Electret Microphone Cap Member Segmentation for Suction Stability

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Solution Overview

Problem

Conventional electret condenser microphones face challenges during reflow mounting, including difficulty in maintaining posture during suction transportation and adverse effects from heat transmission through acoustic holes, which can damage the diaphragm and electret layer.

Innovation Solution

A conductive capsule with a cap member featuring acoustic holes along its circumference, positioned between the capacitor section and the top member, reduces heat transmission and stabilizes the microphone's posture during transportation, using arc slits to minimize air and debris entry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a suction-type transporting device is used to transport the ECM, then the mounting speed is improved, but the ECM posture becomes unstable and the device may fall off

Engineering Contradiction:
Improvemounting speedVSAvoidECM posture stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The top surface of the capsule is divided into two distinct regions: a first region with an acoustic hole for sound transmission and a second region without an acoustic hole for suction transportation. This segmentation allows the suction device to contact the second region and transport the ECM while maintaining stable posture, preventing the device from inclining or falling off during the mounting process.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If the drawing force of the transporting device is increased to improve posture stability, then the posture stability is improved, but the top surface of the capsule becomes deformed

Engineering Contradiction:
ImproveECM posture stabilityVSAvoidcapsule top surface shape
Core Design Contradiction:
Stability of the object's compositionVSShape

Solution Approach 1:

By segmenting the top surface into a first region with an acoustic hole and a second region without an acoustic hole, the invention provides a dedicated suction area that can be contacted by the transporting device. This allows sufficient drawing force to be applied to the second region for stable transportation without deforming the acoustic hole structure in the first region, thus maintaining both posture stability and structural integrity.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If the acoustic hole is provided in the top surface for sound transmission, then the acoustic function is improved, but heat and air enter the capsule causing damage to internal components

Engineering Contradiction:
Improveacoustic functionVSAvoidheat and air intrusion
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The top surface is segmented into a first region with an acoustic hole for sound transmission and a second region without an acoustic hole. The cap member is positioned between the capacitor section and the top member, creating a barrier that blocks heat and air from entering the capsule through the acoustic hole during the reflow mounting process, while still allowing sound waves to pass through the acoustic hole for normal acoustic function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cap member acts as an intermediary barrier between the external environment (heated air and heat sources during reflow mounting) and the internal components (diaphragm and electret layer). It blocks harmful heat and air from reaching the sensitive internal components while allowing sound transmission through the acoustic hole, thus protecting the components without compromising acoustic function.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of operation

If the acoustic hole is positioned centrally for optimal sound transmission, then the acoustic performance is improved, but the suction device cannot transport the ECM without causing inclination

Engineering Contradiction:
Improveacoustic performanceVSAvoidtransportation posture stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The top surface is segmented into a first region with a centrally positioned acoustic hole for optimal acoustic performance and a second region without an acoustic hole for suction transportation. This segmentation allows the acoustic hole to remain in the optimal central position for sound transmission while providing a separate second region for the suction device to contact and transport the ECM stably without causing inclination or falling off.

Inventive Principle:
Principle #1Segmentation

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 effectively prevents diaphragm slackening and electret layer polarization, ensures reliable suction transportation, and enhances the microphone's durability by reducing heat impact and protecting internal components from air and debris.

Implementation Method 1

a capacitor section including a diaphragm, a back electrode plate arranged to face either surface of the diaphragm, and a electret layer provided on the diaphragm or the back electrode plate

Methodology Applied
Scientific EffectElectret: Electret

Implementation Method 2

the reflow mounting process sometimes uses a suction-type transporting device to transport the ECM to the wiring substrate

Methodology Applied
Scientific EffectSuction: Suction

Data Source

PatentEP2224750B1Electret condenser microphone
Publication Date: 2012.03.28 HOSIDEN CORP
  • EP2224750B1 patent drawingFigure 1
  • EP2224750B1 patent drawingFigure 2~3
  • EP2224750B1 patent drawingFigure 4~6

AI summary

An electret condenser microphone comprises a conductive capsule including an opening formed in a top member, a capacitor section including a diaphragm, a back electrode plate arranged to face either surface of the diaphragm, and a electret layer provided on the diaphragm or the back electrode plate, which are housed in the capsule, and a cap member provided between the capacitor section and the top member of the capsule and including an acoustic hole formed in a portion exposed to the outside through the opening, wherein the cap member further includes a suctioned portion formed in a central portion thereof to be drawn by a suction-type transporting device, the acoustic holes being arranged along the circumference of the suctioned portion.