Microphone Substrate Cavity Layout for Rear Chamber Volume
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Solution Overview
Problem
Existing pressure sensor and microphone systems face challenges in maximizing rear chamber volume while minimizing overall bulk, leading to reduced performance due to the placement of ASICs and electromechanical components, which affects signal-to-noise ratio and low-frequency response.
Innovation Solution
The system incorporates a substrate with a cavity and hole arrangement that allows for a larger rear chamber volume by positioning the electromechanical transducer and signal processing means in separate cavities, with a shoulder formed by the cavity and hole, enabling robust assembly and compactness gains, and using conducting elements to connect these components efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the ASIC is disposed in a cavity located on the side of the upper face of the assembling substrate, then the bulk of the system is reduced, but the rear chamber volume is reduced which deteriorates performance
Solution Approach 1:
The patent divides the housing into separate cavities: a first cavity for the electromechanical component and a second cavity for the ASIC. This segmentation allows each component to be positioned in optimal locations without compromising the rear chamber volume, as the ASIC cavity is distinct from the rear chamber space.
Solution Approach 2:
The patent transitions from a single-layer stacked arrangement to a three-dimensional distributed arrangement where the ASIC is positioned in a separate cavity on the upper face while the electromechanical component occupies a cavity on the lower face. This spatial redistribution in multiple dimensions enables both compactness and adequate rear chamber volume.
2Adaptability or versatility
If the electromechanical component is placed in a cavity on the upper face with the ASIC stacked on it, then the input port configuration is changed, but the front chamber volume increases causing spurious resonance and the rear chamber volume is reduced
Solution Approach 1:
The patent segments the housing into a first cavity for the electromechanical component and a second cavity for the ASIC, allowing the input port to be configured in the cap while maintaining adequate rear chamber volume. The segmented structure prevents the front chamber volume from becoming excessive.
Solution Approach 2:
The patent introduces a cap as an intermediary element that serves as the input port while the electromechanical component is housed in a separate cavity. This intermediary configuration allows acoustic waves to enter through the cap without compromising the rear chamber volume or causing spurious resonance.
3Volume of moving object
If the ASIC is placed in the rear chamber to reduce bulk, then the overall size is minimized, but the rear chamber volume is reduced which deteriorates signal-to-noise ratio and low frequency response
Solution Approach 1:
The patent segments the housing into separate cavities for the electromechanical component and the ASIC, allowing the ASIC to be positioned without occupying the rear chamber volume. This segmentation preserves the signal-to-noise ratio and low frequency response while maintaining compact overall size.
Solution Approach 2:
The patent applies local quality by positioning the ASIC in a specific cavity location rather than uniformly distributing it. The ASIC is placed in a cavity on the upper face away from the rear chamber, creating localized optimal positioning that preserves acoustic performance while achieving compactness.
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 rear chamber volume, reduces bulk, and improves the signal-to-noise ratio and low-frequency response of pressure sensors and microphones, while maintaining compactness and robust assembly.
Implementation Method 1
a sensitive element able to move under the effect of a pressure difference between its faces
Implementation Method 2
an initiation of movement caused by an input sound wave translates into an electric signal, for example a signal due to a capacitance change between a fixed electrode and a movable electrode attached to the membrane
Data Source
AI summary
An electromechanical pressure sensor system, in particular microphone type, including an electromechanical transducer, signal processing device, a substrate for receiving at least one support of the electromechanical transducer and/or signal processing device, a protective cover arranged on the upper face of the substrate, the support of the electromechanical transducer and/or signal processing device being housed in at least one cavity located on the lower face of the substrate is disclosed.