Artificial Ear Model for Vibration Transmission Measurement
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Solution Overview
Problem
There is a need for a measurement device and method that can accurately evaluate the vibration transmission characteristics of acoustic devices like earphones and headphones, which transmit sound via vibration to the human ear, to assess their effectiveness in stimulating the auditory nerve.
Innovation Solution
A measurement device comprising an ear model unit with an artificial external ear canal and a microphone to measure air-conducted sound, along with vibration detection elements to quantify the vibration levels transmitted to the ear, allowing for the evaluation of acoustic devices that include a vibrating body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If vibration transmission measurement is performed using a simple artificial ear model, then the measurement setup is simple and easy to operate, but the measurement precision of vibration transmission characteristics is insufficient
Solution Approach 1:
The patent creates a simplified artificial ear model that copies the essential vibration transmission characteristics of the human ear without replicating its full complexity. The artificial ear includes a head model, ear canal, eardrum, and middle ear structures that reproduce the key vibration transmission paths from the outer ear to the inner ear, enabling accurate measurement while maintaining operational simplicity.
Solution Approach 2:
The artificial ear model serves as an intermediary between the acoustic device under test and the measurement sensors. It translates the complex vibration transmission characteristics of the human ear into measurable physical quantities (such as eardrum vibration and ossicle movement) that can be accurately detected by sensors, thereby bridging the gap between simple measurement setup and precise vibration characterization.
2Measurement precision
If complex measurement systems are used to accurately measure vibration transmission, then measurement precision is improved, but the device complexity increases
Solution Approach 1:
Instead of using complex measurement systems to directly measure vibrations in the human ear, the patent creates a simplified artificial copy of the ear's vibration transmission system. This artificial model reproduces the essential vibration paths and characteristics, allowing accurate measurement using simpler sensors and measurement equipment while avoiding the need for invasive or highly complex measurement apparatus.
Solution Approach 2:
The artificial ear model is segmented into distinct functional components (head model, ear canal, eardrum, ossicles, inner ear structures) that can be independently constructed and measured. This segmentation allows each component to be optimized for its specific function while keeping the overall measurement system manageable and not excessively complex.
3Measurement precision
If the artificial ear model includes detailed anatomical structures, then the measurement precision of vibration transmission is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The artificial ear model copies only the essential vibration transmission structures of the human ear rather than replicating every anatomical detail. It includes the critical components (ear canal, eardrum, ossicles, inner ear) that dominate vibration transmission, while simplifying or omitting less critical anatomical features, thereby reducing manufacturing precision requirements while maintaining measurement accuracy.
Solution Approach 2:
The artificial ear model applies different levels of structural detail and material fidelity to different regions based on their importance for vibration transmission. Critical regions such as the eardrum and ossicle connections are constructed with high precision and appropriate material properties, while less critical regions are simplified, optimizing the balance between measurement accuracy and manufacturing feasibility.
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
Enables accurate measurement and evaluation of the vibration transmission characteristics to the human ear, providing detailed insights into the performance of earphones, headphones, and similar devices by correlating vibration levels with auditory sensations.
Implementation Method 1
when voltage is applied to the piezoelectric bimorph in the vibrating body, the piezoelectric material expands and contracts in the longitudinal direction, causing the vibrating body to undergo bending vibration
Implementation Method 2
a microphone configured to measure air-conducted sound generated in an artificial external ear canal unit continuous with the ear model
Data Source
AI summary
A measurement device and measurement method for evaluating an acoustic device that allows a sound to be transmitted via vibration transmission by being held by a human ear includes an ear model unit having an ear model modeled after a human ear and an artificial external ear canal unit continuous with the ear model. The ear model unit is formed from rubber, a same material as an auricle model conforming to IEC 60318-7 or IEC 60268-7, or a material having a Shore hardness of from 30 to 60. The ear model is provided with an auricle or a hole which holds the acoustic device. A microphone is configured to measure an air-conducted component generated within an artificial ear canal of the artificial ear canal unit by vibration transmitted to the ear model unit from the acoustic device held by the auricle or the hole.