UD Fiber Membrane Plate for Micro-Speaker Stiffness
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Solution Overview
Problem
Micro-speakers require thin membrane plates with high resonance frequency, low weight, and high temperature resistance to reduce size and improve sound pressure levels, but existing materials struggle to achieve these characteristics, especially at thicknesses below 500 μm and weights under 160 g/m2, while also needing non-conductive options.
Innovation Solution
A membrane plate structure using thin Uni-Directional (UD) fiber tape oriented along the shorter size of the plate, integrated into a sandwich construction with a polymer matrix, offering higher break-up frequencies and lower weights, and featuring a core layer that can be pore-free or porous, with fibers like aramid or carbon for enhanced mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If thin membrane plates are used to reduce speaker size, then the overall loudspeaker size is reduced, but the resonance frequency decreases and mechanical stiffness is compromised
Solution Approach 1:
The patent employs sandwich composite construction with fiber-reinforced polymer skins (UD or multi-axial) and foam core, achieving high mechanical stiffness and resonance frequency (above 20 kHz) in thin membrane plates (0.2-0.5 mm thickness), thus reducing loudspeaker size while maintaining structural integrity
Solution Approach 2:
The membrane plate uses localized fiber orientation patterns with different ply configurations in different regions (e.g., 0/45/-45/90 degrees) to optimize stiffness distribution, providing higher stiffness where needed while keeping overall thickness minimal
2Volume of moving object
If thin membrane plates are used to reduce speaker size, then the overall loudspeaker size is reduced, but the weight reduction is insufficient to improve sound pressure level
Solution Approach 1:
The sandwich composite structure with lightweight foam core (10-30 kg/m³ density) and thin fiber-reinforced skins achieves areal density between 30-80 g/m², providing sufficient stiffness while minimizing weight to improve sound pressure level and efficiency
3Strength
If conventional multi-ply fiber composites are used to increase stiffness, then the stiffness in both directions is improved, but the weight exceeds 160 g/m2
Solution Approach 1:
The optimized sandwich composite with thin UD or multi-axial fiber skins (total thickness 0.2-0.5 mm) and lightweight foam core achieves the required stiffness-to-weight ratio with areal density between 30-80 g/m², well below the 160 g/m² threshold while maintaining high break-up frequency
4Speed
If aluminum foil skin layers are used in sandwich construction to achieve high frequency factor, then the mechanical performance is improved, but the material becomes conductive
Solution Approach 1:
The patent replaces conductive aluminum foil skins with non-conductive fiber-reinforced polymer composite skins (UD or multi-axial configurations) in the sandwich structure, achieving comparable or superior mechanical performance with high break-up frequency while providing electrical insulation, suitable for applications requiring non-conductive materials
Data Source
AI summary
The present invention relates to a membrane plate structure for generating sound waves, the membrane plate structure comprises a vibrating element for generating sound waves and a membrane plate which is coupleable to the vibrating element. The membrane plate has a different width with respect to its length, wherein the width is shorter than the length. The membrane plate comprises an UD layer made of fibers, wherein the fibers of the UD layer are oriented along the width of the membrane plate.