Asymmetrical Capacitive Accelerometer for Seismic Sensing
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Solution Overview
Problem
Existing acceleration sensors for seismic prospecting face challenges in achieving high sensitivity and low power consumption while operating in miniaturized devices, with issues related to bidirectional actuation and capacitance variations affecting their performance.
Innovation Solution
The design incorporates a mass body with asymmetrical movable portions and strategically arranged AC and DC servo capacitive elements, allowing for bidirectional servo control and reduced capacitance variations, enabling high sensitivity and low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a capacitive accelerometer with seesaw structure is used, then sensitivity is improved, but power consumption increases
Solution Approach 1:
The movable portion is divided into first and second movable portions with different areas, creating asymmetrical capacitance distribution. This segmentation allows the patent to achieve high sensitivity through the seesaw structure while controlling power consumption by optimizing the area ratio between the two portions
Solution Approach 2:
The patent introduces asymmetrical movable portions with different areas to create unbalanced capacitance distribution. This asymmetry enables the accelerometer to achieve high sensitivity while reducing the need for large actuation electrodes, thereby lowering power consumption requirements
2Measurement precision
If actuation electrodes are arranged far from the rotation shaft, then sensitivity is improved, but device complexity increases
Solution Approach 1:
The patent applies different area characteristics to different regions of the movable portion. The first and second movable portions have different areas to create local capacitance variations, enabling high sensitivity without requiring actuation electrodes far from the rotation shaft, thus reducing device complexity
3Manufacturing precision
If symmetrical sensing electrodes are used, then manufacturing precision is improved, but bidirectional actuation capability deteriorates
Solution Approach 1:
The patent deliberately introduces asymmetry in the movable portions' areas to enable bidirectional actuation capability. This asymmetry allows the accelerometer to respond effectively in both directions while maintaining manufacturing precision through controlled capacitance distribution
Solution Approach 2:
The patent creates a dynamic capacitance distribution through the asymmetrical movable portions, enabling the system to adapt to bidirectional actuation requirements. The different areas of the movable portions create dynamic capacitance variations that support versatile directional response
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
This configuration enhances the sensitivity and reduces power consumption of the acceleration sensor, facilitating its use in miniaturized devices and improving the accuracy of seismic prospecting systems.
Implementation Method 1
In order to provide an equilibrium force in which the mass body is controlled to a certain position, an AC voltage is applied to the first AC servo control electrode and the second AC servo control electrode
Implementation Method 2
a DC voltage is applied to the DC servo control electrode
Implementation Method 3
a first AC servo capacitive element is formed by the first movable portion and the first AC servo control electrode, a second AC servo capacitive element is formed by the second movable portion and the second AC servo control electrode
Data Source
AI summary
Provided are acceleration sensor, geophone and seismic prospecting system with high sensitivity and low power consumption. The acceleration sensor includes a mass body displaceable with respect to a rotation shaft. The acceleration sensor includes a first AC servo control facing a first symmetrical region of the first movable portion, a second AC servo control electrode facing a second symmetrical region of the second movable portion, and a DC servo control electrode facing an asymmetrical region of the second movable portion. A first AC servo capacitive element is formed by the first movable portion and the first AC servo control electrode, a second AC servo capacitive element is formed by the second movable portion and the second AC servo control electrode, and a DC servo capacitive element is formed by the second movable portion and the DC servo control electrode.