Electrostatic Drive Switch Dual Contact Reliability
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Solution Overview
Problem
MEMS switches face reliability issues and high contact resistance in high-voltage and high-current switching conditions, leading to thermal damage and arc occurrence due to joule's heat and high electric fields.
Innovation Solution
An electrostatic drive switch employing a dual contact method, where initial contact is made with a high-hardness material for reliability and subsequent contact with a low-hardness material to maximize contact force and reduce resistance, using a plate-shaped source electrode with elastic parts to manage the switching of high-current and high-voltage signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single contact material is used in MEMS switches, then the structure is simple, but reliability deteriorates in high-voltage and high-current conditions due to welding and arc occurrence
Solution Approach 1:
The contact structure is segmented into two distinct materials: a first contact material (e.g., platinum) for high-voltage switching to prevent arc and welding, and a second contact material (e.g., gold) for low-resistance high-current conduction. This segmentation allows each material to perform its specialized function, resolving the contradiction between reliability and structural simplicity.
Solution Approach 2:
The patent employs composite contact structures where different materials are combined in a single contact interface. The first contact material provides arc resistance for high-voltage operation, while the second contact material provides low contact resistance for high-current capability, achieving both reliability and electrical performance through material composition.
2Reliability
If a high-hardness material is used for high-voltage switching, then arc and welding are prevented, but contact resistance increases due to reduced contact force
Solution Approach 1:
The contact interface is segmented into two materials with complementary properties: the first contact material (high hardness) handles high-voltage switching to prevent arc and welding, while the second contact material (softer, more conductive) establishes firm contact to minimize contact resistance and maximize contact force.
Solution Approach 2:
Different local regions of the contact interface have different material properties optimized for their specific functions. The first contact material region provides arc resistance where high-voltage breakdown occurs, while the second contact material region provides low resistance where current conduction is critical, achieving local optimization of both reliability and electrical performance.
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 enhances reliability and contact force while minimizing contact resistance, enabling effective switching of high-current and high-voltage signals by sequentially engaging materials with different hardness levels, thereby overcoming the limitations of existing MEMS switches.
Implementation Method 1
an electrostatic drive switch includes: a source plate to which a voltage for driving the electrostatic drive switch is applied
Implementation Method 2
the source plate includes a source electrode and an elastic part connected to the source electrode
Data Source
AI summary
Provided is an electrostatic drive switch, which includes a source plate to which a voltage for driving the electrostatic drive switch is applied and a drain electrode spaced apart from the source plate. The source plate includes a source electrode and an elastic part connected to the source electrode, and a first material and a second material having lower hardness than the first material are provided on the source electrode. When the source electrode and the drain electrode are electrically connected to each other by the voltage, the second material is brought into contact with the drain electrode by the elastic part after the first material is brought into contact with the drain electrode by the elastic part.