MEMS Switch With Stress Gradient Tri-State Actuation
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Solution Overview
Problem
Conventional MEMS switches are typically fabricated in an open state and require power to switch to a closed state, limiting their functionality and efficiency in applications requiring low-cost, high-density switch arrays.
Innovation Solution
A MEMS switch design featuring a switching assembly with a stress gradient that allows it to switch between multiple states without power, utilizing actuation electrodes and contacting members with varying stresses, thicknesses, patterns, and materials to achieve tri-state operation, including a normally closed state and an open state, enabling efficient signal control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If MEMS switches are fabricated in an open state and switched to closed under power, then the switch can be controlled to close when needed, but the switch cannot remain closed without power and requires continuous power to maintain the closed state
Solution Approach 1:
The patent inverts the conventional MEMS switch design by fabricating the switch in a closed state instead of an open state. The switching assembly is pre-configured to be closed without power, and power is applied to open the switch when needed. This inversion resolves the contradiction by allowing the switch to remain closed without continuous power while still providing controllable switching capability.
Solution Approach 2:
The patent changes the stress parameter distribution in the switching assembly by introducing a stress gradient through multiple layers with different stress characteristics. This stress gradient enables the switching assembly to maintain a closed state without power by balancing mechanical forces, while still allowing electrical actuation to open the switch when required.
2Adaptability or versatility
If MEMS switches use a stress gradient design with multiple layers of different materials and thicknesses, then the switch can achieve tri-state operation and remain closed without power, but the device structure becomes more complex
Solution Approach 1:
The patent segments the switching assembly into multiple functional layers including first and second contacting members, first and second actuation electrodes, and intermediate layers with different stress characteristics. This segmentation allows each layer to contribute specifically to achieving tri-state operation while maintaining a systematic and manufacturable structure.
Solution Approach 2:
The patent employs composite material structures with different stress properties, thicknesses, and materials in various layers of the switching assembly. These composite structures create the necessary stress gradient to enable normally closed operation and multi-state switching, achieving enhanced functionality through material composition rather than mechanical complexity.
3Reliability
If MEMS switches are designed with contacting members of varying stresses, thicknesses, patterns, and materials, then the switch can achieve reliable contact and disconnection in multiple states, but the manufacturing process becomes more difficult
Solution Approach 1:
The patent designs the switching assembly with multi-functional layers that serve multiple purposes: the first and second contacting members provide both structural support and electrical contact functions, while the intermediate layers provide both mechanical stress management and electrical isolation. This multi-functionality reduces the need for separate components, simplifying the overall manufacturing process while maintaining reliable contact characteristics.
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 MEMS switch effectively manages signal flows by switching between multiple states, enhancing operational flexibility and reducing power requirements, while providing reliable contact and disconnection mechanisms, thus addressing the limitations of conventional MEMS switches.
Implementation Method 1
The MEMS switch has a stress gradient along the thickness direction of the switching assembly, such that in response to applying no voltage between the first actuation electrode and the second actuation electrode, the switching assembly is in the first closed state and contacts with the first contact
Implementation Method 2
In response to applying a first voltage between the third actuation electrode and the fourth actuation electrode, the switching assembly is driven to deflect such that the switching assembly is in the open state and spaced apart from both the first contact and the second contact
Data Source
AI summary
A MEMS switch includes: a housing, a switching assembly; a first actuation electrode, a first contact, a second contact, and a second actuation electrode. The switching device has a stress gradient along the thickness direction, such that in response to applying no voltage between the first actuation electrode and the second actuation electrode, the switching assembly contacts with the first contact. In response to applying a first voltage between the third actuation electrode and the fourth actuation electrode, the switching assembly is driven to deflect such that the switching assembly is spaced apart from both the first contact and the second contact. In response to applying a second voltage between the third actuation electrode and the fourth actuation electrode, the switching assembly is driven to deflect such that the switching assembly contacts with the second contact. The first voltage is smaller than the third voltage.