Coloured Polymer Particles for Electrophoretic Displays
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Solution Overview
Problem
Current electrophoretic display technologies lack a simple and cost-effective method for preparing bright, full-color particles suitable for electronic paper, requiring complex processes and specific applications, and are limited by the need for multiple steps and expensive drying processes.
Innovation Solution
A reverse emulsion solvent removal process is used to create charged, highly reflective colored or black polymer particles by incorporating inorganic pigments into organic polymers, allowing for easy dispersion in non-polar media and manipulation of particle properties like size and charge, without the need for complex cell structures or expensive drying steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If complex cell structures and drive schemes are used to achieve full color particles, then color display capability is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into a single particle system. Colored polymer particles are designed to simultaneously provide color display, electrophoretic mobility, and stability without requiring separate cell structures or drive schemes for each function. This integration eliminates the need for complex multi-component systems while achieving full-color capability.
Solution Approach 2:
The colored polymer particles are designed as universal components that can function in simple electrophoretic display cells. Each particle inherently provides color, charge for electrophoresis, and structural stability, making them adaptable to various display configurations without requiring specialized cell structures or complex drive schemes.
2Manufacturing precision
If expensive drying steps are used in particle preparation, then particle quality is improved, but manufacturing cost increases
Solution Approach 1:
The patent employs a disposable polymer matrix that encapsulates the pigment particles. This matrix is designed to be discarded along with the pigment during the electrophoretic switching process, eliminating the need for expensive drying steps to preserve pigment integrity. The polymer serves its purpose and is then replaced, simplifying the manufacturing process while maintaining particle quality.
Solution Approach 2:
The invention changes the physical and chemical parameters of the particle system by using a soluble polymer matrix that can be dissolved and replaced. This allows particles to be prepared in liquid form without expensive drying steps, and the polymer can be easily removed or replaced by dissolution, significantly reducing manufacturing costs while maintaining particle quality.
3Reliability
If multiple preparation steps are used to create colored particles, then particle performance is improved, but productivity decreases
Solution Approach 1:
The patent incorporates pigment particles into the polymer matrix during the polymerization process itself, rather than requiring subsequent encapsulation or coating steps. This preliminary incorporation of the pigment into the forming polymer structure eliminates multiple preparation steps while ensuring uniform distribution and optimal performance of the colored particles.
Solution Approach 2:
The invention combines pigment incorporation, particle formation, and polymer matrix creation into a single integrated process. By merging these previously separate steps into one simultaneous operation during polymerization, the method achieves high particle performance while dramatically improving preparation efficiency and productivity.
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
This process enables the production of colored polymer particles with excellent light fastness, heat stability, and electrophoretic mobility, facilitating the construction of full-color electrophoretic displays without additional color filters and reducing the risk of particle damage during processing.
Implementation Method 1
forming a reverse emulsion comprising at least one polymer, at least one coloured or black inorganic pigment, at least one polar solvent, at least one non-polar solvent, and at least one surfactant
Implementation Method 2
removing the polar solvent or polar solvents by evaporative methods
Implementation Method 3
EPDs (Electrophoretic Displays) can fulfil this requirement... charged particles move to the electrode of opposite polarity
Data Source
AI summary
This invention relates to colored polymer particles prepared by a reverse emulsion solvent removal process, electrophoretic fluids comprising such particles, and electrophoretic display devices comprising such fluids.