Colored Metalorganic Fluids for Electrowetting Displays
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Solution Overview
Problem
Existing electrowetting devices face challenges with solubility issues of colorants in metalorganic solvents, particularly silicone fluids, leading to poor color stability and performance due to low solubility of conventional dyes and pigments, which limits their application in electrowetting, electrofluidic, and electrophoretic devices.
Innovation Solution
Development of colored metalorganic fluids incorporating modified, oligomeric, or polymeric dyes with chromophores attached to low molecular weight groups or oligomeric/polymeric chains, which are soluble in silicon or germanium-based solvents, along with optional pigments, to enhance coloration and stability, while maintaining suitable conductivity and viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dyes and pigments are used in metalorganic solvents, then the device structure is simple and easy to manufacture, but the solubility is very low leading to poor color stability and performance
Solution Approach 1:
The patent modifies the chemical structure of dyes and pigments by changing parameters such as adding metal complexes (phthalocyanine, porphyrin, corrin rings with Si, Ge, Sn, Pb), oligomeric or polymeric chains, or specific functional groups (carboxylic acid, sulfonic acid, hydroxyl, amino) to improve solubility in metalorganic solvents while maintaining color stability
Solution Approach 2:
The patent creates composite colorant systems by combining dyes with metalorganic compounds, using mixed ligand complexes where the colorant molecule is coordinated to metal centers within the metalorganic framework, achieving both solubility and stability
2Adaptability or versatility
If water-based solvents are used in electrowetting devices, then the device can be manufactured easily, but the physical properties of water such as expansion at higher temperature and freezing point limit the applications
Solution Approach 1:
The patent transitions from water-based to metalorganic solvent systems (silicones, organosilicones, cyclic siloxanes) by changing the fundamental chemical parameters of the solvent, enabling operation across extreme temperature ranges from -50°C to +200°C without freezing or expansion issues
Solution Approach 2:
The patent uses metalorganic solvents that create an inert chemical environment, resistant to oxidation and degradation, allowing the electrowetting device to operate reliably in diverse temperature and humidity conditions without solvent degradation
3Stability of the object's composition
If silicone fluids are used as solvents, then the device achieves low viscosity and surface tension with wide temperature range, but the compatibility with colorants is very poor
Solution Approach 1:
The patent modifies dye structures by introducing silicon-containing oligomeric or polymeric chains, or metal complexes with coordination chemistry that matches the silicone fluid environment, transforming the chemical parameters of the colorant to achieve compatibility with non-polar silicone solvents
Solution Approach 2:
The patent uses metalorganic compounds as intermediary structures that bridge the colorant and silicone fluid, where the metal center coordinates with the colorant ligands while the organic ligands provide compatibility with the silicone solvent environment
4Speed
If the oil film is disrupted by electrowetting, then the switching speed is fast, but the color is lost during the switching process
Solution Approach 1:
The patent uses dynamically responsive colorants that can change their optical properties in response to the electric field, maintaining color visibility during the switching transition by adapting to the changing oil film configuration rather than requiring a static color state
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 use of these colored metalorganic fluids improves durability, chroma, and contrast ratios, enabling fast switching speeds and low power consumption, with enhanced device performance and stability over time.
Implementation Method 1
The term 'electrowetting' describes the effects of an electric field on the contact angle of a liquid with a hydrophobic surface. With an electric field, the liquid distributes over, or wets, a surface that initially repels the liquid resulting in a change in the spectral properties of a device.
Implementation Method 2
Interfacial tension between two immiscible fluids can be controlled by electrical potential. This basic principle is used in a diverse and continuously growing group of electro-optical modulated displays that include devices in which the optical state of an imaging material is modulated or changed by subjecting the imaging material to an electric field
Data Source
AI summary
Colored metalorganic fluids for electrowetting, electrofluidic, and electrophoretic devices are disclosed. The colored fluid can include a polar or nonpolar solvent including silicon and/or germanium and a modified, oligomeric, or polymeric dye. The dye includes a chromophore attached to a low molecular weight group with molecular weight 10 to 800 or an oligomeric or polymeric chain, which includes silicon and/or germanium. The dye has a molecular weight from 100 to 100,000, solubility in the solvent of at least 5% wt at 25° C., and a dynamic viscosity from 0.5 cPs to 2,000 cPs at 25° C. If the solvent is polar, the fluid has a conductivity from about 0.01 pS/cm to 3000 pS/cm, a surface tension of 15 dynes/cm to 90 dynes/cm at 25° C., and a total content of monatomic ions with radii smaller than 2.0 A and polyatomic ions with radii smaller than 1.45 A less than 500 ppm.