3D Air-Adsorbing Structure for Loudspeaker Humidity Resistance

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Solution Overview

Problem

Conventional air-adsorbing materials in loudspeaker systems are ineffective in humid environments and require cumbersome humidity control systems, as they degrade under moisture exposure, limiting their air-adsorption capacity and compliance.

Innovation Solution

A three-dimensional air-adsorbing structure comprising a skeletal, porous scaffold with hydrophobic binder and air-adsorbing material particles, where the scaffold openings make up at least 50% of the volume, allowing air to reach the material at frequencies above 40 Hz, and the binder inhibits moisture retention to maintain air-adsorption capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional air-adsorbing materials are used in loudspeaker enclosures, then air compliance is improved, but the materials degrade under moisture exposure and require cumbersome humidity control systems

Engineering Contradiction:
Improveair-adsorption capacityVSAvoidhumidity control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies hydrophobic binder materials that specifically repel moisture while allowing air molecules to be adsorbed. This converts the harmful effect of moisture into a beneficial selective adsorption property, where the binder protects the air-adsorbing material from water damage while maintaining its air compliance function, eliminating the need for humidity control systems

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The invention creates a composite structure combining air-adsorbing material particles with hydrophobic binder materials. This composite formulation integrates the air compliance enhancement capability of the adsorbing material with the moisture resistance of the hydrophobic binder, achieving both improved air compliance and humidity resistance in a single integrated component

Inventive Principle:
Principle #40Composite materials

2Volume of stationary object

If air-adsorbing material is packaged to occupy small volume, then space efficiency is improved, but air access to the material is restricted at low frequencies

Engineering Contradiction:
Improveadsorbent volumeVSAvoidair access speed
Core Design Contradiction:
Volume of stationary objectVSSpeed

Solution Approach 1:

The patent employs a porous scaffold structure with controlled pore size distribution that allows air molecules to penetrate and access the air-adsorbing material particles embedded within. The porous architecture provides multiple access pathways, ensuring that even at low frequencies where air movement is slower, air can still reach the adsorption sites effectively while maintaining a compact overall structure

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The invention creates local variations in pore size and material distribution within the adsorbent structure. Larger pores are positioned to facilitate air entry and circulation, while smaller pores provide high-surface-area adsorption zones. This local differentiation optimizes both air access and adsorption efficiency within a compact volume

Inventive Principle:
Principle #3Local quality

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 long-term increased air compliance without the need for humidity control systems, maintaining air-adsorption capacity even in humid conditions, enhancing low-frequency sound reproduction in loudspeaker systems.

Implementation Method 1

a hydrophobic binder that couples air-adsorbing material particles to each other to form agglomerates and couples particles and agglomerates to the scaffold

Methodology Applied
Scientific EffectHydrophobic effect: Hydrophobe

Implementation Method 2

the adsorption properties of the material should not degrade or change significantly when exposed to different environmental conditions

Methodology Applied
Scientific EffectPhysical adsorption: Adsorption

Data Source

PatentEP2970623B1Three-dimensional air-adsorbing structure
Publication Date: 2017.12.27 BOSE CORP
  • EP2970623B1 patent drawingFigure 1
  • EP2970623B1 patent drawingFigure 2
  • EP2970623B1 patent drawingFigure 3A

AI summary

A three-dimensional air-adsorbing structure for use in a volume in which there is a time-varying acoustic field. The structure has a three-dimensional, unitary, skeletal, porous scaffold having scaffold openings distributed within its volume, where the scaffold openings make up at least about 50% of the volume of the scaffold, air-adsorbing material particles, and a hydrophobic binder that couples air-adsorbing material particles to each other to form agglomerates and couples particles and agglomerates to the scaffold. The structure has structure openings in the agglomerates and structure openings between agglomerates, such structure openings being open to the outside environment, wherein the cumulative volume of the structure openings that have an apparent diameter larger than about 0.01 microns as measured by mercury porosimetry is at least about 40% of the volume of the air-adsorbing structure, and the cumulative volume of the structure openings that have an apparent diameter larger than about 5 microns as measured by mercury porosimetry is at least about 15% of the volume of the air-adsorbing structure.