Micromechanical Arm Array Structure for Shock-Resistant MEMS Actuators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
MEMS actuators, particularly those used in optical image capture devices, are prone to breakage due to impacts and shocks, such as drops from a large height, due to insufficient stability and strength of their micromechanical arm arrays.
Innovation Solution
The micromechanical arm arrays are designed with two arrays of fingers, one made of piezoelectric material and the other of electrically conductive material, interconnected by micro-springs, which enhance stability and strength, featuring a ratio of piezoelectric to conductive fingers ranging from 1:1 to 10:1, and include a metal cap and horizontal micro-springs for vibration isolation and damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the micromechanical arm array uses a simple single-material structure, then the device complexity is low, but the strength and stability are insufficient leading to breakage under impacts
Solution Approach 1:
The patent applies composite materials by combining piezoelectric material and electrically conductive material in a multi-layer finger structure. The piezoelectric layer provides actuation functionality while the conductive layer enhances mechanical strength and stability, creating a composite structure that resolves the contradiction between strength and device complexity.
Solution Approach 2:
The patent segments the finger structure into multiple functional layers (piezoelectric layer, conductive layer, and optional intermediate layers) rather than using a single monolithic structure. This segmentation allows each layer to contribute specific properties, improving overall strength without significantly increasing perceived device complexity.
2Stability of the object's composition
If the micromechanical arm array uses a simple single-material structure, then the manufacturing process is simple, but the stability is insufficient leading to breakage under impacts
Solution Approach 1:
The composite material structure with piezoelectric and conductive layers provides enhanced stability through material property complementarity. The conductive layer acts as a structural reinforcement that prevents breakage under impact, while the piezoelectric layer maintains actuation functionality, achieving improved stability with manageable manufacturing complexity.
Solution Approach 2:
The patent changes material parameters by selecting specific piezoelectric materials (e.g., PZT, BTO) and conductive materials (e.g., polysilicon, metal) with complementary properties. This parameter optimization ensures the composite structure achieves required stability while remaining compatible with standard MEMS manufacturing processes.
3Reliability
If the micromechanical arm array uses a simple structure without vibration isolation, then the device complexity is low, but the micro-springs are prone to breakage under shocks
Solution Approach 1:
The patent implements beforehand cushioning by incorporating vibration isolation structures and damping elements into the micromechanical arm array design. These features are built into the structure in advance to protect the micro-springs from shock-induced breakage, improving reliability without significantly increasing device complexity.
Solution Approach 2:
The patent introduces intermediary structures such as damping layers and vibration isolation elements that mediate between the external shock environment and the sensitive micro-spring components. These intermediaries absorb and dissipate impact energy, protecting the micro-springs from direct shock loads and improving overall system reliability.
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 improved design enhances the lifetime of the micro-springs and increases the stability and strength of the micromechanical arm arrays, reducing the likelihood of breakage under external shocks.
Implementation Method 1
The micromechanical arm array includes a first array of fingers formed from a piezoelectric material
Implementation Method 2
interconnected by micro-springs, which enhance stability and strength, featuring a ratio of piezoelectric to conductive fingers ranging from 1:1 to 10:1, and include a metal cap and horizontal micro-springs for vibration isolation and damping
Data Source
AI summary
A micro-electromechanical system (MEMS) structure is useful as an actuator for moving an image sensor for optical image stabilization. The MEMS actuator includes one or more micromechanical arm arrays. Each arm array includes a first array of spaced-apart fingers formed from a piezoelectric material, and a second array of spaced-apart fingers formed from an electrically conductive material. The distal ends of the first array of fingers and the distal ends of the second array of fingers are interposed between each other. Micro-springs connect the interposed distal ends of each set of adjacent fingers together. A metal cap is present above the distal ends of the first array of fingers and the distal ends of the second array of fingers. Micro-springs connect the metal cap to the distal end of each finger of the first array of fingers. This structure has increased stability and strength.