Binder Layer Segmentation for Electrophoretic Display Strength
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Solution Overview
Problem
Existing electrophoretic display sheets face challenges in achieving high sheet strength, reliability, and display quality, particularly when using flexible substrates, due to issues like particle segregation, sedimentation, and pressure sensitivity, which affect the transparency and migration space of electrophoretic particles.
Innovation Solution
A manufacturing method involving the formation of partitions on a first substrate and a binder layer on a second substrate, where the binder layer is used to affix the partitions and substrate together, enhancing sheet strength and preventing particle movement, while allowing for flexible substrate use and efficient electrophoretic particle migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If partitions are formed on the first substrate and affixed using only peripheral sealant, then the device structure is simple and manufacturing is easy, but the sheet strength is insufficient and particle segregation occurs
Solution Approach 1:
The binder layer is divided into two functional regions: a first binder layer region that fills the gap between partitions and provides particle confinement, and a second binder layer region that affixes partitions to the second substrate. This segmentation allows each region to perform its specific function optimally while working together to solve the contradiction between manufacturing simplicity and sheet strength.
Solution Approach 2:
The binder layer acts as an intermediary substance between the partitions and the second substrate, providing both mechanical bonding (strength) and particle confinement (preventing segregation). This intermediary layer resolves the contradiction by enabling simple peripheral affixing while achieving strong sheet structure through the mediating binder material.
2Ease of operation
If a gap is secured between the partition and the second substrate, then the partition does not completely separate the electrophoretic dispersion liquid, but particle segregation and sedimentation are likely to occur
Solution Approach 1:
The binder layer exhibits local quality differences through its two regions: the first binder layer region fills gaps locally between partitions and the second substrate to prevent particle movement, while the second binder layer region provides overall affixing. This local differentiation resolves the contradiction by maintaining gap spaces where needed while filling critical gaps to prevent segregation.
3Adaptability or versatility
If the electrophoretic display sheet is bent during use, then flexibility is achieved, but partition deformation and liquid leakage occur
Solution Approach 1:
The binder layer functions as a composite material system with two distinct regions that work together: the first region provides flexible gap-filling that accommodates bending, while the second region provides strong affixing that maintains structural integrity. This composite approach resolves the contradiction between flexibility and structural integrity during bending operations.
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 method results in an electrophoretic display sheet with high reliability, flexibility, and improved display performance, even when bent, by securing the binder layer and partitions together, thus preventing particle segregation and leakage, and allowing for efficient manufacturing with reduced costs.
Implementation Method 1
The display layer is filled with a dispersion liquid in which, for example, white particles to be positively charged and black particles to be negatively charged are dispersed in a liquid phase dispersion medium. Such an electrophoretic display sheet is configured such that a voltage is applied between the pair of electrodes to cause the white particles and black particles to migrate in an intended direction
Data Source
AI summary
An electrophoretic display sheet manufactured by forming on one surface of a first substrate partitions with an opening and applying and forming a binder layer on one surface of a second substrate, and then causing an electrophoretic dispersion liquid containing black particles and white particles dispersed in a dispersion medium to permeate into the binder layer and affixing the first substrate and the second substrate in a direction in which the surface of the binder layer with the electrophoretic dispersion liquid permeated therein and the surface of the partitions are opposite each other, and a method of manufacturing the electrophoretic display sheet are provided.