MEMS Mirror Bidirectional Rotation via Dual-Frequency Resonance
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Solution Overview
Problem
Existing MEMS scanning mirror systems have complex designs due to the need for bidirectional rotation and electrical isolation, which complicates the integration of actuators and mirror components.
Innovation Solution
A simplified design where actuators are coupled to a frame around the mirror, allowing for high-frequency and low-frequency periodic movements to rotate the mirror about two axes, with the mirror and frame having distinct resonant frequencies, enabling efficient rotation and amplification of motion through elastic coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If actuators are directly coupled to the mirror for bidirectional rotation, then the mirror can achieve rotation about two axes, but the design complexity increases due to the need for electrical isolation and integration of multiple actuators
Solution Approach 1:
The system is divided into two independent rotational systems: a fast axis rotation system with actuators directly coupled to the mirror, and a slow axis rotation system with actuators coupled to the frame. This segmentation allows each subsystem to be optimized independently, reducing overall design complexity while maintaining bidirectional rotation capability
Solution Approach 2:
The frame acts as an intermediary element that couples the slow-axis actuators to the mirror. This intermediary structure simplifies the design by providing a mechanical interface that eliminates the need for complex electrical isolation schemes, as the frame naturally isolates the electrical connections for the two rotational axes
2Device complexity
If actuators are placed around the frame rather than directly on the mirror, then the design is simplified and electrical isolation is easier, but the direct coupling between actuators and mirror is reduced
Solution Approach 1:
The system employs dynamic coupling where the frame and mirror are elastically connected, allowing the actuators on the frame to dynamically transmit motion to the mirror. The elastic connection enables the system to respond at different frequencies for each axis, optimizing both the simplified design and the response speed
Solution Approach 2:
The system utilizes different resonant frequencies for the fast and slow axes, with the fast-axis actuators operating at a higher frequency range and the slow-axis actuators operating at a lower frequency range. This parameter separation allows the distributed actuator configuration to maintain effective control while simplifying the overall design
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 approach simplifies the design by allowing actuators to be placed away from the mirror, reducing complexity and enhancing the rotational capabilities of the MEMS mirror system while maintaining effective bidirectional scanning.
Implementation Method 1
The mirror has a first resonant frequency and the frame including the mirror has a second resonant frequency. The low frequency of the second periodic movement is equal to one of the first and the second resonant frequencies, and the high frequency of the first periodic movement is equal to the other one of the first and the second resonant frequencies.
Implementation Method 2
The mirror is coupled by springs to the frame so the mirror is rotatable about a first axis. The frame has pivots each coupled by springs to actuators so the frame is rotatable about a second axis.
Data Source
AI summary
A micro-electro-mechanical system (MEMS) mirror system has an actuator that imparts a motion with a first periodic movement of high frequency superimposed a second periodic movement of low frequency to a frame and a mirror coupled to the frame so that the mirror rotates about two axes. The mirror is coupled by springs to the frame so the mirror is rotatable about a first axis. The frame has pivots each coupled by springs to actuators so the frame is rotatable about a second axis. The mirror has a first resonant frequency and the frame including the mirror has a second resonant frequency. The low frequency of the second periodic movement is equal to one of the first and the second resonant frequencies, and the high frequency of the first periodic movement is equal to the other one of the first and the second resonant frequencies.