Interdigitating Vertical Dampers for MEMS Mirror Settling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
MEMS mirrors in optical circuit switches experience ringing due to high quality factor (Q), leading to delays in optical signal switching as the mirror takes time to settle in its new position, which affects the reliability and speed of beam steering.
Innovation Solution
Incorporating dampers with complementary features on the mirror platform and base substrate that interleave to create a damping force through fluid compression, reducing the quality factor and minimizing ringing cycles, thereby enhancing the stability and speed of mirror positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the MEMS mirror is designed with high quality factor (Q) for reduced energy loss, then energy efficiency is improved, but the mirror exhibits prolonged ringing and delayed settling time
Solution Approach 1:
A damping fluid is introduced as an intermediary substance between the mirror and its support structure. This fluid mediates the energy dissipation process by providing viscous damping forces that reduce ringing while minimizing energy loss to the support structure, thereby resolving the contradiction between energy efficiency and settling time
Solution Approach 2:
The quality factor of the MEMS mirror is dynamically adjusted by changing the viscosity parameters of the damping fluid through temperature control. By heating or cooling the fluid, the damping characteristics are modified to achieve optimal balance between energy loss and settling time for different operating conditions
2Productivity
If the mirror settling time is reduced for faster switching, then switching speed is improved, but energy dissipation increases
Solution Approach 1:
A damping fluid is introduced into the cavity beneath the mirror, utilizing fluid dynamics principles. The fluid provides velocity-dependent damping forces that dissipate vibrational energy during settling, enabling faster switching while controlling energy loss through optimized fluid selection and cavity geometry
Solution Approach 2:
The damping characteristics are adjusted by changing physical parameters of the damping fluid, particularly viscosity through temperature control. This allows optimization of the balance between switching speed and energy dissipation based on operational requirements
3Loss of time
If damping structures are added to reduce ringing, then settling time is improved, but device complexity increases
Solution Approach 1:
The support structure serving the mirror is designed to fulfill multiple functions: mechanical support, positioning, and damping. By integrating the damping function into the existing support structure rather than adding separate damping components, the solution reduces settling time while minimizing increases in device complexity
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 implementation of these dampers significantly reduces the quality factor, allowing the mirror to settle faster and reducing sensitivity to external excitations, enabling faster and more reliable optical signal switching.
Implementation Method 1
Incorporating dampers with complementary features on the mirror platform and base substrate that interleave to create a damping force through fluid compression
Implementation Method 2
create a damping force through fluid compression, reducing the quality factor and minimizing ringing cycles
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A microelectromechanical system (MEMS) mirror assembly includes a base substrate defining a cavity and a plurality of first features extending upwards from a bottom of the cavity. The MEMS mirror assembly includes a mirror substrate coupled to the base substrate and defining a MEMS actuator and a MEMS mirror platform. Actuation of the MEMS actuator moves the MEMS mirror platform from a first positional state to a second positional state. The MEMS mirror platform defines a plurality of second features on a side of the MEMS mirror platform facing the base substrate that are sized, shaped, and positioned such that the plurality of second features extend into spaces separating the plurality of first features when the mirror platform is in the second positional state. The MEMS mirror assembly includes a reflective material disposed on a side of the MEMS mirror platform facing away from the base substrate.