Micromirror Device Actuator Gap Design for Power Reduction
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Solution Overview
Problem
In general micromirror devices, the actuator movement is restricted when the mirror portion swings around the first axis, leading to increased power consumption due to the need for high energy to drive the actuator, which results in a decrease in the Q value during driving.
Innovation Solution
The micromirror device incorporates a unique design where the mirror portion is supported by a first support portion on the first axis and a second support portion on the second axis, with a driving portion surrounding the movable portion and having a gap with the second support portion. This configuration ensures that the movement of the actuator is less restricted, allowing for efficient two-dimensional driving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the actuator is directly connected to the fixed frame on the second axis, then the structure is simple and easy to manufacture, but the actuator movement is greatly restricted when the mirror portion swings around the first axis, causing increased power consumption
Solution Approach 1:
The device is divided into separate functional modules: the second support portion that swingably supports the movable portion around the second axis, and the driving portion that surrounds the movable portion. This segmentation allows the actuator to move more freely while maintaining structural simplicity, resolving the contradiction between ease of manufacture and power consumption.
Solution Approach 2:
The coupling portion acts as an intermediary between the second support portion and the driving portion. It transmits motion while allowing the actuator to move with less restriction during first-axis swinging, thereby reducing power consumption without complicating the overall structure.
2Device complexity
If the actuator is directly connected to the fixed frame, then the structural complexity is low, but the Q value decreases due to high energy requirement for driving the actuator
Solution Approach 1:
The second support portion is designed to swingably support the movable portion around the second axis, creating a dynamic structure that adapts during operation. This dynamic configuration reduces the energy required to drive the actuator while maintaining low structural complexity, thereby preserving the Q value.
Solution Approach 2:
The driving portion surrounds the movable portion and the actuator is positioned to move in a different spatial arrangement. This dimensional reconfiguration allows the actuator to operate with less restriction without increasing overall device complexity, thus maintaining high Q value.
3Length of moving object
If the second support portion has large length L, then the mirror portion can swing with larger deflection angle, but the distance A from the intersection to the end part increases, restricting actuator movement
Solution Approach 1:
The second support portion is pre-configured with an optimized length L and positioned distance A from the intersection, allowing the mirror portion to achieve the required deflection angle while leaving sufficient space for the actuator to move freely. This preliminary optimization resolves the contradiction between deflection angle and actuator movement.
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 described configuration reduces power consumption during two-dimensional driving by minimizing the energy required to drive the actuator, thereby maintaining a higher Q value and enhancing the stability and efficiency of the optical scanning device.
Implementation Method 1
a piezoelectric drive method using deformation of a piezoelectric body is promising since the generated torque is higher than that in other methods
Data Source
AI summary
The micromirror device includes: a mirror portion; a first support portion that swingably supports the mirror portion around a first axis; a pair of movable frames that face each other across the first axis; a second support portion that swingably supports a movable portion around a second axis; a driving portion that surrounds the movable portion and has a gap with the second support portion on the second axis; a coupling portion that couples the second support portion and the driving portion; and a fixed frame, in which, in a state where the mirror portion rotates around the first axis and an absolute value of a rotation angle is larger than 0 degrees, assuming that, in a plane orthogonal to the first axis and including the second axis, a distance between an intersection between the second axis and a straight line located on a surface of the second support portion and including each end point of the second support portion and an end part of the second support portion on a mirror portion side in a stationary state is denoted by A, and a total length of the second support portion in a direction of the second axis is denoted by L, a relationship of A/L≤⅔ is satisfied.