Temperature Stable Loudspeaker Membrane Plate Structure
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Solution Overview
Problem
Micro-speakers for portable devices require thinner elements to reduce size while maintaining high temperature resistance and mechanical stiffness, which is challenging due to the limitations of available thickness and material properties.
Innovation Solution
A membrane plate structure comprising a first skin layer, a second skin layer, a foam core layer, and binding layers, where the Young modulus and density of the core layer are lower than the skin layers, and the material maintains mechanical properties up to 180°C, allowing for non-planar geometry and high temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the membrane plate thickness is reduced to minimize loudspeaker size, then the overall device size is reduced, but the mechanical stiffness and temperature resistance deteriorate
Solution Approach 1:
The patent employs a sandwich construction with multiple layers: thin outer skin layers (aluminum or polymer) provide stiffness while the foam core layer provides structural support and thermal insulation. This composite structure achieves high mechanical stiffness and temperature resistance despite the overall thin profile, resolving the contradiction between size reduction and strength maintenance
Solution Approach 2:
The patent applies different material properties to different regions: the outer skin layers use high-stiffness materials (aluminum or rigid polymer) for structural integrity, while the inner core uses lightweight foam for support and thermal management. This localized material differentiation allows the thin membrane plate to maintain strength and temperature resistance throughout its structure
2Area of moving object
If high-performance materials are used to achieve high frequency factors in thin membranes, then the material resonance frequency increases, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent divides the membrane plate into discrete layers (outer skins and core) that can be manufactured separately using standard industrial processes, then bonded together. This segmentation allows each layer to be optimized independently for frequency performance while maintaining ease of manufacturing through modular assembly
Solution Approach 2:
The patent optimizes the thickness and material composition parameters of each layer to achieve the desired frequency factor. By carefully selecting skin layer thickness (1-10 μm) and core layer properties, the design achieves high material resonance frequency while using commercially available materials and manufacturing processes
3Weight of moving object
If the membrane plate is made thinner to reduce weight, then the sound pressure level and efficiency increase, but the temperature stability deteriorates
Solution Approach 1:
The sandwich construction with foam core provides thermal insulation between the outer skin layers, reducing heat transfer and improving temperature stability. The thin outer skins minimize weight while the core layer acts as a thermal barrier, resolving the contradiction between weight reduction and temperature stability
Solution Approach 2:
The foam core layer acts as an intermediary between the outer skin layers, providing thermal insulation and mechanical support. This intermediate layer prevents direct thermal coupling between the skins, maintaining temperature stability while allowing the overall structure to remain thin and lightweight
Data Source
AI summary
The present invention relates to a membrane plate structure for generating sound waves. The membrane plate structure comprises a first skin layer, a second skin layer, a foam core layer which is interposed between the first skin layer and the second skin layer, and two binding layers. At least one of the first skin layer and the second skin layer is attachable to a vibrating element for generating sound waves. The elastic modulus of the core layer and its density are lower than the elastic modulus and the density of the first skin layer and the second skin layer, so that a sandwich structure is achieved. The Young modulus and the shear modulus of first skin layer, the second skin layer, the core layer and the binding layers are not variating between each other of more than 30% between a temperature 20° C. and 150° C., particularly between 20° C. and 170° C., more particularly 20° C. and 180° C.