Tapered DLC Impact Element for Static Discharge in MEMS Sensors
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Solution Overview
Problem
Conventional microelectromechanical sensors face challenges in efficiently managing static electricity buildup due to tribocharging, which affects the sensitivity and offset of the sensor devices, particularly in structures with planar movable masses undergoing out-of-plane motion, where DLC coatings while resistant to wear, do not consistently prevent static electricity issues.
Innovation Solution
A sensor device with an impact element featuring a bulk material inner part tapered to be lower at the edges and coated with a diamond-like carbon (DLC) layer that extends beyond the edges, improving conductivity and effectively discharging static electricity, manufactured using directed energy beam plasma-enhanced chemical vapor deposition processes to optimize DLC layer conductivity on sloped sidewalls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a planar movable mass structure is used for out-of-plane motion, then the sensor device achieves compact design and simple manufacturing, but static electricity buildup occurs due to tribocharging at contact points
Solution Approach 1:
The impact element is designed with non-uniform geometry where the cross-sectional form is larger at the base than at the top, creating a tapered shape. This local variation in geometry increases the surface area at contact regions, improving conductivity and static discharge capability specifically at the edges where tribocharging occurs, without changing the overall simple structure of the sensor device
Solution Approach 2:
The impact element combines bulk material with a diamond-like carbon (DLC) coating layer. The DLC coating provides enhanced wear resistance and improved electrical conductivity at the contact surfaces, allowing effective discharge of static electricity while maintaining the mechanical robustness of the bulk material structure
2Strength
If DLC coating is applied to the impact element, then wear resistance is improved, but static electricity discharge is insufficient with conventional planar structures
Solution Approach 1:
The DLC coating is applied to the tapered impact element where the coating on sloped sidewalls benefits from the geometric configuration. The tapered shape creates larger contact area at the edges, and when coated with DLC, this geometry optimizes the conductivity of the coating layer, enabling effective static electricity discharge while maintaining wear resistance
Solution Approach 2:
The impact element geometry is changed from a conventional rectangular or planar shape to a tapered form where the cross-sectional area varies along the height. This parameter change in geometry transforms the conductivity distribution of the DLC coating, creating optimal conditions for static electricity discharge at the contact regions
3Strength
If the impact element cross-section is enlarged at the base, then mechanical robustness is improved, but manufacturing complexity increases
Solution Approach 1:
The impact element features a tapered shape with curved or sloped sidewalls where the cross-sectional form is larger at the base than at the top. This curved geometry provides enhanced mechanical robustness and stability during impacts, while still being manufacturable using standard microfabrication techniques such as anisotropic etching or deposition processes that can create tapered structures
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 significantly reduces static electricity buildup and enhances the mechanical robustness of the impact element, ensuring consistent performance and reliability by improving DLC conductivity and distributing impact forces effectively.
Implementation Method 1
the tapered form of the impact element improves conductivity of the DLC coating over the outer edges such that discharge of static buildup in the impact element center part contact area is significantly improved
Implementation Method 2
manufactured using directed energy beam plasma-enhanced chemical vapor deposition processes to optimize DLC layer conductivity on sloped sidewalls
Implementation Method 3
The buildup is mainly generated to the protrusions through tribocharging. The triboelectic effect is a type of contact electrification in which certain materials become electrically charged after coming into contact with a different material
Data Source
AI summary
A sensor device and a method for manufacturing the sensor device. The sensor device is equipped with an impact element that includes an inner part of dielectric bulk material and an outer part of diamond-like coating material. The inner part is made to be lower at the edges than in the middle, and the outer part is formed of a diamond-like coating layer that covers the inner part. The DLC coated impact element is mechanically more robust than the rectangular prior art structures. Furthermore, the tapered form of the impact element improves conductivity of the DLC coating such that discharge of static buildup in the impact element is effectively enabled.