Colored Fluids for Electrowetting Devices
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Solution Overview
Problem
Conventional electrowetting devices face limitations due to the use of water and traditional colorants, such as dyes, which suffer from poor light and weather fastness, high cost, inadequate solubility, and stability issues, necessitating improved colored fluids for enhanced performance and durability.
Innovation Solution
Development of colored polar and non-polar fluids containing oligomeric and polymeric dyes and pigments, specifically designed for electrowetting, electrofluidic, and electrophoretic devices, with optimized solubility, conductivity, and stability to maintain desired functions over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If dyes are used as colorants in electrowetting devices, then vivid colors and low viscosity are achieved, but light fastness and weather fastness deteriorate
Solution Approach 1:
The patent uses composite colorant systems combining dyes and pigments in specific ratios. The dye component provides vivid color and low viscosity, while the pigment component adds light fastness and weather fastness. This composite approach allows the system to simultaneously achieve color intensity and durability that neither component could provide alone.
2Reliability
If pigments are used as colorants in electrowetting devices, then light fastness and resistance to solvents are improved, but transparency and solubility deteriorate
Solution Approach 1:
The patent formulates composite colorant systems where pigments are combined with dyes and surfactants. The pigment provides light fastness while the dye and surfactant components ensure adequate solubility and transparency. This composite formulation allows the system to achieve both durability and optical properties that would be compromised by using pigments alone.
3Ease of manufacture
If water is used as solvent in electrowetting devices, then cost is reduced, but temperature stability deteriorates due to expansion and freezing
Solution Approach 1:
The patent modifies the solvent composition by replacing pure water with water-miscible organic solvents such as alcohols, esters, or ketones. This parameter change in the solvent system raises the freezing point and eliminates expansion issues while maintaining compatibility with the colorant system. The modified solvent composition provides temperature stability without completely sacrificing the cost advantages of aqueous-based systems.
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 new colored fluids provide improved durability, higher chroma, and contrast ratios, along with fast switching speeds and low power consumption, while minimizing impact on device components.
Implementation Method 1
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
Implementation Method 2
electrophoretic devices
Implementation Method 3
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
Data Source
Figure 1A~2B
Figure 3A~3C
Figure 4A~4B
AI summary
Colored fluids for electrowetting, electrofluidic, and electrophoretic chromatophore devices are disclosed. In one embodiment, the colored fluid includes at least one solvent and at least one oligomeric and/or polymeric dye in the solvent. The oligomeric dye has at least one chromophore attached to one or more oligomeric chains, and the polymeric dye has at least one chromophore attached to one or more oligomeric and/or polymeric chains. The dye also has a molecular weight from 400 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. The solvent may be polar or non-polar each having specific properties defined.