Electrophoretic Dispersion Solution Bistability
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Solution Overview
Problem
Existing electrophoretic dispersion solutions face challenges in achieving bistability, which is essential for stable electrophoretic mobility and static states, due to increased viscosity leading to delayed operations and higher driving voltages, while also struggling to maintain independent electrophoretic states of different particles in nonpolar solvents.
Innovation Solution
The use of a nonpolar solvent-based electrophoretic dispersion solution where electrophoretic particles are modified with copolymers containing monomers with charged groups and siloxane structures, allowing for controlled surface interactions and polymerization to enhance bistability and stability, thereby facilitating stable electrophoretic mobility and static states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a polymer is dissolved in a dispersion medium to enhance bistability, then bistability is improved, but viscosity of the dispersion medium is increased leading to decreased electrophoretic mobility
Solution Approach 1:
The patent changes the chemical composition parameters of the dispersion medium by using a nonpolar solvent with specific viscosity characteristics and incorporating polymers with controlled molecular weights (400,000-1,200,000) to achieve bistability while managing viscosity effects on electrophoretic mobility
Solution Approach 2:
The patent creates a composite dispersion medium system combining nonpolar solvents with specific polymers (polyisobutylene or polyalphaolefin) and electrophoretic particles, where the composite structure achieves both bistability and acceptable electrophoretic mobility through synergistic interactions
2Stability of the object's composition
If polyisobutylene with high molecular weight is used to enhance bistability through depletion effect, then aggregation is realized and bistability is enhanced, but operation speed decreases due to increased viscosity
Solution Approach 1:
The patent optimizes the molecular weight parameter of polyisobutylene within the range of 400,000-1,200,000 to achieve sufficient aggregation and bistability while minimizing the viscosity increase that would slow down electrophoretic particle movement
Solution Approach 2:
The patent uses polyalphaolefin as an alternative polymer with similar molecular weight range and depletion effect characteristics to polyisobutylene, providing a substitute solution that maintains bistability without excessive viscosity penalties
3Stability of the object's composition
If electrophoretic particles are used in nonpolar solvent, then bistability can be achieved, but it becomes difficult to maintain independent electrophoretic states of different particles
Solution Approach 1:
The patent applies different surface modifications to different electrophoretic particles, where at least one kind of particle has a copolymer with charged group-containing monomers while another kind has a polymer with specific monomers, creating local surface property differences that enable independent electrophoretic states
Solution Approach 2:
The patent modifies surface charge parameters and polymer composition parameters of different particle types to ensure they respond independently to applied voltages in the nonpolar solvent environment, maintaining bistability while achieving particle differentiation
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 approach enables stable electrophoretic mobility and static states, allowing for efficient image display with superior memory and reduced power consumption, while maintaining independent electrophoretic states of different particles, thus overcoming the limitations of previous solutions.
Implementation Method 1
a copolymer including subunits obtained by polymerization of a first monomer that has a charged group and a second monomer
Implementation Method 2
the electrophoretic particles are attracted to the transparent electrode to which the voltage is applied... the electrophoretic particles move toward transparent electrode opposite to the one to which the same potential is applied
Implementation Method 3
a copolymer including subunits obtained by polymerization of a first monomer that has a charged group... At least another kind of the electrophoretic particles include, on surfaces, a polymer including a subunit obtained by polymerization of a third monomer
Data Source
Figure 1~2
AI summary
An electrophoretic dispersion solution includes a nonpolar solvent and plural kinds of electrophoretic particles. At least one kind of the electrophoretic particles has, on surfaces, a copolymer including a first monomer that has a charged group and a second monomer expressed by a first formula represented as denotes a hydrogen atom or a methyl group, R' denotes a hydrogen atom or an alkyl group with a carbon number of 1 through 4, n is a natural number, and x denotes an integer of 1 through 3. At least another kind of the electrophoretic particles include, on surfaces, a polymer including a third monomer expressed by a second formula represented as as a component of the polymer. R denotes a hydrogen atom or a methyl group and R'' denotes an alkyl group with a carbon number of 4 or larger.