Electrochromic Display Charge Retention Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrochromic display elements face challenges in achieving high white reflectance and contrast ratio while maintaining multicolor display capabilities, often resulting in low visibility due to color filter absorption and image blurring issues, and are prone to electrode erosion.
Innovation Solution
An electrochromic display element with a charge retention layer formed from a mixed film of polymer and conductive microparticles, combined with an electrolyte layer and multiple electrochromic layers, which enhances color development and dissipation efficiency, reduces voltage requirements, and improves durability by preventing charge diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If color filters are used to display multiple colors, then color display capability is improved, but white reflectance and contrast ratio are significantly lowered
Solution Approach 1:
The patent employs electrochromic compounds that can reversibly change color through redox reactions when voltage is applied. Different electrochromic compounds or layers are used to achieve different colors (e.g., blue, red, green), eliminating the need for traditional light-absorbing color filters while maintaining high white reflectance in the uncolored state.
Solution Approach 2:
The patent uses composite structures combining multiple electrochromic layers with different compounds (e.g., viologen for blue, phenothiazine for red, spirooxazine for green) to achieve multicolor display. This composite approach allows each layer to contribute its color-changing property without the light absorption penalties of conventional color filters.
2Adaptability or versatility
If each pixel is divided into three color parts (R, G, B) with color filters, then color display is improved, but reflectance is significantly lowered
Solution Approach 1:
The patent changes the fundamental mechanism from passive color filtering to active color generation through electrochemical reactions. By controlling the oxidation state of electrochromic compounds via applied voltage, the display can dynamically generate colors without absorbing ambient light, thereby maintaining high reflectance while achieving full-color display capability.
3Speed
If low resistance films with high conductivity are used, then switching speed is improved, but electrode erosion increases
Solution Approach 1:
The patent employs porous insulating films with controlled pore structures that allow efficient ion transport while providing physical protection to the electrode interfaces. The porous structure increases surface area for electrochemical reactions, enabling fast switching without requiring high electrode conductivity that would lead to erosion.
Solution Approach 2:
The patent introduces insulating films as intermediary layers between conductive electrodes and electrolyte solutions. These films act as protective barriers that prevent direct contact and erosion of electrodes while maintaining ionic conductivity through their porous structures, thus decoupling the conflicting requirements of speed and durability.
4Manufacturing precision
If charge retention layer is formed to prevent charge diffusion, then image definition is improved, but manufacturing complexity increases
Solution Approach 1:
The patent designs porous insulating films that simultaneously serve multiple functions: preventing charge diffusion to maintain image definition, facilitating ion transport for electrochromic switching, and protecting electrode interfaces. This multi-functionality reduces the need for separate dedicated layers, thereby limiting the increase in manufacturing complexity despite improved image definition.
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 solution enables high-definition, multicolor display with improved durability and reduced manufacturing costs, maintaining excellent display quality and resolution without increasing manufacturing costs.
Implementation Method 1
Electrochromism is a phenomenon displayed by specific materials of reversibly changing optical properties when an amount of voltage is applied to the materials
Implementation Method 2
chemical compounds, which induce a reversible redox reaction to reversibly change their colors when a voltage is applied to the chemical compounds
Implementation Method 3
a charge retention layer formed of an insulating film having a porosity of 10% or more and a resistivity of 1.0E+05 ohm·cm or less
Implementation Method 4
an insulating film having a porosity of 10% or more and a resistivity of 1.0E+05 ohm·cm or less
Data Source
AI summary
A disclosed electrochromic display element includes a display substrate, a counter substrate facing the display substrate, display electrodes arranged between the display substrate and the counter substrate, electrochromic layers formed on the respective display electrodes, a plurality of drive elements arranged on the counter substrate at predetermined intervals, a plurality of pixel electrodes arranged on the drive elements, a charge retention layer formed over the pixel electrodes as a continuous layer, the charge retention layer being formed of a mixed film including a polymer and one of electric conductive microparticles and semiconductor microparticles, and an electrolyte layer sandwitched between the display substrate and the charge retention layer.