Out-of-Plane MEMS Hinge Layout to Prevent Tilt From Stress Release
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Solution Overview
Problem
Microelectromechanical systems (MEMS) face structural deformation and sensitivity to internal stresses due to stress release during manufacturing, which affects the accuracy and range of measurement, particularly in out-of-plane displacements, leading to tilting and misalignment of movable parts.
Innovation Solution
An out-of-plane hinge design featuring combined bending beams that self-compensate internal stresses, with pairs of bending elements arranged to neutralize stress effects, and torsion elements that manage torsional stresses, ensuring minimal deformation and maintaining the movable part's position relative to the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If internal stresses are released during manufacturing, then the manufacturing process is simplified, but structural deformation occurs
Solution Approach 1:
The invention converts the harmful effect of internal stress release into a beneficial self-compensation mechanism. The specific geometric configuration of the bending beam segments is designed so that when internal stresses are released during manufacturing, the resulting deformations in different segments counterbalance each other, automatically compensating for potential structural deviations without requiring additional manufacturing steps.
2Stress or pressure
If the mass is tilted due to stress release, then the stress in gauges increases, but the range of variation of stress decreases
Solution Approach 1:
The bending beam structure is designed with preliminary anti-action built into its geometry. The arrangement of beam segments creates pre-compensating forces that counteract the tilting effect before it significantly impacts the gauge measurements. This preliminary counter-action prevents excessive stress concentration and maintains a broader operational range for stress variation.
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 solution reduces the impact of internal stresses on the structure, maintaining the movable part's rest position centered between stops, minimizing strain on strain gauges, and preventing tilting, thus enhancing measurement accuracy and range without complicating the production process.
Implementation Method 1
An out-of-plane hinge for a micro and/or nanomechanical structure with reduced sensitivity to internal stresses
Implementation Method 2
The structure also comprises two piezoresistive gauges 1010 making it possible to measure the displacement of the mass
Implementation Method 3
The hinge connects an edge of the mass to the support, and comprises two beams 1006 intended to be stressed in torsion
Implementation Method 4
two beams 1008 intended to be stressed in bending and orthogonal to the axis of rotation
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Hinge between a support (2) and a movable part (M) in an out-of-plane direction (Z) of a microelectromechanical structure, the hinge (4) comprising two torsion beams (6), two bending elements (E1) connecting the movable part (M) and the support (2), each comprising two beams (12.1, 12.2) extending perpendicularly to the axis of rotation (Y1), each beam (12.1, 12.2) being connected to the support (2) by a first end (12.11, 12.21) and to the movable part (M) by a second end (12.12, 12.22), the first ends (12.11, 12.21) and the second ends (12.12, 12.22) of the beams (12.1, 12.2) being arranged relative to each other such that the orientation of the first end (12.11) towards the second end (12.12) of a beam (12.1) is opposite to the orientation of the first end (12.21) towards the second end (12.22) of the other beam (12.2).