Microphone Lid With Offset Port And Insert
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Solution Overview
Problem
Existing microphones, particularly MEMS capacitors, face challenges in achieving a large back volume for improved sensitivity and signal-to-noise ratio due to mechanical coupling and temperature-dependent behavior, while encapsulations with small back volumes deteriorate the signal-to-noise ratio.
Innovation Solution
A microphone design featuring a transducer element between a substrate and a lid with a non-overlapping opening, an insert connecting the front volume to the lid's opening, and a path that maintains acoustic communication while providing mechanical and acoustic decoupling, allowing for a large back volume and reduced temperature sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the opening of the lid is arranged directly above the transducer element to simplify the structure, then the manufacturing process is easier, but dust can easily enter and deposit on the membrane, deteriorating microphone sensitivity
Solution Approach 1:
The patent resolves the contradiction by changing the spatial arrangement from a vertical alignment (opening directly above transducer) to a lateral offset configuration. The opening is positioned at the edge of the lid, laterally displaced from the transducer element, creating a spatial separation that prevents dust deposition while maintaining structural simplicity through the insert component.
2Strength
If the lid is strongly mechanically coupled to the microphone chip to ensure structural stability, then the mechanical strength is improved, but temperature-dependent behavior is introduced that influences transducer functionality
Solution Approach 1:
The insert serves as an intermediary component between the lid and the microphone chip. It provides the necessary mechanical coupling to hold the lid in place while introducing compliance that absorbs thermal expansion differences, thereby preventing the transmission of temperature-induced stresses to the transducer element and maintaining functional stability across temperature variations.
3Reliability
If the back volume is made large to improve sensitivity and signal-to-noise ratio, then the acoustic performance is improved, but the mechanical coupling and temperature sensitivity problems persist
Solution Approach 1:
The patent segments the enclosure into distinct functional zones: a large back volume for optimal acoustic performance and sensitivity, and a separate front volume containing the transducer element. The insert creates an acoustic seal between these zones while maintaining mechanical support, allowing the back volume to be maximized without compromising the transducer's thermal stability.
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 design enhances microphone durability by minimizing dust deposition on the membrane, offers flexibility in sound port placement, maintains signal quality, and reduces temperature sensitivity, enabling operation across a broader temperature range with improved signal-to-noise ratio.
Implementation Method 1
the microphone may be a capacitor microphone
Data Source
AI summary
A microphone and a method for manufacturing a microphone are disclosed. In an embodiment the microphone includes a substrate, a transducer element defining a front volume and a lid arranged such that the transducer element is arranged between the substrate and the lid, wherein the lid comprises an opening which is arranged non-overlapping to the front volume of the transducer element. The microphone further includes an insert arranged between the lid and the transducer element, wherein the insert includes a path which connects the front volume of the transducer element to the opening of the lid.