Charged Particle Coating for Electrophoretic Display Power Reduction
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Solution Overview
Problem
Existing electrophoretic display devices require a relatively large electric field to move electrophoretic particles effectively due to insufficient electric charge and sensitivity, leading to high power consumption.
Innovation Solution
A method of manufacturing charged particles by forming a coating layer on a mother particle using living polymerization, which allows control of electric charge and sensitivity by coupling a first chemical compound to the particle's surface and polymerizing a second chemical compound with ionic or functional groups, optionally incorporating chromophores for coloration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If organic or inorganic particles with charge control agents are used as electrophoretic particles, then the device structure is simple, but the electric charge on particles is insufficient and sensitivity to electric field is low
Solution Approach 1:
The patent uses composite particles consisting of a core particle (organic or inorganic) coated with a polymer layer containing ionic groups. This composite structure combines the simplicity of using standard particles with the enhanced charge properties of the polymer coating, resolving the contradiction between simple device structure and sufficient electric charge/sensitivity.
Solution Approach 2:
The patent changes the chemical parameters of the particle surface by coating with polymers having specific ionic groups (carboxyl, sulfonate, phosphate, amino, or quaternary ammonium groups). This parameter change increases the electric charge density and sensitivity without fundamentally altering the device structure.
2Reliability
If particles with sufficient electric charge are obtained, then sensitivity to electric field improves, but a relatively large electric field is required which results in large power consumption
Solution Approach 1:
The patent changes the charge density parameter by coating particles with polymers containing multiple ionic groups per particle. This increases sensitivity so that smaller electric fields can effectively move particles, reducing power consumption while maintaining sufficient sensitivity.
Solution Approach 2:
The patent creates copies of charge functionality by incorporating multiple ionic groups in the polymer coating, effectively multiplying the charge capacity of each particle without requiring proportionally larger electric fields, thus improving efficiency.
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 enables precise control of electric charge and sensitivity of the charged particles, reducing the power required to move them in an electric field, thus lowering power consumption and improving the reliability of electrophoretic devices.
Implementation Method 1
coupling a first chemical compound having at least a part where is going to be a starting point of living polymerization to the surface of the mother particle
Implementation Method 2
polymerizing a second chemical compound having an ionic group or a functional group convertible to an ionic group so as to form a polymer through the living polymerization that starts from the starting point of the first chemical compound
Implementation Method 3
particles move (migrate) in fluid by coulomb force when an electric filed is applied to a dispersion system in which the particles are dispersed in the fluid, and this phenomenon is called electrophoresis
Implementation Method 4
polymerizing a second chemical compound having an ionic group or a functional group convertible to an ionic group
Data Source
AI summary
A method of manufacturing a charged particle, comprising:a) providing a mother particle; and b) forming a coating layer that covers at least a part of a surface of the mother particle, wherein the step b) includes: coupling a first chemical compound having at least a part where is going to be a starting point of living polymerization to the surface of the mother particle; and polymerizing a second chemical compound having an ionic group or a functional group convertible to an ionic group so as to form a polymer through the living polymerization that starts from the starting point of the first chemical compound.