Electrowetting Optical Device With Liquid Crystal Memory Effect
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Solution Overview
Problem
Existing electro wetting effect-based display devices lack a memory effect, requiring continuous power to maintain the state of fluid positioning, which is not suitable for low-power applications like electronic paper, and necessitate additional components like thin film transistors for dot matrix displays, complicating the structure.
Innovation Solution
An optical device with a configuration of two substrates, a partition, and electrodes, using a polar or conductive first fluid and a liquid-crystalline second fluid with added dichroic pigments and chiral material, allowing voltage-controlled fluid positioning with a memory effect due to the high viscosity and molecular orientation of liquid crystals, enabling state retention without continuous power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional electro wetting effect-based display device is used, then the device can control light transmission and reflection, but it requires continuous power to maintain the fluid state and lacks a memory effect
Solution Approach 1:
The patent changes the physical parameter of the second fluid from a conventional immiscible liquid to a liquid-crystalline material. This parameter change gives the fluid high viscosity and molecular orientation properties, enabling it to maintain its position and optical state without continuous power supply, thus achieving a memory effect while reducing power consumption.
Solution Approach 2:
The patent creates a composite system by combining two immiscible fluids with different properties: a polar/conductive first fluid and a liquid-crystalline second fluid containing dichroic pigments. This composite approach allows the device to leverage the electro-wetting properties of the first fluid while the liquid-crystalline second fluid provides the memory effect, resolving the contradiction between reliability and power consumption.
2Adaptability or versatility
If conventional electro wetting display technology is applied to dot matrix displays, then display functionality is achieved, but additional switching elements like thin film transistors are required, complicating the structure
Solution Approach 1:
The patent extracts and removes the need for additional switching elements like thin film transistors from the pixel structure. By endowing the second fluid with memory effect through its liquid-crystalline properties, the system can maintain its state without external switching components, thereby simplifying the device structure while retaining dot matrix display capability.
Solution Approach 2:
The liquid-crystalline second fluid serves itself by maintaining its positioned state and optical properties without requiring external control elements. The high viscosity and molecular orientation of the liquid crystal material enable the fluid to 'remember' its state autonomously, eliminating the need for additional switching elements and simplifying the overall device structure.
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 device achieves a memory effect in electro wetting-based optical devices, allowing for low-power operation and simplifying the structure by maintaining fluid states without continuous power, enabling efficient control of transmissivity, reflectance, and color, suitable for reflective and transmissive displays with reduced power consumption.
Implementation Method 1
Japanese Unexamined Patent Application Publication (Published Japanese Translation of PCT International Application) No. 2007-531917 discloses a display device based on an electro wetting effect
Implementation Method 2
The reason for this is considered to be a result of the relatively high viscosity of the liquid-crystalline material
Implementation Method 3
liquid crystal molecules are of an elongated molecular shape and have a tendency (molecular orientation) of the becoming aligned
Implementation Method 4
the second fluid preferably contains pigments (for instance, dichroic pigments)
Data Source
AI summary
To realize a memory effect in an optical device using the electro wetting effect. An optical device includes: first and second substrates placed opposite each other; a partition provided therebetween; a first electrode provided on one side of the first substrate, at least a part thereof overlapping with a region surrounded by the partition in a plan view; second and third electrodes provided on one side of the second substrate and which are respectively placed opposite the first electrode across the region surrounded by the partition; a smoothing layer provided on one side of the second substrate and which covers the second and third electrodes; and first and second fluid, which are incompatible, disposed in the region surrounded by the partition. The first fluid is made of a liquid body possessing polarity or conductivity, and the second fluid is made of a liquid body containing a liquid-crystalline material.