Projector Sound Absorber Low-Frequency Noise Reduction
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Solution Overview
Problem
Existing projector cooling systems face challenges in effectively reducing noise, particularly in the low-frequency band, due to insufficient absorption capabilities of traditional silencers, as noise in this range is predominantly harmonic and difficult to attenuate with current designs.
Innovation Solution
A sound absorber configuration comprising a first wall section with thin film, a second wall section, and a porous material, forming multiple sound absorbing sections that work together to absorb sound waves across a wide frequency band, particularly in the low-frequency range of 500 to 1,000 Hz, by utilizing a combination of thin film vibration, space propagation, and porous material absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional silencers are used, then high-frequency noise is absorbed, but low-frequency noise remains insufficiently absorbed
Solution Approach 1:
The silencer is divided into multiple sound absorbing sections (first, second, and third sections) with different structures and materials. Each section targets specific frequency ranges, with the first section handling higher frequencies and the second and third sections addressing low-frequency noise through porous materials and resonance box configurations.
Solution Approach 2:
The silencer employs composite structures combining different materials and mechanisms: thin films for vibration absorption, porous materials for low-frequency sound absorption, and resonance box sections for harmonic noise reduction. This composite approach enables effective noise absorption across a wide frequency band from 100 Hz to 10,000 Hz.
2Object-affected harmful factors
If multiple Helmholtz silencers are used to reduce harmonic noise, then noise reduction is achieved, but the structure becomes complex
Solution Approach 1:
Multiple sound absorbing functions are merged into a single integrated silencer structure. The first, second, and third sound absorbing sections are combined in one device, eliminating the need for multiple separate Helmholtz silencers while achieving the same harmonic noise reduction effect.
Solution Approach 2:
The silencer is designed as a multi-functional device that simultaneously performs high-frequency noise absorption, low-frequency noise absorption, and harmonic noise reduction through its different sections, replacing the need for multiple specialized silencers.
3Power
If cooling fan power is increased to handle higher heat generation, then cooling performance improves, but noise in the low sound range increases
Solution Approach 1:
Porous materials are used in the second and third sound absorbing sections to effectively absorb low-frequency noise generated by high-power cooling fans. The porous structure dissipates sound energy through friction and viscous effects, reducing the noise impact of increased fan power.
Solution Approach 2:
The silencer converts the harmful low-frequency noise generated by high-power cooling fans into beneficial sound absorption through its specially designed second and third sound absorbing sections, allowing the system to operate at higher power levels without excessive 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 sound absorber significantly reduces noise in the low-frequency band, effectively addressing the limitations of existing technologies by providing a conspicuous noise reduction in projectors, particularly in the frequency range easily sensed by humans, while maintaining a simple and easily manufacturable design.
Implementation Method 1
a first sound absorbing section configured by the first wall section to which the thin film is stuck and a space between the first wall section and the second wall section
Implementation Method 2
a third sound absorbing section configured by the porous material
Implementation Method 3
The Helmholtz silencers are configured from neck sections and resonance box sections
Data Source
AI summary
A sound absorber includes a side surface section (a first wall section) in which a plurality of first holes are provided, the side surface section including a first surface and a second surface, a thin film stuck to the first surface of the side surface section, a partition wall (a second wall section) opposed to the second surface and provided in a position separated from the second surface, at least one second hole being provided in the partition wall, and a porous material provided to be opposed to the second wall section in a position separated from the partition wall.