Diaphragm Orientation Dispersion Structure Suppresses High Frequency Resonance Peaks

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Solution Overview

Problem

Acoustic apparatuses, such as speakers, face challenges in suppressing the sharpening of resonance peaks in the high frequency range, particularly with diaphragms having highly symmetric shapes, which can lead to complex manufacturing issues and generation of new resonance modes.

Innovation Solution

The diaphragm is designed with an orientation dispersion structure, providing anisotropic mechanical strength by dispersing shape-anisotropic fillers in a thermoplastic resin, allowing for a seamless sheet member with high-rigidity and low-rigidity regions, maintaining continuous rotational symmetry while dispersing resonance frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a diaphragm with highly symmetric shape (continuous rotation symmetry) is used, then manufacturing is simplified, but sharp resonance peaks appear in the high frequency range

Engineering Contradiction:
Improveease of manufactureVSAvoidsharp resonance peak
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent applies asymmetry by dispersing shape-anisotropic fillers (such as fibers or plate-like particles) in specific directions within the diaphragm material. This creates directional differences in mechanical properties without changing the overall symmetric shape of the diaphragm, thereby suppressing sharp resonance peaks while maintaining ease of manufacture.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent implements local quality by varying the orientation and distribution of shape-anisotropic fillers in different regions of the diaphragm. This creates localized differences in rigidity and damping characteristics, allowing suppression of resonance peaks in specific frequency ranges while maintaining the overall symmetric shape and manufacturing simplicity.

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If the shape symmetry is decreased (e.g., oblique-cone or modified sectional shape) to suppress resonance peak sharpening, then sharp resonance peaks are suppressed, but manufacturing complexity increases and new resonance modes are generated

Engineering Contradiction:
Improvesharp resonance peakVSAvoidshape complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

Instead of changing the macroscopic symmetric shape, the patent introduces microscopic asymmetry through the directional arrangement of shape-anisotropic fillers. This allows suppression of resonance peak sharpening while maintaining the simple symmetric overall shape, avoiding increased manufacturing complexity and new resonance modes.

Inventive Principle:
Principle #4Asymmetry

3Reliability

If composite materials with high specific modulus of longitudinal elasticity are used, then frequency characteristics in a wide band are improved, but sharp resonance peaks appear in the high range

Engineering Contradiction:
Improvefrequency characteristicsVSAvoidsharp resonance peak
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent uses composite materials consisting of a base material (such as resin or metal) reinforced with shape-anisotropic fillers (fibers or plate-like particles). This provides wide band frequency characteristics through the composite structure while the directional arrangement of fillers suppresses sharp resonance peaks.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Within the composite material structure, the patent introduces directional asymmetry by orienting shape-anisotropic fillers in specific directions. This creates anisotropic mechanical properties that suppress resonance peak sharpening in the high frequency range while maintaining the wide band frequency characteristics provided by the composite structure.

Inventive Principle:
Principle #4Asymmetry

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

This approach effectively suppresses sharp resonance peaks in the high frequency range, maintains good acoustic characteristics, and simplifies manufacturing, avoiding defects in frequency characteristics of sound pressure.

Implementation Method 1

The sheet member has an orientation dispersion structure in which shape-anisotropic fillers are dispersed in a thermoplastic resin

Methodology Applied
Scientific EffectAnisotropy: Anisotropy

Data Source

PatentEP3355589B1Acoustic apparatus
Publication Date: 2023.05.24 ALPINE ELECTRONICS INC
  • EP3355589B1 patent drawingFigure 1A~1B
  • EP3355589B1 patent drawingFigure 2A~2B
  • EP3355589B1 patent drawingFigure 3

AI summary

An acoustic apparatus includes a frame having an annular open portion that opens in an axial direction; a diaphragm supported by being attached to the annular open portion via a flexible edge member so as to be capable of vibrating in the axial direction; and a driving unit connected to the diaphragm at a center portion of the diaphragm, and configured to apply a driving force in the axial direction to the diaphragm. The diaphragm has a rotationally symmetric shape around an axis of the diaphragm when viewed in the axial direction. The diaphragm includes a sheet member having an orientation dispersion structure in which shape-anisotropic fillers are dispersed in a resin with long axes of the fillers oriented in one predetermined direction, and the diaphragm has mechanical characteristics having two-fold rotation symmetry around the axis.