MEMS Scanner Electrode Slope Design for Stable Rotation
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Solution Overview
Problem
Existing MEMS scanners face challenges in achieving stable driving while increasing the driving angle between fixed and driving electrodes, with complex manufacturing processes and high costs, and are limited by structural connections that cause instability and fatigue failures.
Innovation Solution
An MEMS scanner design featuring a lower frame with cavities, upper frames, levers, fixed electrode portions, and a driving electrode portion, where the fixed electrodes are sloped and the driving electrodes are alternately disposed, allowing for increased driving angle and stable rotation without structural interference, using an MEMS process for manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a height difference or slope is introduced between driving electrode and fixed electrode to enable rotational movement, then electrostatic driving is achieved, but manufacturing process becomes complicated requiring additional processes
Solution Approach 1:
The patent introduces a height difference between the driving electrode and fixed electrode by forming the driving electrode on an elevated structure (first substrate) while the fixed electrode remains on the lower second substrate. This dimensional change in the vertical direction enables the necessary slope for rotational movement without complicating the planar manufacturing process.
Solution Approach 2:
The driving electrode is pre-formed on the first substrate at a higher elevation before assembly, creating the initial height difference and slope condition. This preliminary action ensures that when the substrates are assembled, the rotational movement capability is already built into the structure, eliminating the need for additional post-assembly processes.
2Shape
If polymer deposition and heat-deformation is used to incline driving electrode, then initial angle is formed, but manufacturing reproducibility and high speed driving are limited
Solution Approach 1:
The patent replaces the polymer deposition and heat-deformation process with a mechanical structure approach. The driving electrode is formed on an elevated platform or substrate structure that mechanically provides the required inclination angle. This substitution eliminates the limitations of polymer-based methods regarding reproducibility and high-speed driving capability.
3Ease of operation
If rotational spring is plastically deformed using Joule heating to form initial angle, then rotational movement is enabled, but driving angle is limited to unidirectional operation
Solution Approach 1:
The patent segments the electrode structure into multiple independent components: the driving electrode on the first substrate, the fixed electrode on the second substrate, and intermediate support structures. This segmentation allows each component to be optimized independently, enabling bidirectional rotational movement without the constraints of a pre-deformed rotational spring.
4Shape
If additional separate structure is coupled to form initial angle, then driving electrode inclination is achieved, but manufacturing cost and device volume increase
Solution Approach 1:
The patent merges the function of creating the initial angle with the existing substrate and electrode structures. The height difference is achieved by integrating the driving electrode formation process with the substrate structure itself, rather than adding a separate angle-forming component. This merging approach reduces both manufacturing cost and device volume.
5Device complexity
If spring of driving portion and hinge of fixed electrode are structurally connected, then assembly is simplified, but residual stress causes unstable driving and fatigue failures
Solution Approach 1:
The patent extracts or separates the spring component from the fixed electrode hinge structure. The driving portion's spring is made independent from the fixed electrode's hinge, eliminating the structural connection that causes residual stress. This separation allows each component to function independently without transmitting stress to the other, improving driving stability and 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 design enables stable driving with increased driving angle, reduces manufacturing complexity and cost, and prevents fatigue failures by ensuring the driving electrode and fixed electrode portions do not structurally influence each other, allowing for efficient and long-term reliable operation.
Implementation Method 1
sides opposite to the both sides in which the plurality of driving electrodes are disposed are attached to the upper surface of the lower frame using respective rotational springs
Implementation Method 2
In order to allow the electrostatic type driver to have a rotational movement in an electrostatic driving condition, a height difference or a slope is required between the driving electrode and the fixed electrode
Data Source
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AI summary
Provided is an MEMS scanner, which includes a lower frame, a pair of upper frames, a pair of levers, a pair of fixed electrode portions, and a driving electrode portion. The lower frame has cavities formed in an upper surface of the lower frame, and a through-hole is formed between the cavities. The pair of upper frames are attached to the upper surface of the lower frame around the cavities to form an installation space in the central portion between the upper frames. The pair of levers are attached to a bottom surface of the both cavities with the through-hole as a center, and are connected to the pair of upper frames, respectively. One sides of the pair of fixed electrode portions are connected to the respective levers and the other sides thereof are connected to the upper frames, the pair of fixed electrode portions have a plurality of fixed electrodes that can be sloped with respect to the horizontal surface, and the plurality of fixed electrodes are disposed toward the through-hole. The driving electrode portion has a plurality of driving electrodes that are alternately disposed with respect to the fixed electrodes of the pair of fixed electrode portions and are disposed in parallel on the upper surfaces of the respective upper frames at both sides of the driving electrode portion, and sides opposite to sides in which the plurality of driving electrodes are formed are attached to the upper surface of the lower frame using rotational springs, respectively.