Electrochromic Element Gel Layer Design for Color Separation
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Solution Overview
Problem
Electrochromic elements (EC elements) face vertical color separation issues due to segregation of anodic and cathodic EC compounds, leading to color inhomogeneity, which is not effectively addressed by increasing viscosity alone as it also slows down the response speed.
Innovation Solution
The EC element design includes an effective optical region within a transmittance variable region, where the shortest distance from the periphery of the effective optical region to the transmittance variable region is between 7.5% and 25% of the region's length, and an average color inhomogeneity index is 0.01 or less, to minimize vertical color separation while maintaining responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the viscosity of the solution containing EC compounds is increased to suppress vertical color separation, then color inhomogeneity is reduced, but the response speed of the EC element decreases
Solution Approach 1:
The patent changes the physical state of the EC layer from a solution to a gel by incorporating a gelator substance. This parameter change allows the EC layer to maintain structural integrity and suppress vertical color separation while preserving ion mobility and response speed, resolving the contradiction between color uniformity and responsiveness.
Solution Approach 2:
The patent creates a composite EC layer by combining EC compounds with a gelator substance to form a gel. This composite structure provides both the color-changing functionality of the EC compounds and the structural stability of the gel, enabling suppressed vertical color separation without sacrificing response speed.
2Manufacturing precision
If a thickener is used to increase viscosity and suppress vertical color separation, then color inhomogeneity is reduced, but the movement of EC compounds during coloring is also suppressed
Solution Approach 1:
The patent transitions from using a thickener to use a gelator substance that forms a gel network. This parameter change allows the EC layer to maintain structural integrity during standing while permitting ion mobility during electrical coloring, thus suppressing vertical color separation without impeding coloring response.
Solution Approach 2:
The gelator substance acts as an intermediary that forms a gel network to constrain the EC compounds vertically while allowing horizontal ion transport during coloring. This intermediary structure resolves the conflict between preventing vertical separation and enabling coloring operation.
3Productivity
If the EC element is driven at high coloring density for long periods, then transmittance control is improved, but vertical color separation occurs more significantly
Solution Approach 1:
The gel composite structure provides a stable matrix that maintains EC compound distribution even under high coloring density conditions. The gel network prevents aggregation and vertical migration of EC compounds, allowing prolonged high-density operation without significant vertical color separation.
Solution Approach 2:
Instead of trying to prevent vertical color separation by restricting ion movement (which would slow coloring), the gel structure inverts the approach by providing a stable framework that naturally constrains vertical migration while maintaining horizontal ion transport, enabling high-density operation without color inhomogeneity.
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
This design effectively reduces vertical color separation, maintaining the responsiveness of the EC element and ensuring high-resolution displays and transmittance variable windows with minimal color inhomogeneity.
Implementation Method 1
Compounds for which the optical characteristics (the absorption wavelengths, the absorbances and the like) of the substances change by electrochemical oxidation-reduction reactions are called electrochromic (EC) compounds.
Implementation Method 2
the optical characteristics (the absorption wavelengths, the absorbances and the like) of the substances change by electrochemical oxidation-reduction reactions
Data Source
AI summary
The present disclosure includes an effective optical region within a transmittance variable region, and sets the transmittance variable region and the effective optical region so that a shortest distances from a periphery of the transmittance variable region to a periphery of the effective optical region, d1 and d2, are 7.5% or more and 25% or less of a length of the transmittance variable region on a straight line including the shortest distances, L1, in a vertical direction.