Membrane Soundproof Structure for High-Frequency Noise Reduction
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Solution Overview
Problem
Existing soundproof structures fail to effectively reduce noise with high natural frequencies generated by electronic apparatuses, as they either require large amounts of porous sound absorbing materials, which are difficult to accommodate in compact devices, or rely on membrane vibration methods that have low sound absorption coefficients at high frequencies and are sensitive to environmental changes.
Innovation Solution
A soundproof structure incorporating a membrane-like member supported to perform membrane vibration, with a rear surface space on one side, where the sound absorption coefficient at high-order vibration modes (above 1 kHz) is higher than at fundamental vibration modes, and specific design parameters such as Young's modulus, thickness, and rear surface space dimensions are optimized to enhance sound absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a porous sound absorbing body is used to reduce noise, then a sound reduction effect is obtained in a wide frequency range, but noise with a natural frequency of the sound source is not sufficiently reduced and the sound at a specific frequency becomes more audible
Solution Approach 1:
The patent applies local quality by using a membrane structure that provides targeted sound absorption at specific frequencies (natural frequencies of sound sources) rather than uniform absorption across all frequencies. The membrane's vibration characteristics are specifically tuned to address the problematic frequency bands where sound sources operate, creating localized effectiveness where needed most.
Solution Approach 2:
The patent utilizes mechanical vibration through a membrane structure that vibrates in response to sound waves. The membrane's vibration absorbs sound energy at specific frequencies through its natural vibration modes, providing effective noise reduction at the natural frequencies of sound sources while maintaining versatility across different frequency ranges.
2Reliability
If a large amount of porous sound absorbing body is used to reduce louder sound, then sound reduction effectiveness improves, but the electronic apparatus cannot be reduced in size and weight
Solution Approach 1:
The patent employs a thin membrane structure that provides effective sound absorption without requiring large volumes of porous material. The membrane's flexible nature allows it to vibrate and absorb sound energy at specific frequencies, achieving the required sound reduction effectiveness while maintaining a compact and lightweight design suitable for electronic apparatus.
Solution Approach 2:
The membrane structure utilizes mechanical vibration to absorb sound energy efficiently. By tuning the membrane's vibration characteristics to match the natural frequencies of sound sources, the system achieves high sound reduction effectiveness with minimal material quantity, thereby reducing overall apparatus weight.
3Weight of moving object
If membrane vibration is used to reduce sound at a specific frequency, then the structure becomes small and light, but the sound absorption coefficient at high frequencies is low and the structure is sensitive to environmental changes
Solution Approach 1:
The patent applies parameter changes by optimizing the membrane's physical characteristics (thickness, material properties, tension) to tune its vibration frequency and sound absorption properties. By carefully selecting and adjusting these parameters, the membrane achieves high sound absorption coefficients at high frequencies while maintaining a lightweight structure and reduced sensitivity to environmental variations.
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 structure achieves efficient noise reduction at high frequencies while being robust against environmental changes, maintaining effectiveness in compact and lightweight designs.
Implementation Method 1
a sound is reduced due to vibration of the membrane-like member
Implementation Method 2
a sound absorption coefficient of the vibration of the membrane-like member at a frequency in at least one high-order vibration mode existing at frequencies of 1 kHz or higher is higher than a sound absorption coefficient at a frequency in a fundamental vibration mode
Data Source
AI summary
Provided is a soundproof structure that is small and light and can sufficiently reduce noise with a high natural frequency of a sound source. There is provided a soundproof structure including a frame having an opening, and at least one membrane-like member fixed to an opening surface where the opening of the frame is formed, in which a rear surface space is formed to be surrounded by the frame and the membrane-like member, and a sound is absorbed due to vibration of the membrane-like member, and a sound absorption coefficient of the vibration of the membrane-like member at a frequency in at least one high-order vibration mode existing at frequencies of 1 kHz or higher is higher than a sound absorption coefficient at a frequency in a fundamental vibration mode.