Stereo Earphone Cartilage Conduction Vibration Source

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Solution Overview

Problem

Current stereo earphones do not effectively utilize cartilage conduction for clear audio transmission in noisy environments, and existing solutions often require manual adjustment or protrude from the earphone design.

Innovation Solution

A stereo earphone design featuring a cartilage conduction unit with an elastic body that contacts the tragus, incorporating a piezoelectric bimorph element as a vibration source, and an opening and closing mechanism for the passage hole, allowing for symmetrical fitting on both auricles with differential audio signal input.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a bone conduction speaker is employed to provide clear listening in noisy environments, then audio transmission clarity is improved, but the device structure becomes more complex and requires additional components

Engineering Contradiction:
Improveaudio transmission clarityVSAvoiddevice structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the cartilage conduction unit and air conduction earphone into a single integrated stereo earphone device. The cartilage conduction unit includes a vibration source that contacts the tragus, while the air conduction unit includes a speaker that faces the external auditory meatus, allowing both conduction methods to work simultaneously within one device structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The stereo earphone is designed to provide both cartilage conduction and air conduction functions within a single device. The cartilage conduction unit transmits sound vibrations through the tragus bone, while the air conduction unit transmits sound through the external auditory meatus, enabling the device to adapt to different listening environments and user needs.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If manual operation is used to adjust contact pressure between the tragus and vibrating surface, then audio transmission ratio can be altered according to outside noise, but ease of operation deteriorates due to requiring manual adjustment

Engineering Contradiction:
Improveaudio transmission ratio adjustmentVSAvoidmanual adjustment requirement
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The opening and closing mechanism allows the passage hole to be dynamically adjusted between open and closed states, changing the acoustic environment within the external auditory meatus. When the passage hole is closed, it creates a sealed cavity that enhances sound pressure and improves sound quality in noisy environments without requiring manual pressure adjustment.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the vibration source is positioned to contact the tragus for cartilage conduction, then cartilage conduction effectiveness is improved, but the earphone profile becomes more bulky

Engineering Contradiction:
Improvecartilage conduction effectivenessVSAvoidearphone profile
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The cartilage conduction unit is nested within the overall earphone structure, with the vibration source positioned to contact the tragus while being supported by the thick portion of the cartilage conduction unit. The opening and closing mechanism is integrated into the earphone body, allowing the passage hole to be opened or closed without adding significant external bulk to the device.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Object-affected harmful factors

If an opening and closing mechanism is added to control the passage hole, then noise interference is reduced, but device complexity increases

Engineering Contradiction:
Improvenoise interferenceVSAvoidmechanism complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The opening and closing mechanism extracts the function of noise control by isolating the passage hole from the external environment. When the passage hole is closed, it prevents outside noise from entering the external auditory meatus, thereby reducing noise interference without requiring complex active noise cancellation systems.

Inventive Principle:
Principle #2Taking out (Extraction)

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 design provides clear and balanced audio transmission using cartilage conduction, reducing noise interference and maintaining a sleek earphone profile by integrating the vibration source within the earphone's structure.

Implementation Method 1

incorporating a piezoelectric bimorph element as a vibration source

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a cartilage conduction unit that closely bonds to the rear outer side of the base of the auricle

Methodology Applied
Scientific EffectCartilage conduction: Vibration

Data Source

PatentEP2869591B1Stereo earphone
Publication Date: 2020.12.09 FINEWELL
  • EP2869591B1 patent drawingFigure 1
  • EP2869591B1 patent drawingFigure 2A~2B
  • EP2869591B1 patent drawingFigure 3

AI summary

There is provided is a stereo headphone provided with a pair of earphones having a cartilage conduction unit, a sheath unit connected to the cartilage conduction unit, and a piezoelectric bimorph of a vibration source connected to the cartilage conduction unit covered by the sheath unit without making contact with the inner wall thereof. The cartilage conduction unit is an elastic body. The cartilage conduction unit is in contact with the entrance to the external auditory meatus and has a passage hole in communication with the external auditory meatus. The vibration source is supported by a thick portion on the tragus side at the periphery of the passage hole. In accordance with a more specific feature, the thick portion is provided. The outer shape of the sheath has a thickness in the direction of the earhole that is less than the thickness in the direction orthogonal thereto. A guide part for directing the sheath to the intertragic notch is provided. There is provided a stereo earphone provided with a pair of earphones having a cartilage conduction unit and an adhesive sheet provided to a contact part between the cartilage conduction unit and the ear cartilage. The adhesive sheet is provided to the portion where the cartilage conduction unit is in contact with the cavum conchae or the portion where the cartilage conduction is in contact with the outer side of the of the auricle.