Colour Electrochromic Display Layering for Hidden Message Effects

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Solution Overview

Problem

Existing electrochromic fixed image displays face challenges in achieving a visually appealing 'hidden message effect' in the off-state, where the message is not apparent, and the color matching of symbol defining layers and electrolyte layers is laborious and can negatively affect display performance.

Innovation Solution

The display incorporates a stack of layers including a color layer, a first electrode layer, a symbol defining layer, an electrolyte layer, and a counter electrode layer, where the symbol defining layer is electronically and ionically insulating with openings defining symbols, allowing for a 'hidden message effect' without extensive color matching, and enabling multiple colors across the display.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If color matching is performed between symbol defining layer and electrolyte layer to achieve hidden message effect, then visual appearance is improved, but manufacturing complexity and time increase

Engineering Contradiction:
Improvevisual appearanceVSAvoidmanufacturing time
Core Design Contradiction:
Illumination intensityVSLoss of time

Solution Approach 1:

The invention extracts the color matching requirement from the symbol defining layer and electrolyte layer by introducing a separate color layer. This color layer is specifically designed to match the electrolyte color, thereby hiding the message in the off-state without requiring the symbol defining layer to match the electrolyte color. This separation eliminates the time-consuming color matching process while maintaining the hidden message effect.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The color layer acts as an intermediary element between the symbol defining layer and the electrolyte layer. It serves as a visual mask that matches the electrolyte color in the off-state, preventing the symbol defining layer from needing to match the electrolyte color directly. This intermediary approach simplifies manufacturing by decoupling the color matching requirement from the structural layers.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If color matching is performed between symbol defining layer and electrolyte layer to achieve hidden message effect, then visual appearance is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvevisual appearanceVSAvoidmanufacturing complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The invention extracts the color matching function from the symbol defining layer and electrolyte layer by introducing a dedicated color layer. This color layer specifically matches the electrolyte color to create the hidden message effect, while the symbol defining layer focuses solely on defining the symbol geometry. This functional separation reduces manufacturing complexity by eliminating the need for precise color matching between multiple layers.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention segments the color matching function into a separate color layer, distinct from the symbol defining layer and electrolyte layer. This segmentation allows each layer to have a specific function: the color layer handles color matching with the electrolyte, the symbol defining layer handles symbol geometry, and the electrolyte layer handles electrochemical function. This modular approach simplifies the overall manufacturing process.

Inventive Principle:
Principle #1Segmentation

3Illumination intensity

If color matching is performed between symbol defining layer and electrolyte layer to achieve hidden message effect, then visual appearance is improved, but display performance deteriorates due to negative effects of colored pigments

Engineering Contradiction:
Improvevisual appearanceVSAvoiddisplay performance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The invention extracts the color matching requirement from the functional layers (symbol defining layer and electrolyte layer) and places it in a dedicated color layer. This allows the electrolyte layer to use optimal electrolyte materials without colored pigments that would degrade display performance, while the color layer provides the necessary visual masking function using pigments that do not interfere with electrochemical performance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The color layer serves as an intermediary that provides the color matching function without compromising the electrochemical performance of the electrolyte layer. By placing the color matching function in a separate layer, the invention avoids introducing colored pigments into the electrolyte, which would otherwise have negative effects on display reliability and performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 provides a visually appealing 'hidden message effect' with improved color contrast and sharpness, facilitating efficient, low-cost manufacturing on flexible substrates, and allowing for multiple colors in different display portions.

Implementation Method 1

a first electrode layer comprising an electrically conducting electrochromic and electrochemically active organic polymer material which is electrochemically switchable between two different visually detectable colouring states

Methodology Applied
Scientific EffectElectrochromism: Electrochromism

Implementation Method 2

an electrochromic layer (EC-layer) and a counter electrode, wherein the display is arranged to change colour upon reduction of said electrochromic layer

Methodology Applied
Scientific EffectRedox reactions: Redox Reactions

Data Source

PatentEP4260138B1Colour electrochromic display
Publication Date: 2025.07.30 RISE RES INST OF SWEDEN AB
  • EP4260138B1 patent drawingFigure 1a~1b
  • EP4260138B1 patent drawingFigure 1c
  • EP4260138B1 patent drawingFigure 2a~4b

AI summary

There is provided an electrochromic fixed image display and a method for manufacturing the display. The electrochromic fixed image display for displaying a predetermined symbol comprising a stack of layers of: a colour layer which is configured to provide a resulting colour contrast to the display when comparing its on-state and off-state; a first electrochromic electrode layer arranged behind said colour layer in a viewing direction; an electronically and ionically insulating symbol defining layer, arranged behind the first electrode layer, which comprises at least one opening defining the shape the predetermined symbol; an electrolyte, arranged behind the symbol defining layer, which fills and covers the opening of said symbol defining layer; and a counter electrode layer, arranged behind the electrolyte layer, comprising an electronically conductive material, wherein the electrolyte layer is in ionic contact with the first electrode layer and the counter electrode layer.