Piezoelectric Polymer Composite Haptic Layer for Transparent Touch Feedback
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Solution Overview
Problem
Existing touch-sensitive devices face challenges in providing immediate and minute feedback due to the limitations of vibration motors like ERM and LRA, which require large mass, difficulty in frequency modulation, slow response speed, and opacity, while alternative materials like SMA and piezoelectric ceramics suffer from slow response, low durability, and opacity issues.
Innovation Solution
A touch-sensitive device utilizing an electroactive matrix formed by bonding piezoelectric ceramics and electroactive polymers with a hydrogen bond, enhancing transparency, ease of thinness, and piezoelectric properties, and using KNN-based piezoelectric ceramics for improved durability and environmental safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If vibration motors (ERM or LRA) are used for haptic feedback, then vibration intensity can be increased, but the device size increases and response speed decreases
Solution Approach 1:
The patent replaces traditional mechanical vibration motors (ERM/LRA) with a piezoelectric-based haptic device that uses electro-mechanical conversion. The piezoelectric material converts electrical signals directly into mechanical vibrations, eliminating the need for rotating masses and complex mechanical structures, thereby achieving faster response speed while maintaining vibration intensity.
Solution Approach 2:
The patent changes the fundamental operating parameters by using piezoelectric materials that respond to electrical fields rather than mechanical rotation. This allows for rapid frequency modulation and control of vibration characteristics through electrical signals, improving response speed compared to mechanical vibration motors.
2Power
If piezoelectric ceramics are used for haptic feedback, then piezoelectric property is high, but durability against external impact is low and the material is opaque
Solution Approach 1:
The patent employs composite material structures that combine piezoelectric ceramics with flexible substrates or polymer matrices. This composite approach maintains the high piezoelectric property of the ceramic while the surrounding flexible material provides mechanical protection against impact, improving durability without sacrificing electrical performance.
Solution Approach 2:
The patent uses flexible thin film structures to encapsulate or support the piezoelectric ceramic elements. These flexible films act as protective layers that absorb external impacts and prevent direct stress on the brittle ceramic, thereby improving reliability while maintaining the transparency and thinness required for display integration.
3Illumination intensity
If electroactive polymer is used for haptic feedback, then transparency and ease of thinness are improved, but piezoelectric property is insufficient and high driving voltage is required
Solution Approach 1:
The patent creates composite structures where electroactive polymers are combined with piezoelectric ceramic particles or layers. The polymer matrix provides transparency and flexibility, while the embedded piezoelectric ceramic phases provide the necessary piezoelectric property, achieving a balance between optical properties and electrical performance.
Solution Approach 2:
The patent applies local quality enhancement by concentrating piezoelectric ceramic materials in specific regions or interfaces within the electroactive polymer structure. This allows the bulk material to remain transparent and flexible while localized piezoelectric regions provide the required electrical-to-mechanical conversion capability.
4Ease of operation
If shape memory alloy is used for haptic feedback, then haptic feedback can be provided, but response speed is slow and the material is opaque
Solution Approach 1:
The patent replaces shape memory alloy's thermal-mechanical actuation mechanism with piezoelectric electro-mechanical conversion. This substitution eliminates the slow thermal response of SMA by using direct electrical-to-mechanical conversion in piezoelectric materials, achieving faster response speeds while maintaining haptic feedback functionality.
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 solution improves light transmittance and vibration intensity, reduces manufacturing complexities, and provides a safer, more environmentally friendly option with enhanced piezoelectric performance and flexibility, suitable for flexible display devices.
Implementation Method 1
an electroactive layer formed of an electroactive matrix in which a piezoelectric ceramic and an electroactive polymer (EAP) are bonded
Implementation Method 2
an electroactive layer formed of an electroactive matrix in which a piezoelectric ceramic and an electroactive polymer (EAP) are bonded
Data Source
AI summary
Provided is a touch sensitive device including an electroactive layer formed of an electroactive matrix, wherein the electroactive matrix has a structure in which a piezoelectric ceramic and an electroactive polymer (EAP) are bonded and an electrode disposed on at least one surface of the electroactive layer. According to an exemplary embodiment of the present disclosure, the touch sensitive device uses an electroactive matrix has an excellent transparency, can be made thin, and has a high piezoelectric property so that the light transmittance and the vibration intensity of the touch sensitive device can be improved.