Electrophoretic Fluid Color Tuning via Adsorbed Colorants
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Solution Overview
Problem
Existing electrophoretic display technologies face challenges in achieving specific color coordinates efficiently and cost-effectively, particularly in creating a wide range of colors, including difficult shades like neutral absorbing black and good green, due to the complexity and expense of dye design and synthesis, as well as issues with color leaching and contamination in non-polar media.
Innovation Solution
The development of an electrophoretic fluid comprising a solvent and multiple sets of particles with the same electric charge sign and similar electrophoretic mobilities, allowing these particles to behave as a single set in an electrical field, enabling efficient color tuning and mixing to achieve desired color coordinates without affecting charge or mobility, thereby simplifying the production of a broad color gamut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dye chromophores structure is changed or alternative pigment is found to obtain desired color coordinate, then color accuracy is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The invention segments the color generation function into two independent parts: (1) particles with standardized chromophores that provide base color, and (2) colorant molecules that provide fine-tuning capability. This segmentation allows independent optimization of particle synthesis and colorant formulation, reducing overall manufacturing complexity while maintaining color accuracy.
Solution Approach 2:
The invention introduces colorant molecules as intermediary substances between the particles and the desired final color. These colorants adsorb onto particle surfaces and act as a mediator that adjusts the optical properties without requiring modification of the particle core structure, thereby simplifying the manufacturing process.
2Adaptability or versatility
If dye blending is performed prior to particle synthesis to achieve desired color, then color variety is improved, but dye incorporation control becomes difficult and synthesis time increases
Solution Approach 1:
The invention performs preliminary action by pre-synthesizing particles with standardized chromophores and stable electrophoretic properties. This preliminary particle production can be done in bulk and stored, then later combined with different colorant molecules to create various colors, thereby decoupling particle synthesis from color formulation and improving overall productivity.
Solution Approach 2:
The invention changes the parameter of color formulation from 'dye structure' to 'colorant molecule selection'. By keeping particle parameters standardized and only varying the colorant molecules, the system achieves color variety without compromising synthesis efficiency or particle performance consistency.
3Adaptability or versatility
If multiple colored particles are used to expand color gamut, then color range is improved, but particle mobility uniformity deteriorates
Solution Approach 1:
The invention segments the color function from the particle core by using adsorbed colorant molecules rather than incorporating different dyes into different particle batches. This ensures all particles have identical electrophoretic properties while the color varies only through the surface-adsorbed colorants, maintaining mobility uniformity across the entire color gamut.
Solution Approach 2:
The invention maintains homogeneity in particle composition, size, charge, and electrophoretic mobility across all particles regardless of their final color. The only variable parameter is the type and concentration of adsorbed colorant molecules, which do not affect the fundamental electrophoretic behavior of the particles.
4Manufacturing precision
If complex dye synthesis programs are used to achieve specific colors, then color precision is improved, but production cost and time increase
Solution Approach 1:
The invention extracts the color-tuning function from the particle synthesis process itself and places it in a separate, simpler step involving colorant molecule adsorption. This extraction eliminates the need for complex, time-consuming dye synthesis programs while maintaining color precision through controlled adsorption of pre-selected colorant molecules.
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 allows for the creation of a wide range of colors, including challenging shades, with improved color consistency and reduced production costs, while maintaining stable electrophoretic properties, suitable for applications in electrophoretic displays such as electronic paper.
Implementation Method 1
An EPD generally comprises charged electrophoretic particles dispersed between two substrates, each comprising one or more electrodes. If a voltage is applied between the electrodes, charged particles move to the electrode of opposite polarity.
Data Source
AI summary
This invention relates to electrophoretic fluids, the use of these fluids for the preparation of an electrophoretic display device, and electrophoretic displays comprising such fluids.