Thermoformable Microspeaker Diaphragm with Cross-Linked Polyester Elastomer
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Solution Overview
Problem
Existing microspeaker diaphragms face challenges in achieving high rigidity, strength, resilience, and damping properties, with materials like thermoplastic elastomers lacking thermal stability and fatigue resistance, and multi-layer films having poor elasticity and small amplitude.
Innovation Solution
A chemically cross-linked thermoplastic polyester elastomer diaphragm with a loss factor less than 0.4 and yield strain between 7% to 30%, manufactured via electron beam radiation, ensuring thermal stability and mechanical properties suitable for microspeakers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single-layer plastic film (PP, PET, PI, PEN, PEEK) is used for the diaphragm, then high rigidity and thermal stability are achieved, but damping properties are insufficient and frequency response is not smooth
Solution Approach 1:
The patent applies composite materials by combining a plastic film layer with a thermoplastic elastomer layer to create a multi-layer diaphragm structure. The plastic film provides rigidity and thermal stability, while the thermoplastic elastomer layer contributes damping properties and resilience, thereby resolving the contradiction between rigidity and damping performance.
2Temperature
If the glass transition temperature Tg of the diaphragm material is increased to maintain high rigidity, then thermal stability is improved, but the difficulty of thermoforming process increases
Solution Approach 1:
The patent uses a composite structure where the plastic film layer provides the necessary thermal stability through its high glass transition temperature, while the thermoplastic elastomer layer has lower processing temperature requirements, thereby facilitating the thermoforming process and reducing manufacturing difficulty.
3Reliability
If a multi-layer film structure with damping adhesive layer is used, then damping properties and frequency response smoothness are improved, but elasticity is reduced and applicable amplitude is small
Solution Approach 1:
The patent changes the material parameters by selecting a thermoplastic elastomer with specific properties (loss factor less than 0.4, yield strain between 7-30%) that provides both damping capability and high elasticity. This allows the diaphragm to achieve large vibration amplitudes while maintaining smooth frequency response, resolving the contradiction between damping and elasticity.
4Strength
If thermoplastic elastomer material is used for the diaphragm, then resilience performance and amplitude are improved, but fatigue resistance and high temperature resistance are poor
Solution Approach 1:
The patent creates a composite structure where the thermoplastic elastomer layer provides resilience and allows large amplitude vibration, while the plastic film layer provides structural support and improves fatigue resistance. The combination enables the diaphragm to maintain high resilience performance while achieving acceptable fatigue and temperature resistance.
5Reliability
If a multi-layer composite film structure is used to improve damping, then sound quality is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies composite materials in a practical manufacturing way by using a multi-layer structure of plastic film and thermoplastic elastomer that can be processed together through thermoforming. This approach achieves improved sound quality with damping properties while keeping the manufacturing process relatively simple and suitable for industrial production.
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 diaphragm achieves improved thermal stability, strength, and elasticity, facilitating high amplitude vibration and sound quality, while maintaining consistency over a wide frequency range.
Implementation Method 1
the chemically cross-linked thermoplastic polyester elastomer has a loss factor less than or equal to 0.4 at a temperature range not higher than a softening temperature of thermoplastic polyester elastomer before chemical crosslinking plus 40° C., as measured by a rheological curve
Implementation Method 2
manufactured via electron beam radiation, ensuring thermal stability and mechanical properties suitable for microspeakers
Data Source
AI summary
The invention provides a diaphragm for a microspeaker and a manufacturing method thereof. The diaphragm is a single-layer diaphragm or a multi-layer diaphragm and comprises at least one layer of a chemically cross-linked thermoplastic polyester elastomer, wherein: the chemically cross-linked thermoplastic polyester elastomer has a loss factor less than or equal to 0.4 at a temperature range not higher than a softening temperature of thermoplastic polyester elastomer before chemical crosslinking plus 40° C., as measured by a rheological curve; and the diaphragm further has a yield strain in the range of 7% to 30%. The diaphragm for a microspeaker according to the technical solution of the present invention is easy to be prepared by thermoforming, and has appropriate modulus, good strength, elasticity, and thermal stability.