Electret Speaker Structure for Miniaturization and Mass Production
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Solution Overview
Problem
Conventional speaker structures, particularly dynamic and electrostatic speakers, face challenges in being miniaturized and flattened to meet the trend of 3C products becoming lighter and thinner, with issues of significant distortion, high power requirements, and complex designs that hinder mass production and flexibility.
Innovation Solution
A speaker structure utilizing a single electret vibrating film with a metal electrode having multiple holes and a frame supporting member, made of flexible and transparent materials, which reduces the audio voltage required and prevents oxidation effects, allowing for simpler construction and mass production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dynamic speaker is used to achieve mature technology and wide usage, then reliability is improved, but volume cannot be flattened and weight cannot be reduced
Solution Approach 1:
The patent replaces the traditional dynamic speaker mechanical system (voice coil, magnet, diaphragm) with an electrostatic system consisting of a flexible substrate, electret film, and electrode patterns. This substitution eliminates the need for bulky magnetic components, enabling the speaker to be flattened and miniaturized while maintaining functional reliability through electrostatic actuation principles.
Solution Approach 2:
The patent employs a flexible substrate with electret film and thin electrode patterns to create a flattened speaker structure. The flexible substrate allows the speaker to conform to various surfaces and reduces overall volume, while the thin film construction maintains acoustic performance without requiring traditional rigid mechanical components.
2Volume of moving object
If piezoelectric speaker is used to flatten and miniaturize structure, then volume is reduced, but significant distortion and instability occur
Solution Approach 1:
The patent changes the actuation mechanism from piezoelectric material deformation to electrostatic force between charged surfaces. By using an electret film with fixed charge and applying AC voltage to electrode patterns, the system achieves larger, more stable diaphragm movements without the significant distortion characteristic of piezoelectric speakers, while maintaining the flattened structure.
3Power
If conventional electrostatic speaker is used to achieve high sound pressure, then sound pressure output is improved, but high voltage power supply and complex structure are required
Solution Approach 1:
The patent merges the electret film and flexible substrate into a single integrated vibrating film assembly, and integrates electrode patterns directly onto the substrate. This consolidation eliminates separate components for vibration generation and electrical connection, reducing structural complexity while maintaining high sound pressure output through efficient electrostatic coupling.
Solution Approach 2:
The patent uses a flexible substrate as both the structural support and the mounting platform for electrode patterns, eliminating the need for rigid frames and complex mounting structures. This flexible film approach simplifies the overall device structure while enabling efficient sound pressure generation through direct electrostatic actuation of the vibrating film.
4Reliability
If metal thin film electrode is used in vibrating film structure, then electrical conductivity is improved, but oxidation effect affects sound source signal input
Solution Approach 1:
The patent employs a composite structure where the flexible substrate serves as both mechanical support and electrical insulation, while metal electrode patterns are deposited on the substrate surface. The substrate acts as a protective barrier preventing oxidation of the metal electrodes, while the metal patterns provide the necessary electrical conductivity for signal input and electrostatic actuation.
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 speaker structure achieves high sound-pressure output with reduced complexity and flexibility, enabling it to meet the demands of modern 3C products while maintaining sound quality and being suitable for mass production.
Implementation Method 1
the operating principle for the conventional electrostatic speaker is that two fixed electrode plates with holes are used to clamp a conductive vibrating film to form a capacitor, and then a DC bias is applied to the vibrating film and an AC voltage is applied to two fixed electrodes, and electrostatic force generated by the positive and negative electric fields is used to drive the conductive vibrating film to vibrate and to radiate sounds
Implementation Method 2
The electret vibrating film structure is formed by a single electret film layer, a metal thin film electrode, and an isolation layer stacked together
Data Source
AI summary
A speaker structure including a single electret vibrating film structure, a single metal electrode with a plurality of holes and a frame supporting member is provided. In an example, the electret vibrating film structure is formed by an electret film layer, an ultra-thin metal thin film electrode and an isolation layer stacked together, in which the ultra-thin metal thin film electrode is located between the electret film layer and the isolation layer. In another example, the electret vibrating film structure is formed by the electret film layer and a conductive electrode layer having oxide conductive materials. The frame supporting member is located between the electret vibrating film structure and the metal electrode for forming a space for the vibration of the electret vibrating film structure, so as to generate sounds.