Patterned Piezo-Electrophoretic Displays for Thin, High-Contrast Imaging
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Solution Overview
Problem
Conventional piezo-electrophoretic displays are thick, bulky, and suffer from visual artifacts like blurriness and crosstalk due to charge spilling, making them unsuitable for thin, durable applications requiring high contrast ratios.
Innovation Solution
A method of creating piezo-electrophoretic displays with patterned piezoelectric layers interspersed with insulating materials or voids, and using conductive materials to form electrodes, which enhances contrast ratio and sharpness without increasing thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a thick layer of piezoelectric material is used to generate sufficient voltage for pigment particle movement, then the voltage magnitude is sufficient to achieve acceptable contrast ratio, but the display becomes too thick for thin, low-profile applications
Solution Approach 1:
The piezoelectric layer is segmented into multiple discrete piezoelectric elements arranged in an array, where each element corresponds to a pixel region. This segmentation allows the use of thinner individual piezoelectric layers while collectively providing sufficient voltage generation capability across the display area.
Solution Approach 2:
Different regions of the display have piezoelectric elements with locally optimized properties. The piezoelectric elements are positioned and dimensioned to provide appropriate voltage generation for their specific pixel regions, allowing thin overall display thickness while maintaining sufficient local voltage magnitude for contrast ratio.
2Power
If continuous layers of piezoelectric material are used to generate charge, then charge generation is sufficient, but charge spills into adjacent areas causing visual artifacts like blurriness and crosstalk
Solution Approach 1:
The piezoelectric layer is divided into discrete piezoelectric elements separated by insulating material regions. This segmentation confines the charge generation to specific pixel areas, preventing charge spilling into adjacent regions and eliminating visual artifacts like blurriness and crosstalk while maintaining sufficient charge generation for image display.
Solution Approach 2:
Insulating material regions are introduced between piezoelectric elements to extract or remove the harmful charge spilling effect. These insulating barriers prevent electrical charge from spreading laterally, thereby maintaining sharp image edges and preventing crosstalk between adjacent pixel regions.
3Power
If conventional piezo-electrophoretic displays are constructed with continuous piezoelectric layers, then charge generation is sufficient, but the displays are bulky and not durable for thin applications
Solution Approach 1:
The continuous piezoelectric layer is replaced with an array of discrete piezoelectric elements. This segmented structure reduces overall material usage and display thickness while improving flexibility and durability for thin applications. The discrete elements maintain sufficient charge generation capability through optimized arrangement and individual element properties.
Solution Approach 2:
The display employs thin piezoelectric elements and flexible substrate materials that enable the display to be bent and flexed without breaking. This flexible construction improves durability for thin, low-profile applications while maintaining the charge generation capability through the segmented piezoelectric element array.
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 results in thin, flexible displays with high contrast ratios and sharp edges, suitable for applications like security markers and bank notes, without the need for external power sources.
Implementation Method 1
a piezoelectric element which creates charge through physical motion or thermal expansion
Implementation Method 2
An electrophoretic display (END) is a non-emissive device based on the electrophoresis of charged pigment particles dispersed in a solvent or solvent mixture
Data Source
AI summary
Low voltage piezo-electrophoretic displays including low profile piezo-electrophoretic displays. In some embodiments, the piezoelectric material of the piezo-electrophoretic films can be selectively patterned with an insulating material during fabrication. In some embodiments, the piezoelectric material of the piezo-electrophoretic films can be selectively patterned with cuts, or partially-coated with a conductive material on a surface opposite to the electrode. Such films have high contrast ratio and are useful as security markers, authentication films, or sensors. The films are generally flexible. Some films are less than 100 μm in thickness. Some films are less than 50 μm in thickness. Displays formed from the films do not require an external power source.