Graphene Coated Accelerometer for Charge Dissipation
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Solution Overview
Problem
Acceleration sensors using insulating materials for proof masses and damping plates often accumulate charge, leading to attraction or repulsion forces that interfere with measurements, and existing solutions like metal films are undesirable due to metal-related issues.
Innovation Solution
The use of a graphene layer on nonconductive surfaces within the accelerometer's housing structure, including the proof mass, base, flexure, and double-ended tuning forks, to dissipate static charges and improve thermal conductivity, thereby reducing unwanted forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If insulating materials are used for proof mass and damping plates, then charge accumulation occurs leading to measurement errors, but using conductive metal films to dissipate charge introduces metal stress, thermal expansion, and conductivity issues
Solution Approach 1:
The patent applies a graphene coating layer on the insulating proof mass and damping plates, creating a composite structure that combines the electrical insulation properties of the base material with the charge-dissipating properties of graphene. This resolves the contradiction by providing both measurement precision (through charge dissipation) and reliability (by avoiding metal stress and thermal expansion issues).
Solution Approach 2:
The patent changes the electrical conductivity parameter of the insulating materials by adding a graphene layer. This transforms the materials from purely insulating to having controlled conductive properties, enabling charge dissipation while maintaining the structural and mechanical properties of the original insulating materials.
2Object-affected harmful factors
If metal film is applied to dissipate charge, then charge accumulation is reduced, but metal stress and thermal expansion coefficient mismatches cause additional output errors
Solution Approach 1:
Graphene serves as an intermediary material between the insulating proof mass and the external environment. It provides a pathway for charge dissipation without introducing the problematic mechanical and thermal properties of metals, thus eliminating charge accumulation harmful effects while preserving measurement precision.
3Reliability
If thicker metal layers are used for charge dissipation, then charge dissipation improves, but thermal conductivity variations and stress effects increase
Solution Approach 1:
The patent uses an ultrathin graphene film (typically one atom thick) to provide charge dissipation functionality. This thin film approach achieves effective charge dissipation while minimizing thermal mass and stress effects, allowing rapid thermal equilibrium without the thermal conductivity variations associated with thicker metal layers.
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
Graphene effectively dissipates static charges and enhances thermal conductivity, reducing measurement errors and improving the accuracy and performance of accelerometers by minimizing charge-related errors and achieving rapid thermal equilibrium.
Implementation Method 1
A layer of graphene is located on at least a portion of the nonconductive surfaces within the housing structure... graphene effectively dissipates static charges
Implementation Method 2
graphene enhances thermal conductivity, thereby reducing unwanted forces... achieving rapid thermal equilibrium
Data Source
AI summary
An accelerometer for reducing undesired attraction or repulsion forces between a proof mass and a cover. An exemplary accelerometer includes a proof mass, a base, a flexure that flexibly attaches the proof mass to the base, at least one double-ended tuning fork (DETF) attached at one end to the proof mass and at another end to the base, and a housing structure that encloses the proof mass within a cavity. A layer of graphene is located on at least a portion of the nonconductive surfaces within the housing structure. The nonconductive surfaces include a surface on the proof mass, the housing structure, the base, the flexure, or the DETF. The layer of graphene is attached to a heat sink and/or to an electrical charge dissipation component.