MEMS Shutter Ribs with Gaps for Stress Relief
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Solution Overview
Problem
Microelectromechanical systems (MEMS) structures, such as shutters in displays, tend to deform globally due to stress, which affects manufacturability and functionality, as existing designs lack effective stress relief mechanisms.
Innovation Solution
Incorporating a suspended planar body with a depression and a substantially horizontal gap in MEMS assemblies, which allows for localized deformation and stress relief, thereby confining stress impacts to specific regions rather than causing global deformations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rib is added to stiffen the shutter, then the shutter becomes stiffer and more stable, but stress-induced global deformation increases
Solution Approach 1:
The continuous rib structure is segmented by introducing gaps at strategic locations. This segmentation allows the rib to maintain overall stiffness while creating localized flexibility zones that prevent stress from propagating across the entire shutter, thereby reducing global deformation.
Solution Approach 2:
The rib structure transitions from uniform to non-uniform by introducing gaps only at specific locations where stress concentration occurs. This local modification provides stress relief precisely where needed while maintaining structural integrity and stiffness in other critical regions of the shutter.
2Strength
If the shutter is made stiffer to reduce deformation, then structural integrity improves, but manufacturability deteriorates due to stress-induced warping
Solution Approach 1:
By segmenting the rib structure with gaps, the patent reduces cumulative stress that would otherwise cause warping during manufacturing. The gaps act as stress break points, allowing the stiffened shutter to be manufactured without severe warping issues while maintaining structural integrity.
Solution Approach 2:
The patent modifies the geometric parameters of the rib structure by introducing gaps with specific dimensions (e.g., 5-20 micrometers). This parameter change alters the stress distribution characteristics, enabling the shutter to achieve the desired structural integrity while remaining manufacturable by reducing stress-induced warping.
3Shape
If gaps are introduced to relieve stress, then global deformation is reduced, but the structural stiffness decreases
Solution Approach 1:
The rib is segmented with gaps positioned strategically rather than uniformly distributed. This selective segmentation creates localized stress relief zones that prevent global deformation while maintaining overall structural stiffness through the continuous portions of the rib between gaps.
Solution Approach 2:
The gap introduction is applied locally at specific high-stress regions rather than uniformly across the entire rib structure. This localized approach provides stress relief where most needed while preserving structural stiffness in other regions, achieving a balance between deformation control and structural strength.
Data Source
AI summary
This disclosure provides systems, methods and apparatus for an electromechanical systems (EMS) assembly. The EMS assembly includes a substrate, an anchor disposed on the substrate, and a suspended planar body supported over the substrate by the anchor. The suspended planar body includes at least one depression extending out of a plane of the suspended planar body and protruding towards the substrate. The suspended planar body also includes a substantially horizontal portion corresponding to a gap in the at least one depression. An extent of the gap is up to 20% of a length of the suspended planar body.