Polymer Linear Actuator Asymmetric Thermal Expansion MEMS
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional MEMS type linear actuators using electrostatic forces have high operation voltage and relatively small driving force, and existing polymer-based actuators can only rotate, not move linearly.
Innovation Solution
A polymer linear actuator design that utilizes V-type moving units or bar-type connection parts with silicon drive members and a resistor part for thermal expansion and contraction to convert rotational motion into linear motion, allowing for strong driving force and precise linear movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If electrostatic MEMS actuators are used, then high response speed is achieved, but operation voltage becomes very high and driving force becomes relatively small
Solution Approach 1:
The patent applies thermal expansion of polymer materials to generate linear motion. The polymer layer expands when heated by a heating element, causing the moving part to move linearly along the thermal expansion direction. This thermal actuation mechanism provides both sufficient driving force and acceptable response speed while operating at lower voltages compared to electrostatic actuators.
2Force
If polymer layers are used for actuation, then strong driving force is achieved, but only rotational motion is possible not linear motion
Solution Approach 1:
The patent introduces asymmetry in the polymer layer structure by creating a trapezoidal configuration where the polymer layer has different lengths on opposite sides. This asymmetric geometry converts the isotropic thermal expansion of the polymer into unidirectional linear motion. When the polymer expands uniformly due to heating, the asymmetric shape causes differential expansion in different directions, resulting in net linear displacement rather than rotation.
Solution Approach 2:
The patent transitions from rotational actuation to linear actuation by changing the geometric configuration of the polymer layer. Instead of using a symmetric structure that rotates upon thermal expansion, the asymmetric trapezoidal design directs the expansion along a linear axis, effectively converting thermal energy into linear mechanical work in a different dimensional mode.
3Volume of moving object
If conventional electrostatic actuators are used, then micro size and reproducibility are achieved, but displacement becomes relatively small
Solution Approach 1:
The patent changes the actuation parameter from electrostatic field to thermal field, allowing for larger displacement. The polymer layer's thermal expansion coefficient provides significant dimensional change when heated, enabling displacement much larger than what electrostatic actuators can achieve at the same micro scale. The heating element can be controlled to provide incremental expansion for precise yet large-range positioning.
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 polymer linear actuator achieves efficient linear motion with a strong driving force, overcoming the limitations of conventional MEMS actuators by utilizing thermal expansion and contraction, enabling precise control and increased displacement.
Implementation Method 1
the polymer layer 9 expands so that the moving part 7 rotates in the left side along an arrow direction due to the contraction difference between the upper and lower sides
Data Source
AI summary
A polymer linear actuator for a micro electro mechanical system (MEMS) and a micro manipulator for a measurement device of cranial nerve signal using the same are provided. The polymer linear actuator has first and second bodies positioned spaced apart to a distance from each other, and one or more pairs of V-type moving units connecting the first and second bodies together, wherein the moving units in pair are opposed to each other to convert a rotation motion of the respective moving units into a linear motion, thereby causing the first and second bodies to move linearly.