Thin Filtering Membrane for Acoustic Transducer Contamination Protection
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Solution Overview
Problem
Existing MEMS acoustic transducers face challenges in compact design due to the thickness of conventional filters, which affects acoustic performance and signal-to-noise ratio, especially in portable applications where contamination protection is needed without increasing device dimensions.
Innovation Solution
A filtering membrane with a limited thickness, comprising a supporting layer and a filtering layer with specific dimensions and material compatibility, is integrated between the acoustic chamber and the sound port, minimizing the impact on acoustic performance while preventing contaminant particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional filter is used to protect the acoustic chamber from contamination, then the protection effectiveness is improved, but the filter thickness increases which degrades acoustic performance and signal-to-noise ratio
Solution Approach 1:
The patent applies this principle by using a thin film filtering membrane with thickness between 1-10 micrometers instead of conventional thick filters. The membrane comprises a supporting layer and a filtering layer that can be deposited directly onto the sound port, providing effective contamination protection while maintaining acoustic performance due to its minimal thickness.
Solution Approach 2:
The patent applies this principle by using a porous filtering layer with controlled porosity to allow acoustic waves to pass through while blocking contaminant particles. The porous structure enables the membrane to function as an effective filter with minimal thickness, resolving the contradiction between protection effectiveness and acoustic performance.
2Loss of information
If the filter thickness is reduced to maintain acoustic performance, then the signal-to-noise ratio is improved, but the contamination protection capability is worsened
Solution Approach 1:
The patent applies this principle by creating a composite filtering membrane consisting of a supporting layer and a filtering layer with different functional properties. The supporting layer provides mechanical strength while the filtering layer with specific porosity provides contamination protection, enabling thin film design that maintains both acoustic performance and protection capability.
Solution Approach 2:
The patent uses thin film technology to achieve effective contamination protection with minimal thickness (1-10 micrometers), ensuring that the membrane does not significantly degrade acoustic performance or signal-to-noise ratio while still providing adequate filtration.
3Volume of moving object
If a thin filtering membrane is used to maintain compact design, then the device dimensions are reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent applies this principle by integrating the filtering membrane directly onto the sound port structure, combining the filter with the existing acoustic transducer components. This integration approach reduces overall device dimensions and eliminates the need for separate filter assembly steps, thereby reducing manufacturing complexity despite the advanced membrane structure.
Solution Approach 2:
The patent uses parameter changes in the membrane deposition process, controlling thickness (1-10 micrometers) and porosity to achieve the desired balance between compactness and manufacturability. By optimizing these parameters, the patent enables thin film integration that maintains compact device dimensions while using established deposition techniques.
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 provides effective contamination protection with negligible impact on the signal-to-noise ratio and allows for a more compact design, enhancing the flexibility of the acoustic transducer device without degrading acoustic performance.
Implementation Method 1
a filtering layer (56), arranged on the supporting layer (54), comprising a plurality of through openings (58)
Implementation Method 2
In the case where a capacitive sensing principle is used, the microelectromechanical sensitive structure in general comprises a mobile electrode, obtained as a diaphragm or membrane, arranged facing a fixed electrode, to provide the plates of a sensing capacitor with variable capacitance
Data Source
AI summary
A method for manufacturing a filtering module comprising the steps of: forming a multilayer body comprising a filter layer of semiconductor material and having a thickness of less than 10 μm, a first structural layer coupled to a first side of the filter layer, and a second structural layer coupled to a second side, opposite to the first side, of the filter layer; forming a recess in the first structural layer, which extends throughout its thickness; removing selective portions, exposed through the recess, of the filter layer to form a plurality of openings, which extend throughout the thickness of the filter layer; and completely removing the second structural layer to connect fluidically the first and second sides of the filter layer, thus forming a filtering membrane designed to inhibit passage of contaminating particles.