Sound Pick-up Device with Shielded Reference Microphone

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Solution Overview

Problem

Conventional sound processing devices face challenges in effectively reducing internal noise during sound signal collection, particularly in sealed electronic devices like digital cameras, where noise generated by image stabilization mechanisms and other internal sources interferes with external sound pickup.

Innovation Solution

The implementation of a sound pick-up device with a housing containing a main microphone, a reference microphone, and shielding structures (first, second, and third shields) that isolate the reference microphone from external noise, allowing it to capture internal noise sources for noise suppression, which is then subtracted from the main sound signal using an adaptive filter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the reference microphone is placed inside the housing to capture internal noise, then noise suppression capability is improved, but external sound interference with the reference microphone increases

Engineering Contradiction:

Improvenoise suppression capabilityVSAvoidexternal sound interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The housing internal space is segmented into multiple regions using shields. The reference microphone is placed in a dedicated region isolated from external sound paths, while the main microphone occupies another region. This spatial segmentation allows the reference microphone to capture internal noise without being contaminated by external sounds entering through the sound hole.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Sound blocking shields act as intermediary structures between the external environment and the reference microphone. These shields strategically block sound paths from the sound hole to the reference microphone's location, while still allowing the reference microphone to detect internal noise generated within the housing.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If the reference microphone is positioned away from the main microphone to avoid interference, then measurement accuracy is improved, but the ability to capture correlated internal noise decreases

Engineering Contradiction:

Improvesignal separation accuracyVSAvoidnoise correlation accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

Different regions within the housing are assigned different functional qualities. The reference microphone is positioned in a region with high internal noise exposure but low external sound exposure, while the main microphone is positioned in a region optimized for external sound capture. This local differentiation of acoustic environments allows both microphones to perform their specific functions effectively.

Inventive Principle:

Principle #3Local quality

3Measurement precision

If sound blocking shields are added to isolate the reference microphone, then noise suppression is improved, but device complexity increases

Engineering Contradiction:

Improvenoise reduction effectivenessVSAvoidshielding structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The sound blocking shields are integrated with existing housing structures and component arrangements. Rather than adding completely separate shielding components, the design merges the shielding function with the housing's internal framework and existing structural elements, reducing the overall complexity increase while maintaining effective noise isolation.

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 configuration significantly reduces noise in the sound signal collected by the main microphone, enhancing the quality of sound recordings in electronic devices prone to internal noise, such as digital cameras with image stabilization mechanisms.

Implementation Method 1

a first shield blocks between the inside of the housing and the inside of the main microphone

Methodology Applied

Scientific EffectSound blocking: Acoustic Absorption

Implementation Method 2

a second shield blocks between the outside of the housing and the inside of the reference microphone

Methodology Applied

Scientific EffectSound blocking: Acoustic Absorption

Implementation Method 3

a third shield blocks between the inside of the housing and the inside of the reference microphone

Methodology Applied

Scientific EffectSound blocking: Acoustic Absorption

Data Source

PatentUS10555062B2Sound pick up device with sound blocking shields and imaging device including the same

Publication Date: 2020.02.04 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

Provided is a sound pick-up device which includes: a housing having a sound hole; a main microphone which is disposed in the inside of the housing, receives sound pressure from the outside of the housing through the sound hole, and generates a first sound signal; a reference microphone which is disposed in the inside of the housing and in a proximity of the main microphone and generates a second sound signal; a first shield which blocks between the inside of the housing and the inside of the main microphone; a second shield which blocks between the outside of the housing and the inside of the reference microphone; and a third shield which blocks between the inside of the housing and the inside of the reference microphone.