Discretely Controlled Micromirror with Stepper Plate Actuation
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Solution Overview
Problem
Existing micromirror control systems face limitations in achieving multiple degrees of freedom with low driving voltage and simple activation mechanisms, as they often require complex analog control and are prone to the snap-down phenomenon, especially when using continuous displacement actuated by electrostatic force.
Innovation Solution
A discretely controlled micromirror system with multiple degrees of freedom rotation and translation, utilizing stepper plates with pre-programmed motions actuated by electrostatic or electromagnetic forces, and supported by various geometrically coupled supports to achieve precise motion control with reduced stiction and increased motion range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous displacement control is used with electrostatic force, then fine motion control is achieved, but the snap-down phenomenon occurs limiting motion range
Solution Approach 1:
The continuous motion range is segmented into discrete positional levels. The micromirror can be positioned at multiple predetermined locations along the translation axis, with each level providing stable equilibrium. This segmentation prevents the snap-down phenomenon by limiting travel between stable points, while still achieving multi-degree-of-freedom motion capability.
Solution Approach 2:
The system uses periodic electrostatic actuation to achieve discrete positional changes. By applying voltage sequences to electrode pairs, the micromirror is moved between predetermined positions in a controlled manner, avoiding continuous displacement that causes snap-down while maintaining precise positioning capability.
2Measurement precision
If analog mode control is used for continuous displacement, then fine voltage control is achieved, but the control system becomes complex and difficult to combine with semiconductor electronics
Solution Approach 1:
The system replaces complex analog voltage control with simpler digital or discrete voltage switching. Instead of requiring fine analog voltage adjustment, the system uses discrete voltage levels applied to electrode pairs, which can be easily implemented with standard semiconductor electronics and digital control circuits.
Solution Approach 2:
The control approach changes from continuous analog voltage parameters to discrete voltage states. Each electrode pair is controlled by switching between defined voltage levels, transforming the control problem from continuous parameter management to discrete state control, which is more compatible with digital electronics.
3Ease of operation
If high driving voltage is used for continuous displacement control, then motion control is achieved, but compatibility with IC components is reduced
Solution Approach 1:
The total voltage requirement is segmented across multiple electrode pairs rather than requiring a single high voltage. Each electrode pair operates at lower voltage levels, distributing the total actuation voltage across series-connected electrode pairs, thereby reducing the voltage stress on individual components and improving IC compatibility.
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 system provides fine and simple control of micromirror motion with low driving voltage, enabling multiple motions and increased stability, while avoiding the snap-down phenomenon and compatibility with semiconductor electronics.
Implementation Method 1
Most of these micromirrors have been controlled to have continuous displacements, which are determined at the equilibrium between electrostatic force and elastic force.
Implementation Method 2
utilizing stepper plates with pre-programmed motions actuated by electrostatic or electromagnetic forces
Data Source
AI summary
A discretely controlled micromirror device provides multiple motions of a micromirror using stepper plate and micromirror bottom support. The discretely controlled micromirror device can be controlled in a low driving voltage. Also, simple motion control is applied by digital controlling and only single voltage is needed for driving the micromirror motion.