Earphone Ear Canal Protrusion Design for Acoustic Coupling

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Solution Overview

Problem

Existing earphone devices often compromise on acoustic coupling, comfort, and secure attachment due to issues like high-frequency filtering, occlusion, and discomfort caused by narrow sound bores and improper ear canal engagement.

Innovation Solution

The earphone device features a cross-sectionally smaller ear canal protrusion with a convex outer side and concave inner side, allowing it to be supported by the ear canal while maintaining a large sound opening, and includes a conchal wall stabilizer for secure fixation, minimizing high-frequency damping and discomfort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a narrow sound bore is provided in the ear canal protrusion to lead sound directly into the ear canal, then the sound is directed efficiently, but the higher frequencies are dampened acting as a high frequency filter

Engineering Contradiction:
Improveacoustic couplingVSAvoidhigh frequency filtering
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The ear canal protrusion is divided into two functional zones: a first side that engages with the ear canal wall for support and positioning, and a second side that borders the sound opening to direct sound. This segmentation allows the protrusion to fulfill both mechanical support and acoustic guidance functions without requiring a narrow sound bore, thereby preserving high frequency content while maintaining reliable acoustic coupling.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the ear canal protrusion is made to engage the ear canal wall for support, then the device is securely held, but occlusion effects and discomfort occur due to sealing off the ear canal

Engineering Contradiction:
Improvesecure attachmentVSAvoidocclusion effects
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The ear canal protrusion is designed with asymmetric local qualities: the first side has engagement features for securing the device to the ear canal wall, while the second side maintains an open configuration that borders the sound opening. This local differentiation allows secure attachment through the first side's engagement with the ear canal wall while preventing occlusion effects by leaving the second side open, thus avoiding discomfort from ear canal sealing.

Inventive Principle:
Principle #3Local quality

3Volume of moving object

If a small speaker is fitted into the tip of the ear canal protrusion, then the device can be compact, but the sound opening becomes restricted

Engineering Contradiction:
Improvedevice sizeVSAvoidsound opening area
Core Design Contradiction:
Volume of moving objectVSArea of stationary object

Solution Approach 1:

Instead of placing the speaker at the tip of the ear canal protrusion (one-dimensional constraint), the sound opening is positioned laterally beside the protrusion. The second side of the protrusion borders this lateral sound opening, creating a two-dimensional spatial arrangement. This dimensional change allows a larger sound opening area while maintaining a compact overall device volume, as the sound path extends laterally rather than requiring a deep protrusion tip.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP2177050B1Earphone device with ear canal protrusion
Publication Date: 2018.01.03 GN AUDIO AS
  • EP2177050B1 patent drawingFigure 1~2
  • EP2177050B1 patent drawingFigure 3~6
  • EP2177050B1 patent drawingFigure 7~9

AI summary

An earphone device (1) comprising a main body (14) to be inserted in to the outer ear (28) of a user. The main body (14) has a first side (5) that faces the user's head when inserted, a cavity (13) and a sound opening (2) connecting the first side (5) with the cavity (13). The main body (14) further comprises an ear canal protrusion (3) to be inserted into the ear canal (7). The cross section of the ear canal protrusion (3) is smaller than the cross section of the ear canal (7) and the ear canal protrusion (3) is having a first side (8) adapted to lie against the ear canal wall (10) and a second side (9) lying opposite the first side (8) and beside the sound opening (2).