MEMS Actuator Asymmetrical Spring Tilt-Free Movement
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Solution Overview
Problem
Conventional MEMS actuators face challenges in achieving tilt-free translational movement due to symmetrical spring geometries, which lead to undesired tilt and non-linearity, especially when densely packed on substrates, and require multiple posts for electrical addressing, limiting the available space for structural design.
Innovation Solution
The design employs a substrate with a deflectable actuator body connected to at least one post via an asymmetrical spring, allowing the actuator body to move tilt-free during electrostatic, electromagnetic, or magnetic force application, with the actuator body positioned outside the area spanned by the post, utilizing a single anchor point and optimizing spring geometry to prevent stress stiffening and tilt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If symmetrical spring geometries are used in conventional MEMS actuators, then the actuators can be densely packed on substrates, but undesired tilt occurs during deflection
Solution Approach 1:
The patent applies asymmetry by using an asymmetrical spring geometry where the spring is positioned offset from the actuator body's center of mass. Specifically, the spring connects to the actuator body at a point that is not centrally located, creating an asymmetric suspension system that eliminates tilt during deflection while maintaining dense packing capability
2Ease of operation
If multiple posts are used for electrical addressing of actuators, then individual electrical addressing is achieved, but the available space for structural design is limited
Solution Approach 1:
The patent merges the electrical addressing function with the mechanical suspension function by integrating the electrical connection through the existing spring structure. The asymmetrical spring serves both as the mechanical suspension element and as the electrical connection path, eliminating the need for separate posts and freeing up substrate space
3Strength
If springs are mounted on multiple posts, then structural support is provided, but production-induced or thermal stress significantly influences the spring constant
Solution Approach 1:
The patent extracts the spring from the constraint of multiple post mounting locations and relocates it to a single-post asymmetric mounting configuration. This extraction from the conventional multi-post arrangement eliminates the stress accumulation problem while maintaining adequate structural support through the optimized asymmetric spring geometry
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 configuration enables efficient tilt-free translational movement without undesired tilt, even at large deflections, allowing for optimal use of limited space and preventing stress stiffening, suitable for applications like spatial light modulators and micro-mirrors.
Implementation Method 1
a deflectable actuator body connected to at least one post via at least one spring
Implementation Method 2
during electrostatic, electromagnetic or magnetic force application, the actuator body takes a second position starting from a first position
Implementation Method 3
during electrostatic, electromagnetic or magnetic force application, the actuator body takes a second position starting from a first position
Implementation Method 4
during electrostatic, electromagnetic or magnetic force application, the actuator body takes a second position starting from a first position
Data Source
AI summary
Embodiments of the present invention provide an MEMS actuator with a substrate, at least one post attached to the substrate and a deflectable actuator body that is connected to the at least one post via at least one spring, wherein, during electrostatic, electromagnetic or magnetic force application, the actuator body takes a second position starting from a first position by a tilt-free translational movement, wherein the first position and the second position are different, and wherein in a top view of the MEMS actuator the actuator body is arranged outside an area spanned by the at least one post.