Integrated Cover-Substrate Back Volume for Microphone SNR

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Solution Overview

Problem

The miniaturization of silicon microphones is hindered by the need for a large back volume to achieve high signal-to-noise ratio, which contradicts the trend towards smaller electronic device dimensions.

Innovation Solution

A compact electronic device design where the existing cover or casing, which is already needed for other electronic components, is used to form a large back volume for the electroacoustic transducer, eliminating the need for a separate cover and allowing for a high back volume while maintaining small dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate cover is provided for the electroacoustic transducer to form a back volume, then the signal-to-noise ratio is improved, but the device dimensions increase and weight increases

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoiddevice dimensions

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges the cover for the electroacoustic transducer with the cover for other electronic members into a single integrated cover structure. This unified cover simultaneously forms the back volume for the transducer and provides coverage for other electronic components, thereby achieving the required signal-to-noise ratio without increasing overall device dimensions or weight.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The common cover serves multiple functions: it acts as the back volume enclosure for the electroacoustic transducer, provides protection for other electronic members, and maintains the compact form factor. This multi-functional design eliminates the need for separate covers, resolving the contradiction between performance and miniaturization.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If a separate cover is provided for the electroacoustic transducer to form a back volume, then the signal-to-noise ratio is improved, but the device complexity increases

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines what would traditionally be separate cover structures into a single integrated cover. This merging reduces the number of parts and assembly steps, thereby lowering device complexity while still providing the necessary back volume for high signal-to-noise ratio performance.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If the back volume is increased for high signal-to-noise ratio, then the acoustic performance is improved, but the device weight increases

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoiddevice weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The integrated cover design allows the back volume to be formed using the same structural element that provides coverage for other components. This eliminates the need for additional weight-bearing structures, achieving the required acoustic performance without proportionally increasing device weight.

Inventive Principle:

Principle #5Merging (Combining)

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 achieves a high signal-to-noise ratio with a compact and lightweight device, enabling highly miniaturized silicon microphones with excellent performance.

Implementation Method 1

an electroacoustic transducer configured for converting between an electric signal and an acoustic signal

Methodology Applied

Scientific EffectElectromechanical transduction:

Implementation Method 2

the electroacoustic transducer provides an acoustical coupling between the hollow space and an exterior of the cover-substrate arrangement via the through hole

Methodology Applied

Scientific EffectAcoustic coupling: Acoustics

Data Source

PatentUS9521499B2Electronic device with large back volume for electromechanical transducer

Publication Date: 2016.12.13 INFINEON TECHNOLOGIES AG

AI summary

An electronic device comprising a substrate, a cover delimiting at least a part of a main surface of the substrate to thereby form a cover-substrate arrangement enclosing a hollow space and having a through hole, an electroacoustic transducer configured for converting between an electric signal and an acoustic signal and being mounted on the substrate acoustically coupled with the hollow space in such a way that the hollow space constitutes a back volume of the electroacoustic transducer, wherein the electroacoustic transducer provides an acoustical coupling between the hollow space and an exterior of the cover-substrate arrangement via the through hole, an electronic chip mounted within the cover-substrate arrangement and electrically coupled with the electroacoustic transducer for communicating electric signals between the electronic chip and the electroacoustic transducer, and at least one electronic member mounted on the substrate within the cover-substrate arrangement and configured for providing an electronic function.