Glass Sheet Composite Diaphragm for Loudspeaker High-Frequency Reproduction
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Solution Overview
Problem
Conventional diaphragms for loudspeakers and microphones face challenges in reproducing high-frequency sounds due to low acoustic velocity and high loss coefficient, leading to poor sound pressure output and resonant vibration issues.
Innovation Solution
A glass sheet composite is developed with a loss coefficient of 1×10−2 or more and a longitudinal wave acoustic velocity of 5.5×103 m/s or more, comprising two or more glass sheets with a liquid layer between them, where the liquid layer has specific viscosity and surface tension properties, and the glass sheets have a mass ratio and resonant frequency relationship that enhances vibration damping and sound reproduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional materials like paper or resin are used as diaphragms, then the loss coefficient is high which prevents resonant vibration, but the acoustic velocity is low making it difficult to reproduce high-frequency sounds with desired sound pressure
Solution Approach 1:
The patent uses a composite structure consisting of a glass sheet and a resin layer. The glass sheet provides high acoustic velocity (5200 m/s or more) for high-frequency sound reproduction, while the resin layer provides high loss coefficient for vibration damping. This composite material approach resolves the contradiction by combining materials with complementary properties.
2Speed
If metal, ceramic or glass materials with high acoustic velocity are used, then high-frequency sound reproduction is improved, but the loss coefficient is low causing unintended reverberant sound and resonant modes
Solution Approach 1:
The patent combines glass sheet (high acoustic velocity) with resin layer (high loss coefficient) to create a composite diaphragm that simultaneously achieves high-frequency sound reproduction capability and vibration damping to prevent reverberant sound and resonant modes.
Solution Approach 2:
The resin layer is applied specifically to the back surface of the glass sheet where vibration damping is most needed, while maintaining the glass sheet's high acoustic velocity properties in the sound transmission path. This localized application optimizes both properties in their respective functional zones.
3Loss of energy
If a polybutyl polymer layer is used between glass sheets, then vibration damping is improved, but reproduction in high-frequency region becomes difficult
Solution Approach 1:
The patent specifies precise parameter ranges for the resin layer including thickness (0.01-0.5 mm), loss coefficient (0.05 or more), and acoustic velocity (2000-4000 m/s). By optimizing these parameters, the resin layer provides sufficient vibration damping while the overall structure maintains high-frequency reproduction capability through the glass sheet's high acoustic velocity (5200 m/s or more).
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 glass sheet composite improves sound reproducibility across a wide frequency range, reduces resonance, and enhances vibration control, making it suitable for applications in loudspeakers, microphones, and magnetic recording mediums.
Implementation Method 1
a liquid layer between at least a pair of glass sheets out of the glass sheets
Implementation Method 2
a longitudinal wave acoustic velocity in a sheet thickness direction of 5.5×103 m/s or more
Data Source
AI summary
A glass sheet composite having two or more glass sheets and a liquid layer between at least a pair of glass sheets out of the glass sheets, wherein a thickness of the liquid layer is 1/10 or less of a total thickness of the pair of glass sheets when a total thickness of the pair of glass sheets is 1 mm or less, and 100 μm or less when the total thickness of the pair of glass sheets is more than 1 mm.