MEMS Out-of-Plane Hinge Segmented Beams Stress Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Microelectromechanical systems (MEMS) face structural deformation due to internal stresses, particularly in out-of-plane hinges, which affect the accuracy of sensors and actuators by causing tilting and misalignment, complicating the production process and reducing the range of stress measurement.
Innovation Solution
An out-of-plane hinge design featuring a pair of parallel bending beams connected in series, where one beam is connected to the support and the other to the movable part, allowing uniform or non-uniform stress-induced deformations to cancel each other out, reducing structural deformation and maintaining stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bending beams are formed in the epitaxial layer to stiffen the joint in the X direction, then the joint stiffness in X direction is improved, but the joint stiffness in the out-of-plane direction increases and the mass tilts due to stress release
Solution Approach 1:
The bending beam is divided into multiple segments (first bending beam, second bending beam, third bending beam) connected in series. Each segment can independently deform under stress, allowing the beam to accommodate stress-induced deformation while maintaining overall structural integrity and preventing mass tilting.
Solution Approach 2:
The patent changes the structural parameters of the bending beam by introducing multiple segments with different orientations. The first bending beam is parallel to the X axis, the second is parallel to the Y axis, and the third is parallel to the X axis again. This parameter variation allows the structure to compensate for stress-induced deformations.
2Length of moving object
If the thickness of bending beams is reduced to decrease their effect on stiffness in the Z direction, then the out-of-plane movement freedom is improved, but the joint stiffness in the X direction is reduced
Solution Approach 1:
The bending beam is segmented into multiple sections that can deform independently. This segmentation allows the beam to maintain adequate stiffness in the X direction while permitting necessary out-of-plane movement, as each segment can accommodate deformation without compromising overall structural integrity.
Solution Approach 2:
The bending beam employs a composite structure with multiple segments having different orientations and potentially different material properties. This composite approach enables the beam to exhibit anisotropic mechanical behavior, being stiffer in the X direction while remaining more compliant in the out-of-plane direction.
3Ease of manufacture
If internal stresses are released during structure production, then the manufacturing process is simplified, but structural deformation occurs causing mass tilting and gauge misalignment
Solution Approach 1:
The patent applies preliminary anti-action by designing the bending beam with a specific segmented structure that anticipates and counteracts the deformation caused by stress release. The beam's geometry and segmentation are pre-configured to compensate for the expected stress-induced tilting, maintaining alignment precision despite stress release during manufacturing.
4Ease of manufacture
If the mass is inclined due to stress release, then the production process is simplified, but the range of stress measurement is reduced and maximum admissible stress may be exceeded
Solution Approach 1:
The segmented bending beam structure is designed in advance to counteract the inclination caused by stress release. By pre-configuring the beam's geometry and segmentation, the structure maintains proper mass orientation, preserving the full range of stress measurement capability and preventing excessive stress conditions.
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
This design minimizes structural deformation, maintains stability, and reduces the impact of internal stresses on the hinge, enhancing the accuracy and reliability of MEMS sensors and actuators by ensuring the movable part remains perpendicular to the Z-axis, thus improving measurement range and production simplicity.
Implementation Method 1
When the layer is grown by epitaxy, stresses are generated in the layer. These stresses can be due to doping. For example, boron atoms are smaller than silicon atoms and induce compressive stress in the silicon crystal lattice.
Implementation Method 2
When the structure is released by etching, these stresses in all layers are at least partially released. This stress release generates a new balance of forces and moments that can lead to deformation of the structure.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A hinge for a micromechanical and/or nanomechanical structure comprising a support (2), a movable part (M) in an out-of-plane direction (Z), said hinge allowing out-of-plane movement of the movable part (M), the hinge comprising two torsion beams (6) extending along the axis of rotation (Y1) of the hinge, two flexural elements (E1) mechanically connecting the movable part (M) and the support (2) and comprising at least one pair of a first (12.1, 12.1) and a second (12.2) beam parallel to each other and extending in a plane perpendicular to the axis of rotation (Y1), the first beam (12.1) being connected to the support (2) and the second beam (12.2) being connected to the movable part (M), the first and second beams being connected to each other by a first connecting element at one longitudinal end, the two beams extending in the same direction starting from the first connecting element.