Freeze-Dried Sound-Absorbing Sheet for Speaker Rear Cavities
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Solution Overview
Problem
Existing sound-absorbing materials in speaker rear cavities face issues such as peeling, crushing, and poor acoustic performance due to particle collision and static electricity, leading to inefficient use of space and compromised audio quality.
Innovation Solution
A sound-absorbing sheet with a sheet body created by mixing sound-absorbing powder, binder, thickening agent, and foaming agent, coated and freeze-dried to form needle-like pores, and attached to a bonding layer for enhanced stability and sound absorption, allowing for flexible design and improved acoustic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If sound-absorbing particle material is added in the rear cavity of the speaker, then the rear cavity is enlarged virtually, but the particle material is prone to peeling and crushing due to mutual collision and friction
Solution Approach 1:
The patent uses a sheet-like sound-absorbing structure with flexible binder materials to create a stable, integrated filling that eliminates particle collision and friction while maintaining rear cavity volume expansion
Solution Approach 2:
The patent creates a composite sound-absorbing sheet combining sound-absorbing powder particles embedded in a binder matrix, integrating the benefits of particle materials with structural stability to prevent peeling and crushing
2Volume of stationary object
If sound-absorbing particle material is used, then the rear cavity can be filled, but static electricity caused by friction prevents thorough filling and utilization of space
Solution Approach 1:
The binder material in the composite sheet structure eliminates static electricity generation by preventing particle-to-particle friction, while still allowing complete filling of the rear cavity space
3Reliability
If sound-absorbing bulk material is added into the rear cavity of the speaker, then the strength and stability are improved, but the acoustic performance is poor compared to particle material
Solution Approach 1:
The patent optimizes the local properties of the sound-absorbing sheet by controlling pore size distribution, sheet thickness, and binder content to achieve both high strength/stability and superior acoustic performance simultaneously
Solution Approach 2:
The sheet structure incorporates controlled porosity to maintain sound absorption capabilities while providing the structural integrity of bulk materials
4Strength
If sound-absorbing bulk material is used, then the strength is improved, but the surface morphology changes due to friction with the cavity, affecting performance
Solution Approach 1:
The sheet-like structure with flexible binder provides resistance to friction-induced morphology changes while maintaining strength, preventing surface degradation in the rear cavity environment
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-absorbing sheet provides high sound absorption and low damping performance, maintaining structural integrity and reducing aging risks, thus enhancing audio quality and adaptability to various speaker designs.
Implementation Method 1
the sheet body is prepared by coating and freeze-drying a slurry
Implementation Method 2
the slurry is obtained by mixing sound-absorbing powder, a binder, a thickening agent and a foaming agent with a solvent; the sheet body has needle-like pores with a pore size of 1 μm-100 μm
Data Source
AI summary
A sound-absorbing material, a manufacturing method thereof and a speaker are provided. The sound-absorbing sheet includes a sheet body and a bonding layer. The sheet body is prepared by coating and freeze-drying a slurry, and the slurry is obtained by mixing sound-absorbing powder, a binder, a thickening agent and a foaming agent with a solvent. The sheet body has thickness of 0.05 mm-2 mm; the sheet body has needle-like pores with a pore size of 1 μm-100 μm. The bonding layer is configured to fixedly install the sound-absorbing sheet. By needle-like pores, the sound-absorbing sheet has high sound absorption performance, and low damping performance. The sheet can be designed into different shapes and thicknesses for rear cavities of different speakers, so the application range is wide. Because of bonding layer, while aging risk of a structure in the speaker is lowered, the sound-absorbing sheet has higher strength.