Miniature Receiver Diaphragm Acoustic Coupling

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Solution Overview

Problem

Conventional miniature receivers with multiple diaphragms face challenges in achieving high sound pressure levels due to the need for high stiffness membranes or motors, which can reduce efficiency and limit the effective diaphragm area.

Innovation Solution

A miniature receiver design featuring first and second moveable diaphragms acoustically connected via an intermediate volume with lower acoustic compliance than the diaphragms, ensuring they are driven in the same direction and perform similar volume displacements, allowing for a larger effective diaphragm area and improved sound pressure levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If multiple diaphragms are placed in parallel with larger area to increase sound pressure level, then the sound pressure level is improved, but the acoustic compliance becomes too large requiring high stiffness membranes or motors which reduces driving efficiency

Engineering Contradiction:

Improvesound pressure levelVSAvoiddriving efficiency

Core Design Contradiction:

Stress or pressureVSUse of energy by moving object

Solution Approach 1:

The receiver is segmented into multiple diaphragms (first and second diaphragms) that are acoustically coupled in series through an intermediate volume, rather than placing them in parallel. This segmentation allows each diaphragm to contribute to the overall sound pressure while maintaining appropriate compliance through the series acoustic coupling, thus improving sound pressure level without requiring high stiffness membranes or motors that would reduce driving efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An intermediate volume with specific acoustic compliance is introduced as a mediator between the first and second diaphragms. This intermediate volume acts as an acoustic coupling element that enables the diaphragms to be acoustically connected in series, allowing them to move in the same direction while maintaining optimal compliance. The intermediary volume thus resolves the contradiction by enabling multiple diaphragms to work together efficiently without requiring excessive stiffness.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stress or pressure

If larger diaphragm area is used to increase sound pressure level, then the sound pressure level is improved, but the receiver size increases which conflicts with miniature receiver requirements

Engineering Contradiction:

Improvesound pressure levelVSAvoidreceiver size

Core Design Contradiction:

Stress or pressureVSVolume of moving object

Solution Approach 1:

The patent transitions from a single-plane diaphragm configuration to a three-dimensional stacked configuration with multiple diaphragms separated by an intermediate volume. This dimensional change allows the effective radiating area to be increased by utilizing vertical space rather than expanding the horizontal footprint, thus improving sound pressure level while maintaining a compact receiver size suitable for hearing aids and hearables.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The receiver employs a nested structure where the first and second diaphragms are stacked one above the other, with the intermediate volume nested between them. This nesting arrangement allows multiple diaphragms to be contained within a compact vertical space, effectively increasing the total radiating area without proportionally increasing the overall receiver volume, thereby resolving the contradiction between sound pressure level and receiver size.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 sound pressure levels by enabling more compliant diaphragm designs and increasing active diaphragm area, optimizing the ratio of receiver stiffness to rear volume stiffness, thus improving efficiency and sound output.

Implementation Method 1

each comprises a substantially plane diaphragm comprising an integrated drive structure comprising a piezoelectric material layer (207) arranged between a first and a second electrode (206, 208)

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the acoustic compliance of the intermediate volume (103) is smaller than the acoustic compliances of the respective first and second moveable diaphragms (105, 106), where the smaller acoustic compliance of the intermediate volume (103) relative to the acoustic compliances of the first and second moveable diaphragms (105, 106) ensures that the first and second moveable diaphragms (105, 106) are driven in the same direction and perform the same volume displacements

Methodology Applied

Scientific EffectAcoustic compliance: Acoustics

Data Source

PatentEP3579578B1Miniature receiver

Publication Date: 2022.02.23 SONION NEDERLAND BV

Figure 1
Figure 2a~2c
Figure 3a)~3c)

AI summary

The present invention relates to a miniature receiver comprising a first moveable diaphragm being acoustically connected to an intermediate volume, and a second moveable diaphragm being acoustically connected to the intermediate volume and a rear volume, wherein the acoustic compliance of the intermediate volume is smaller than the acoustic compliances of the respective first and second moveable diaphragms. The present invention further relates to an associated method.