Metasurface Earplug for High-Frequency Noise Filtering
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Solution Overview
Problem
Existing earplugs either require charging and are expensive due to noise canceling technology, or they are inexpensive but lack effective noise reduction, particularly for high-frequency sounds.
Innovation Solution
A high-frequency noise filtering earplug utilizing a metasurface, which includes an eartip, an interference attenuation module with reflective cavities, and a connecting tube to effectively reduce high-frequency noise through interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If noise canceling technology is used in earplugs, then noise reduction performance is improved, but cost and complexity increase due to charging requirements
Solution Approach 1:
The patent replaces electronic active noise canceling systems with a passive acoustic metasurface structure. The metasurface uses carefully designed cavity resonators and damping materials to achieve noise reduction without requiring power sources, batteries, or electronic components. This mechanical/acoustic approach eliminates the charging complexity while maintaining effective noise attenuation.
Solution Approach 2:
The patent changes the physical parameters of the earplug by incorporating specific cavity volumes, damping material densities, and passage geometries optimized for high-frequency noise attenuation. By adjusting these acoustic parameters in the metasurface structure, the device achieves superior noise reduction performance in the high-frequency range without requiring electronic systems.
2Ease of manufacture
If conventional sound absorbing materials are used, then manufacturing cost is reduced, but high-frequency noise reduction effectiveness deteriorates
Solution Approach 1:
The patent employs a composite acoustic metasurface structure combining multiple materials with different acoustic properties. This includes damping materials (such as foam or rubber) integrated with rigid cavity structures and specific passage geometries. The composite design leverages the sound absorption characteristics of damping materials while the cavity resonators provide targeted high-frequency attenuation, achieving superior performance compared to conventional single-material approaches.
Solution Approach 2:
The earplug is segmented into distinct functional zones: an eartip portion, a connecting tube, and an interference attenuation module containing the metasurface structure. The attenuation module itself is divided into multiple cavity resonators and damping sections. This segmentation allows each component to be optimized for its specific function while maintaining overall cost-effectiveness through modular manufacturing.
3Object-affected harmful factors
If all bands of sound are blocked, then noise protection is improved, but communication capability deteriorates
Solution Approach 1:
The acoustic metasurface is designed with local variations in cavity volumes, passage cross-sections, and damping material distribution to create frequency-selective attenuation. The structure provides strong attenuation in high-frequency noise bands while maintaining transparency or reduced attenuation in lower frequency ranges where speech and communication signals reside. This local quality variation enables simultaneous noise protection and communication capability.
Solution Approach 2:
The patent incorporates porous damping materials with specific flow resistance characteristics within the metasurface structure. These porous materials selectively attenuate high-frequency noise through viscous losses while allowing lower frequency sound waves to pass through with minimal attenuation. The pore size, distribution, and material composition are optimized to achieve the desired frequency-dependent transmission characteristics that preserve communication while blocking noise.
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 earplug effectively attenuates high-frequency noise while allowing low-frequency sounds, such as voices, to pass through, thereby improving communication and reducing hearing loss without the need for charging.
Implementation Method 1
a first reflective cavity that is connected to the damping passage and reflects incident sound waves and transmits the sound waves to the damping passage
Implementation Method 2
the phase-shifted noise interferes with the noise incident in the damping passage, thus the high-frequency noise can be attenuated by interference
Implementation Method 3
an interference attenuation module having a damping passage for reducing noise
Data Source
AI summary
Proposed is an earplug that can effectively reduce high-frequency noise using a metasurface. The high-frequency noise filtering earplug using a metasurface according to an embodiment of the present disclosure may include an eartip with an internal passage, an interference attenuation module having a damping passage for reducing noise and a first reflective cavity that is connected to the damping passage and reflects incident sound waves and transmits the sound waves to the damping passage, and a connecting tube installed between the eartip and the interference attenuation module to connect the internal passage and the damping passage to each other.