Micromirror Slit Support Structure for Large Deflection Scanning
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Solution Overview
Problem
Micromirror devices experience structural destruction due to stress concentration when attempting to achieve large deflection angles, necessitating larger structures that compromise size and deflection capabilities.
Innovation Solution
A mirror device design featuring a mirror portion supported by first and second support portions, connected to a driving unit with connecting portions having slits and a fixed frame with beam portions, which distributes stress and allows for a large deflection angle without increasing size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the structure of each part is increased to relieve stress concentration, then stress distribution is improved, but the device size increases
Solution Approach 1:
The patent employs a thin film structure with integrated stress relief features rather than thickening components. The connecting portion with a slit acts as a flexible element that distributes stress without requiring increased overall device volume, maintaining compactness while improving stress distribution.
Solution Approach 2:
The patent changes the geometric parameters of the connecting portion by introducing a slit, which fundamentally alters the stress distribution pattern. This parameter modification allows stress to be dispersed through the slit structure without increasing the overall dimensions of the device parts.
2Force
If the driving range is increased to achieve larger deflection angle, then deflection capability is improved, but stress concentration increases
Solution Approach 1:
The patent converts the potentially harmful stress concentration into a beneficial stress distribution pattern by strategically placing a slit in the connecting portion. The slit, which might seem to weaken the structure, actually serves to distribute the stress generated during large deflection operations, enabling greater deflection angles without proportional increases in stress concentration.
Solution Approach 2:
The thin film connecting portion with an integrated slit provides flexibility that accommodates large deflection angles. The slit creates a compliant structure that can undergo larger deformations without generating excessive stress concentrations, thus enabling improved deflection capability.
3Area of stationary object
If the deflection angle is increased to improve scanning area, then scanning capability is improved, but structural destruction risk increases
Solution Approach 1:
The slit in the connecting portion converts the harmful effect of stress concentration during large deflection into a beneficial stress distribution mechanism. This allows the mirror portion to achieve larger deflection angles for expanded scanning area while the slit prevents stress from concentrating at critical points, thereby maintaining structural integrity.
Solution Approach 2:
The connecting portion is segmented by introducing a slit, which divides the continuous material into regions that can independently deform. This segmentation allows the structure to accommodate large deflection angles without creating stress concentration points that would lead to structural failure, thus improving reliability during high-deflection operation.
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 suppresses structural destruction and enables a large deflection angle while maintaining a compact size, utilizing piezoelectric actuators for biaxial scanning in optical scanning devices.
Implementation Method 1
a piezoelectric drive method using deformation of a piezoelectric material is promising since the generated torque is higher than that in other methods
Implementation Method 2
a mirror portion that has a reflecting surface for reflecting incident light
Data Source
AI summary
A mirror device includes a mirror portion, a pair of first support portions, a driving unit, a fixed frame that is disposed to surround the driving unit, and a pair of connecting portions that connect the driving unit to the fixed frame, in which each of the pair of connecting portions has a slit, and the slit is disposed at a position where the slit is line-symmetric with respect to a first axis or a second axis intersecting the first axis as a symmetry axis.