Electro-active polymer layer for phase retardation in touch displays
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Solution Overview
Problem
Existing display devices face challenges in reducing weight and thickness while minimizing external light reflectivity and manufacturing costs, particularly in portable devices where strong electric fields from electro-active polymers can interfere with other components and reduce visibility due to light reflection.
Innovation Solution
A display device incorporating a contact-sensitive device with an electro-active layer made of polyvinylidene fluoride (PVDF)-based polymers, uniaxially elongated to retard incident light phase by λ/4, and disposed between a display panel and a linear polarizer, which also functions as a shielding layer to minimize touch signal interference and external light reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If additional phase retardation films are added to reduce external light reflection, then visibility is improved, but weight and thickness increase
Solution Approach 1:
The electro-active layer is designed to perform multiple functions simultaneously: it provides phase retardation to reduce external light reflection, maintains flexibility for haptic feedback, and enables tactile sensing. By making the electro-active layer multi-functional, the patent eliminates the need for separate phase retardation films, thereby reducing overall weight while maintaining visibility performance
Solution Approach 2:
The patent combines the phase retardation function with the electro-active layer itself, merging two previously separate functions (haptic feedback and optical performance) into a single component. This integration allows the electro-active layer to serve both as the actuator for tactile feedback and as the phase retardation element, reducing the number of additional films needed
2Illumination intensity
If additional phase retardation films are added to reduce external light reflection, then visibility is improved, but manufacturing cost increases
Solution Approach 1:
The electro-active layer is engineered to provide multiple functions including phase retardation, flexibility, and tactile feedback capability. By making this single layer multi-functional, the patent eliminates the need for separate phase retardation films, thereby reducing material costs, assembly complexity, and manufacturing steps while maintaining visibility performance
Solution Approach 2:
The patent merges the phase retardation function into the electro-active layer itself, combining what were previously separate components (haptic actuator and optical element) into one integrated layer. This reduction in component count directly lowers manufacturing costs by reducing material expenses, assembly operations, and quality control steps
3Force
If strong electric field is applied to electro-active layer for haptic feedback, then tactile feedback is provided, but interference with other components occurs
Solution Approach 1:
The patent introduces a shielding layer positioned between the electro-active layer and other sensitive components. This intermediary layer blocks or attenuates the strong electric field generated during haptic feedback operations, preventing interference with touch sensors and other electronic components while allowing the electro-active layer to function effectively
Solution Approach 2:
The patent divides the display structure into functionally separated layers: the electro-active layer for haptic feedback, a shielding layer for electromagnetic protection, and a touch sensor layer for input detection. This segmentation allows each layer to perform its specific function without interfering with others, enabling strong electric fields in the electro-active layer without compromising touch sensor operation
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 achieves a thin profile, low external light reflectivity, and cost reduction by omitting additional phase retardation films, while providing effective tactile feedback and improved visibility in outdoor environments.
Implementation Method 1
the electro-active layer may be configured to retard a phase of incident light by about λ/4
Implementation Method 2
contact sensitive devices implemented in a film form by using electro-active polymers (EAPs)
Implementation Method 3
a linear polarizer on the contact sensitive device
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
Provided is a display device (100). The display device includes a display panel (110), a contact sensitive device (120) on the display panel, and a linear polarizer (130) on the contact sensitive device. The contact sensitive device (120) includes an electro-active layer (122) which may be uniaxially elongated and configured to retard a phase of incident light. Since the display device (100) includes the contact sensitive device (120) having the electro-active layer (122) configured to retard the phase of the incident light, a separate phase retardation film for suppressing external light reflection may be omitted. As a result, the thickness of the display device (100) may be decreased and manufacturing cost of the display device (100) may be reduced.