Tin Oxide Electrochromic Display Layers for Crack-Resistant Bending
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Solution Overview
Problem
Existing electrochromic display elements using tin oxide particles with an average primary particle diameter less than 30 nm suffer from cracking when bent, leading to reduced transparency and responsiveness.
Innovation Solution
The use of tin oxide with an average primary particle diameter of less than 30 nm and a specific range of electrochromic compound mole amount per area, combined with a method to wash off unadsorbed compounds, results in an electrochromic display element with enhanced transparency and responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If tin oxide particles with average primary particle diameter less than 30 nm are used in the electrochromic layer, then transparency is improved, but the layer becomes prone to cracking when bent
Solution Approach 1:
The patent changes the particle size parameter of tin oxide to less than 30 nm to improve transparency while maintaining flexibility. This parameter optimization allows the electrochromic layer to achieve high transparency without cracking when bent, resolving the contradiction between transparency and cracking resistance
Solution Approach 2:
The patent creates a composite electrochromic layer combining tin oxide particles with electrochromic compounds. This composite structure leverages the transparency benefits of fine tin oxide particles while the electrochromic compound matrix provides structural integrity and crack prevention, solving the reliability issue
2Illumination intensity
If the amount of electrochromic compound is increased to enhance display quality, then color development is improved, but the layer becomes more prone to cracking
Solution Approach 1:
The patent optimizes the concentration parameter of electrochromic compound within the specific range of 2.0×10−8 mol/cm2 through 2.0×10−7 mol/cm2. This precise parameter control ensures sufficient color development for high display quality while preventing excessive compound accumulation that would cause cracking
Solution Approach 2:
The patent applies partial action by using a moderate amount of electrochromic compound rather than maximizing it. This controlled quantity provides adequate display quality while avoiding the harmful effect of excessive compound that leads to cracking, thus resolving the contradiction
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 prevents cracking in the electrochromic layer, maintaining high transparency and responsiveness during bending, ensuring a stable and effective display performance.
Implementation Method 1
Electrochromism is a phenomenon that an oxidation reduction reaction occurs reversibly and color changes occur reversibly in response to application of a voltage
Implementation Method 2
titanium oxide has a hydroxyl group (OH group) that facilitates supporting the electrochromic compound by adsorption
Data Source
AI summary
Provided is an electrochromic display element including a first substrate, a first electrode over the first substrate, a first electrochromic layer over the first electrode, an electrolyte layer over the first electrochromic layer, a second electrode over the electrolyte layer, and a second substrate over the second electrode. The first electrochromic layer contains tin oxide having an average primary particle diameter of less than 30 nm and an electrochromic compound containing a functional group bindable to the tin oxide. The amount by mole of the electrochromic compound per area of the first electrochromic layer is from 2.0×10−8 mol/cm2 through 2.0×10−7 mol/cm2.