Vertical Electrochromic Display Uncovered Rim
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Solution Overview
Problem
Directly addressed electrochromic displays face challenges in achieving sharp images and high manufacturing yield due to ion migration, leading to blurring of edges and increased switching voltage, which results in higher power consumption and potential electronic short-circuits.
Innovation Solution
A directly addressable display device with a stack of layers including an electrochemically active organic polymer material, a symbol defining layer, an electrolyte layer, and a counter electrode with a carbon layer, where the electrochromic layer has a smaller surface area than the opening in the symbol defining layer, creating an uncovered rim portion to prevent smearing and reduce switching voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the electrochromic layer has the same surface area as the opening in the symbol defining layer, then the colour change is complete across the entire opening area, but ion migration causes blurring of edges and reduces image sharpness
Solution Approach 1:
The electrochromic layer is designed with non-uniform spatial distribution: it covers the central area for complete colour switching while deliberately leaving the peripheral rim portion uncovered. This local differentiation allows the central region to achieve full colour change while the uncovered rim prevents ion migration-induced blurring, thus resolving the contradiction between colour switch completeness and image sharpness.
2Reliability
If a larger area of electrochromic material is used to ensure complete colour switching, then the colour change is more uniform, but the switching voltage increases leading to higher power consumption
Solution Approach 1:
The electrochromic layer is strategically positioned to cover only the necessary central area required for uniform colour switching, while the peripheral rim portion remains uncovered. This localized coverage reduces the total amount of electrochromic material and associated ion migration distance, thereby lowering switching voltage and power consumption while maintaining sufficient colour switch uniformity in the displayed symbol area.
3Area of moving object
If the electrochromic layer extends to the edges of the opening, then the displayed symbol has maximum area, but electronic short-circuits and cross-talk between segments increase
Solution Approach 1:
The electrochromic layer is confined to the central region and deliberately excluded from the peripheral rim portion surrounding each opening. This creates an uncovered insulating barrier between adjacent electrochromic regions, preventing electronic short-circuits and cross-talk while preserving maximum symbol display area within the uncovered rim configuration.
4Ease of manufacture
If conventional printing methods are used without optimization, then the manufacturing process is simple, but manufacturing yield is reduced due to smearing and short-circuits
Solution Approach 1:
The patent specifies precise spatial control of the electrochromic layer deposition to create the uncovered rim portion configuration. This design feature prevents smearing-induced short-circuits during conventional printing processes, as the uncovered rim acts as a natural barrier that contains the electrochromic material within defined boundaries. Consequently, standard printing methods can be used without sacrificing manufacturing yield.
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 results in a sharper image, lower switching voltage, reduced power consumption, and improved manufacturing yield, allowing for the use of a single battery and minimizing electronic short-circuits and cross-talk between display segments.
Implementation Method 1
each pixel or switchable segment is connected by a separate electric conduction line to an external drive voltage source, facilitating simultaneous individual electrical control of all pixels in the display... the display is arranged to change colour upon changing the oxidation state of said electrochromic layer
Implementation Method 2
The switching of electrochromic electrode materials is a faradic reaction, that is, ions must be able to move into or out from the electrode to compensate for changes in oxidation levels of the electrode material
Data Source
Figure 1a~1b
Figure 1c~1d
Figure 1e~1f
AI summary
There is provided a directly addressable display (100) for displaying a symbol having: a first electrochromic electrode material switchable between two coloring states (110); a symbol defining layer (120) with one opening (121) defining said symbol, an electrolyte layer (130) which fills and covers the opening of said symbol defining layer, a counter electrode comprising a carbon layer (140) and an EC layer (160). The EC layer is arranged in ionic contact with the electrolyte layer, and the carbon layer is arranged in physical contact with the EC layer, the spatial extension of the EC layer is smaller than the spatial extension of the opening in the symbol defining layer, thus leaving a rim portion (20) of the opening in the symbol defining layer uncovered by the EC layer, which uncovered rim portion partly or fully surrounds said EC layer and wherein said carbon layer preferably extends behind the electrolyte layer from the EC layer across the rim portion to the symbol defining layer.