MEMS Diaphragm Over Electrode Gap for Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional microelectromechanical systems (MEMS) with comb electrode structures face limitations in reducing ventilation areas, which affects low-frequency sound resolution due to large gaps between electrode fingers, and silicon MEMS with perforated back plates suffer from noise issues due to air friction.
Innovation Solution
A microelectromechanical device with a diaphragm and a comb electrode structure where the diaphragm is arranged over a gap between the electrodes, allowing independent ventilation and reducing fluidic damping, thereby improving low-frequency resolution and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the distance between electrode fingers is reduced to minimize ventilation areas, then noise due to air friction is reduced, but manufacturing precision becomes more difficult to achieve
Solution Approach 1:
The patent transitions from planar electrode arrangements to a three-dimensional configuration where the diaphragm is positioned over the gap between electrode fingers. This vertical positioning allows ventilation areas to be minimized without requiring extremely small lateral distances between electrodes, thus avoiding manufacturing precision limitations while still reducing air friction noise.
Solution Approach 2:
The patent changes the geometric parameters of the electrode structure by introducing a vertical dimension for the diaphragm positioning. Instead of only reducing the lateral gap between fingers (which hits manufacturing limits), the solution adjusts the vertical position and dimensions of the diaphragm to control ventilation areas, enabling noise reduction through parameter optimization within feasible manufacturing ranges.
2Ease of manufacture
If large gaps between electrode fingers are used, then manufacturing is easier, but low-frequency sound resolution deteriorates due to increased ventilation areas
Solution Approach 1:
By positioning the diaphragm vertically over the gap between electrode fingers rather than relying solely on lateral spacing, the patent achieves effective ventilation area control with manufacturable gap dimensions. This three-dimensional arrangement allows larger lateral gaps (easier to manufacture) while maintaining small effective ventilation areas through the diaphragm's vertical positioning.
Solution Approach 2:
The patent optimizes the vertical position and dimensions of the diaphragm as key parameters to control ventilation areas. This allows the use of larger, more manufacturable lateral gaps between electrode fingers while maintaining low-frequency sound resolution through appropriate diaphragm positioning and sizing that limits the effective ventilation cross-section.
3Ease of operation
If a perforated back plate is used for ventilation, then acoustic access is improved, but noise increases due to air friction in the perforations
Solution Approach 1:
The patent extracts the ventilation function from the back plate and relocates it to the gap region between electrode fingers, where the diaphragm is positioned over this gap. This separation allows the back plate to provide acoustic access without creating noise-generating perforations, as the ventilation occurs through the electrode gap rather than through the back plate material.
Solution Approach 2:
The diaphragm acts as an intermediary element positioned over the electrode gap, mediating between the acoustic environment and the electrode structure. It allows acoustic access through the gap region while preventing direct air friction noise that would occur with perforated back plates, effectively decoupling the ventilation function from the noise-generating perforation structure.
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 low-frequency sound resolution and reduces noise by optimizing the electrode arrangement and ventilation in the microelectromechanical device, addressing the limitations of existing MEMS technologies.
Implementation Method 1
a comb electrode structure, which includes: a dynamic electrode (110) mounted to the means for actuating; a stator electrode (120) mounted to the substrate, wherein the dynamic electrode is laterally adjacent to the stator electrode
Data Source
AI summary
A microelectromechanical device, a microelectromechanical system, and a method of manufacturing a microelectromechanical device, wherein the microelectromechanical device may include: a substrate; a diaphragm mounted to the substrate; a first electrode mounted to the diaphragm; a second electrode mounted to the substrate; wherein the first electrode is laterally adjacent to the second electrode; and wherein the diaphragm is arranged over a gap between the first electrode and the second electrode.