Electroactive Film Speaker with Concave Structures for Flexible Displays
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Solution Overview
Problem
Conventional voice coil diaphragm speakers are limited in weight reduction, flexibility, and transparency, making them unsuitable for flexible and transparent display devices, and they cannot be easily integrated into thin, bendable, or transparent forms due to their opaque nature and thickness constraints.
Innovation Solution
A film speaker utilizing an electroactive layer with concave portions and electrodes on its surfaces, enhancing sound pressure levels by optimizing the concave and convex structures to amplify sound and improve flexibility and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a voice coil diaphragm speaker is used, then sound output is achieved, but weight reduction is limited and flexibility cannot be implemented
Solution Approach 1:
The patent replaces the traditional voice coil motor (electromagnetic mechanical system) with an electroactive polymer layer that directly converts electrical energy to mechanical vibration. This substitution eliminates the heavy motor components while maintaining the speaker's core function, enabling both weight reduction and flexibility.
Solution Approach 2:
The patent employs thin film structures including the electroactive polymer layer, flexible substrate, and thin protective layers. These flexible films replace rigid components, allowing the speaker to be bent and conform to curved surfaces while maintaining structural integrity and acoustic performance.
2Ease of manufacture
If a voice coil diaphragm speaker is used, then sound output is achieved, but transparency cannot be implemented
Solution Approach 1:
The patent uses thin transparent films for the electroactive polymer layer, flexible substrate, and protective layers. The thin film structure allows light to pass through, achieving transparency while maintaining the speaker's functional performance.
Solution Approach 2:
The patent employs transparent conductive materials and transparent electroactive polymer compositions to create a composite structure that is both transparent and functionally active. The composite materials maintain electrical conductivity and acoustic functionality while allowing light transmission.
3Adaptability or versatility
If a conventional speaker is coupled to the display panel, then sound function is added, but the thickness of the display panel is excessively increased
Solution Approach 1:
The patent merges the speaker structure with the display panel structure by integrating the electroactive polymer layer directly onto the flexible substrate, which is already part of the display panel assembly. This merging eliminates separate speaker components and reduces overall thickness.
Solution Approach 2:
The patent uses ultra-thin film structures with total thickness in the micrometer range, allowing the speaker to be integrated into the display panel without significantly increasing thickness. The thin films maintain structural integrity while minimizing added bulk.
4Ease of manufacture
If the electroactive layer has a flat surface, then manufacturing is simple, but sound pressure level is insufficient
Solution Approach 1:
The patent introduces convex or concave curved structures on the surface of the electroactive polymer layer. These curved surfaces act as acoustic lenses or resonators that focus and amplify sound waves, significantly improving sound pressure level while maintaining compatibility with standard manufacturing techniques like molding or embossing.
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 film speaker achieves improved sound pressure levels, flexibility, and transparency, enabling its integration into flexible display devices with reduced thickness and enhanced sound reproduction capabilities.
Implementation Method 1
an electroactive layer having a first surface and a second surface opposite to the first surface
Implementation Method 2
a film speaker which is capable of being applied to a flexible display device and has an improved sound pressure level (SPL)
Data Source
AI summary
A vibration generating device includes an electroactive layer having a first surface and a second surface opposite to the first surface, and including an unevenness structure; and a first electrode and a second electrode on at least one of the first surface and the second surface of the electroactive layer, wherein one or more of the first electrode and the second electrode covers an entire surface of at least one or more of the first surface and the second surface of the electroactive layer including the unevenness structure.