Dual Movable Electrode Layout for Low-Loss Capacitive Sensing
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Solution Overview
Problem
Capacitive detection microphones suffer from energy losses due to deformation of the piston, transmission device, and frame, leading to reduced sensitivity and resonance frequency, and the pull-in phenomenon limits the bias voltage.
Innovation Solution
An electromechanical system with a frame, a first movable element, and capacitive measurement means featuring a first movable electrode and a second movable electrode, connected via rotatable transmission devices with pivot hinges, reducing energy loss and enhancing sensitivity and resonance frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the piston, transmission device, and frame are reinforced to reduce deformation, then energy loss is reduced, but the mass of movable parts increases and resonance frequency decreases
Solution Approach 1:
The invention divides the movable element into two separate movable elements instead of using a single reinforced piston. This segmentation allows each element to be lighter while the system as a whole achieves reduced energy loss through minimized deformation of individual components.
Solution Approach 2:
The invention changes the structural parameters by using two separate movable elements with their own transmission devices rather than one reinforced element. This parameter change reduces the mass of individual movable parts while maintaining or improving energy efficiency through reduced deformation.
2Loss of energy
If the piston, transmission device, and frame are reinforced to reduce deformation, then energy loss is reduced, but sensitivity and resonance frequency are reduced
Solution Approach 1:
Dividing the system into two movable elements with separate transmission devices allows each element to remain lightweight and highly responsive, maintaining sensitivity while reducing energy loss through minimized deformation of individual components.
Solution Approach 2:
The invention uses two independent movable elements that can dynamically respond to acoustic pressure, maintaining high sensitivity. The separate transmission devices allow for optimized dynamic characteristics that reduce energy loss without compromising responsiveness.
3Device complexity
If a single movable element is used, then the design is simpler, but energy loss due to deformation is higher
Solution Approach 1:
The invention segments the movable element into two separate elements, each with its own transmission device. This segmentation reduces energy loss by minimizing deformation in each individual component, while the overall design remains relatively simple and manufacturable.
4Measurement precision
If the bias voltage is increased to improve sensitivity, then the pull-in phenomenon occurs
Solution Approach 1:
By using two separate movable elements with capacitive detection, the system can distribute the electrostatic forces and reduce the risk of pull-in phenomenon while maintaining high sensitivity. The segmentation allows for better control of electric fields and reduced stress on individual components.
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 system achieves improved sensitivity and resonance frequency by minimizing energy loss through rotational movement transmission, reducing the overall size, and maintaining a compact design while preventing the pull-in phenomenon.
Implementation Method 1
capacitive detection means 15 disposed in the second zone 12. These capacitive detection means 15 make it possible to measure the displacement of the piston 13, and therefore the difference in pressure between its two faces. They preferably comprise a movable electrode 151 and at least one fixed electrode disposed opposite the movable electrode 151. The electrodes form the plates of a capacitor whose capacitance varies as a function of the displacement of the piston 13.
Implementation Method 2
This pull-in phenomenon is caused by the electrostatic force, which tends to bring the movable electrode closer to the fixed electrode (or to one of the fixed electrodes) and which depends on the square of the polarisation voltage.
Data Source
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AI summary
The invention relates to an electromechanical system (2) comprising: - a frame (10); - a first element (13a) movable relative to the frame (10); - capacitive measurement or actuation means (15') comprising: - a first electrode (151) movable relative to the frame (10); and - at least one electrode fixed relative to the frame (10) and separated from the first movable electrode (151) by a first dielectric medium; - a first movement transmission device (14a) connecting the first movable element (13a) to the first movable electrode (151), the first transmission device (14a) being rotatably movable relative to the frame (10) by means of a plurality of first pivot hinges (16a); - a second element (13b) movable relative to the frame (10), the second movable element (13b) being connected to the capacitive measurement or actuation means (15'), the first movable element (13a) being disposed between the capacitive measurement or actuation means (15') and the second movable element (13b).