comb is extended near the rotating axis to increase driving force, then the rotation angle range is improved, but the device complexity increases
Solution Approach 1:
The movable comb is extended in a direction away from the rotating axis, utilizing the radial dimension to increase the lever arm length. This dimensional change allows the driving force to act at a greater distance from the rotation point, thereby increasing the rotation angle range without adding complex mechanical components
Solution Approach 2:
The design allows the movable comb to dynamically extend and flex during operation, adapting its position to optimize the driving force application. This dynamic configuration enables the structure to achieve greater rotational range while maintaining structural integrity and avoiding excessive complexity
2Stability of the object's composition
If the comb frame is positioned on both sides of the rotating axis to support the micromirror, then the stability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The comb frame is segmented into multiple support points distributed on both sides of the rotating axis. This segmentation allows the load to be distributed across several locations, improving overall stability while each individual support point can be manufactured with standard precision tolerances
Solution Approach 2:
The support structure is designed with varying local properties - the comb frame has different thicknesses and stiffness at different locations, with stronger support where needed and lighter construction where less support is required. This localized optimization improves stability without requiring uniform high manufacturing precision throughout the entire structure
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 improved design increases the moment of inertia and driving force, enhancing the stability and rotation angle range of the micromirror, while suppressing high-order mode interference.
Implementation Method 1
The stationary comb structure is configured to generate electrostatic force with the movable comb structure
Implementation Method 2
a moment of inertia of an area of the electrostatic MEMS micromirror is increased, thereby improving stability of a device
Data Source
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AI summary
An electrostatic MEMS micromirror is provided, and may be used in a device such as a mobile phone, a microphone, a camera, a radar, or an optical switch. The electrostatic MEMS micromirror includes a support beam, a micromirror, and a drive component. The drive component includes a comb frame and a drive comb located in the comb frame. The support beam and the micromirror are connected by using the comb frame. Two sides of the comb frame that are connected to the micromirror are separately located on two sides of a rotating axis determined by an extension line of the support beam. The drive comb includes at least one comb pair. The comb pair includes a movable comb structure and a stationary comb structure. The movable comb structure includes a plurality of movable combs. One end of the movable comb is fastened to the comb frame. The stationary comb structure is configured to generate electrostatic force with the movable comb structure. A distance between a fixed end of the movable comb and the rotating axis is greater than a distance between the other end of the movable comb and the rotating axis. The structure can further improve a rotation angle range and stability of the electrostatic MEMS micromirror.