MEMS Mirror Beam Configuration for Two-Axis Twisting
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Solution Overview
Problem
Existing MEMS mirrors face a challenge in increasing their figure of merit while minimizing dead space, which restricts optical path efficiency and system size.
Innovation Solution
A MEMS device with a mirror portion supported by symmetrically disposed first and second beams, and a third beam orthogonal to the first rotation axis, utilizing superimposed vibrations of opposite and same phases to enable two-axis twisting operations, reducing dead space while maintaining or improving the figure of merit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a coupled vibration structure is used to increase the figure of merit, then the figure of merit improves, but the dead space increases due to the counterweight
Solution Approach 1:
The invention extracts and eliminates the counterweight component from the coupled vibration structure. By removing the counterweight while maintaining the essential vibration coupling function through the specific beam configuration (first and second beams symmetrically disposed with respect to the rotation axis), the patent achieves high figure of merit without the associated dead space penalty
Solution Approach 2:
The invention replaces the traditional mechanical counterweight-based coupled vibration structure with an alternative mechanical configuration using symmetrically disposed beams. This substitution maintains the vibration coupling effect necessary for high figure of merit while eliminating the space-consuming counterweight component
2Adaptability or versatility
If an action point is provided outside an axis to increase the figure of merit, then the figure of merit improves, but the dead space increases due to the large vibration input unit
Solution Approach 1:
The invention employs asymmetric beam design where the first and second beams are symmetrically disposed with respect to the rotation axis but have different configurations. This controlled asymmetry enables the action point to be positioned outside the axis for improved figure of merit while keeping the vibration input unit compact
Solution Approach 2:
The invention repositions the action point in a different spatial dimension (outside the rotation axis) to achieve lever arm multiplication for higher figure of merit. The symmetric beam configuration ensures this dimensional shift does not create excessive dead space
3Area of stationary object
If the dead space is reduced, then the optical path efficiency improves, but the figure of merit may decrease
Solution Approach 1:
The invention segments the mirror support structure into multiple functional beams (first beam, second beam symmetrically disposed, and third beam orthogonally disposed). This segmentation allows each beam to contribute differently to the overall performance, enabling compact dead space while maintaining high figure of merit through distributed structural functions
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 solution allows for improved figure of merit and reduced dead space, enabling efficient optical scanning with enhanced performance and compact system design.
Implementation Method 1
a first vibration input unit and a second vibration input unit symmetrically disposed with respect to the first rotation axis. superimposing a first vibration of an opposite phase and a second vibration of a same phase and inputting the vibrations to each of a first vibration input unit and a second vibration input unit
Implementation Method 2
a mirror portion that twists and vibrates about a first rotation axis at a first vibration frequency and twists and vibrates about a second rotation axis orthogonal to the first rotation axis at a second vibration frequency
Data Source
AI summary
A MEMS device includes: a first beam and a second beam that are symmetrically disposed with respect to a first rotation axis of a mirror portion, in which a third beam is disposed on a side opposite to the first beam and the second beam with reference to a line that is orthogonal to the first rotation axis and passes through a center of gravity of the mirror portion.