Open-Ear Acoustic Transducer Layout for Low Sound Spillage

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Open audio devices produce more sound spillage due to their acoustic transducers being spaced from the ear, detracting from their usefulness and desirability.

Innovation Solution

The electro-acoustic transducer is designed with two spaced sound-emitting openings, one closer to the ear and one farther away, emitting sound out of phase to achieve dipole-like behavior, minimizing sound spillage while maintaining a thin profile.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the acoustic transducer is spaced from the ear in open audio devices, then the user can be more aware of the environment, but sound spillage increases and can be heard by others

Engineering Contradiction:
Improveenvironmental awarenessVSAvoidsound spillage
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The transducer is divided into two separate sound-emitting openings: a first opening closer to the ear and a second opening farther from the ear. This segmentation allows independent control of sound emission paths, enabling the closer opening to deliver sound to the ear while the farther opening redirects sound away from the environment, thus reducing spillage while maintaining environmental awareness

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The two sound-emitting openings are positioned asymmetrically at different distances from the ear. This asymmetric configuration creates different acoustic paths: sound from the closer opening reaches the ear directly, while sound from the farther opening is directed away from the ear and into the environment in a controlled manner, reducing unwanted spillage to others

Inventive Principle:
Principle #4Asymmetry

2Object-generated harmful factors

If the transducer is designed to reduce sound spillage, then environmental sound leakage decreases, but the device complexity increases

Engineering Contradiction:
Improvesound spillageVSAvoidtransducer structure
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The transducer employs a thin diaphragm that can emit sound from both its front and rear surfaces. This thin-film structure allows the creation of two sound-emitting openings without significantly increasing the transducer's thickness or structural complexity, while effectively controlling sound spillage through the dual-opening configuration

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention changes the spatial parameters of sound emission by positioning two openings at different distances from the ear. This parameter change (distance variation) creates different acoustic radiation patterns that reduce spillage without requiring complex additional components, maintaining relatively simple transducer structure

Inventive Principle:
Principle #35Parameter changes

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 transducer effectively delivers high sound pressure to the ear while minimizing sound spillage to the environment, enhancing the usability and desirability of open audio devices.

Implementation Method 1

The transducer diaphragm is flat or nearly flat. The transducer has two spaced sound-emitting openings. One opening receives sound from the front face of the transducer diaphragm. The other opening receives sound from the rear face of the diaphragm. Because the sound is emitted from both faces of the diaphragm, the sound is inherently out of phase. The sound from the openings will thus tend to cancel in the far field, resulting in dipole-like behavior.

Methodology Applied
Scientific EffectAcoustic radiation and interference: Sound

Data Source

PatentEP3967056B1Acoustic device
Publication Date: 2026.01.07 BOSE CORP
  • EP3967056B1 patent drawingFigure 1~2A
  • EP3967056B1 patent drawingFigure 2B~3
  • EP3967056B1 patent drawingFigure 4~5

AI summary

An acoustic device with an open audio device structure that is configured to be carried on the head or upper torso of a user, and an electro-acoustic transducer carried by the open audio device structure and comprising a flat rectangular diaphragm comprising a front face and a rear face, the diaphragm configured to radiate front acoustic radiation from its front face and into a front acoustic volume that has a first sound-emitting outlet proximate a first corner of the transducer and further configured to radiate rear acoustic radiation from its rear face and into a rear acoustic volume that has a second sound-emitting outlet proximate a second corner of the transducer that is diagonally opposite the first corner.