Vertical Electrochromic Display Ion Migration Control
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Solution Overview
Problem
Directly addressed electrochromic displays face challenges in achieving sharp images due to ion migration and diffusion, leading to blurred symbols and reduced image quality.
Innovation Solution
A directly addressable display device utilizing a polycationic electrolyte and a printable ionically isolative symbol defining layer, which restricts ionic migration and diffusion, ensuring sharper images by attracting large ion-complexes vertically through the electrochromic layer, and immobilizing small polymerizable molecules during curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional electrolyte with small mobile ions is used in directly addressed electrochromic displays, then the electrochromic switching function is achieved, but ion migration and diffusion cause blurred symbols and reduced image sharpness
Solution Approach 1:
The patent changes the fundamental parameter of ion size in the electrolyte by using large ion-complexes instead of small ions. This parameter change prevents ion migration and diffusion that cause blurring, while still enabling electrochromic switching through vertical ion transport. The large size of the ion-complexes physically restricts their ability to migrate laterally, thereby improving image sharpness.
Solution Approach 2:
The patent employs a composite electrolyte system comprising large ion-complexes combined with small polymerizable molecules. The ion-complexes provide the necessary ionic conductivity for electrochromic switching, while the polymerizable molecules form a matrix that further restricts ion migration. This composite approach addresses both the need for electrochromic function and the need to prevent blurring.
2Manufacturing precision
If large ion-complexes are used in the electrolyte to restrict ion migration, then image sharpness is improved, but the complexity of the electrolyte composition increases
Solution Approach 1:
The patent simplifies the electrolyte composition by focusing on a single key parameter change - using large ion-complexes - rather than incorporating multiple complex components. This parameter change alone provides sufficient restriction on ion migration to improve image sharpness, avoiding the need for overly complex electrolyte formulations.
Solution Approach 2:
The large ion-complexes inherently provide the restriction on ion migration through their physical size alone, without requiring additional complex structural features or multiple components. The size of the ion-complexes self-regulates their own migration behavior, preventing blurring while maintaining electrochromic functionality.
3Manufacturing precision
If small polymerizable molecules are added to the electrolyte to immobilize during curing, then image sharpness is improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent uses small polymerizable molecules that undergo a simple phase change from mobile to immobilized through polymerization. This parameter change (mobility state) is achieved through a straightforward curing process, adding minimal complexity to manufacturing while effectively restricting ion migration to improve image sharpness.
Solution Approach 2:
The patent exploits the phase transition of polymerizable molecules from a mobile liquid state to an immobilized cross-linked network through polymerization. This phase transition occurs during a simple curing process and effectively restricts ion migration without complicating the manufacturing process, as the transition is driven by a straightforward chemical reaction.
4Manufacturing precision
If vertical ion transport is promoted while lateral migration is restricted, then color contrast is improved, but the electrochromic switching speed may be affected
Solution Approach 1:
The patent changes the size parameter of the mobile ions to large ion-complexes, which promotes vertical transport through the electrochromic layer while restricting lateral migration. The vertical transport path is maintained through direct ionic contact between the electrolyte and electrochromic layer, ensuring adequate switching speed despite the larger ion size.
Solution Approach 2:
The patent effectively segments the ion transport pathways by restricting lateral migration while maintaining vertical transport. The large ion-complexes are confined to vertical movement between the electrolyte and electrochromic layer, creating distinct transport segments that prevent lateral diffusion and improve color contrast while maintaining switching functionality.
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 sharper image display with improved color contrast and reduced blurring, enabling efficient mass production without the need for expensive clean room facilities, while maintaining image retention and longevity.
Implementation Method 1
attracting large ion-complexes vertically through the electrochromic layer
Implementation Method 2
restricts ionic migration and diffusion
Implementation Method 3
immobilizing small polymerizable molecules during curing
Implementation Method 4
the display is arranged to change colour upon reduction of said electrochromic layer
Data Source
Figure 1a
Figure 1b~1c
Figure 1d~1e
AI summary
A directly addressable display device comprising at least one pixel cell (1-9), each pixel cell (1-9) being arranged for displaying a symbol, which symbol is repeatedly switchable between an on-state and an off-state, wherein each pixel cell (1-9) comprises an electrochromic layer (110) comprising an electrochromic and electrochemically active organic polymer material being electrochemically switchable between two different visually detectable coloring states; a counter electrode layer (140) comprising an electronically conductive material, wherein said counter electrode layer (140) in the viewing direction of the display device is arranged behind said electrochromic layer (110); an electrolyte layer (130), which electrolyte layer (130) is solid and arranged spatially between, and in ionic contact with, said electrochromic layer (110) and said counter electrode layer (140); a symbol defining layer (120) which is electronically and ionically insulating, arranged in direct ionic contact with said electrochromic layer (110), and which comprises one or more openings (121-129) which encloses said electrolyte layer (130) and defines the shape of said symbols; wherein said electrolyte layer (130) comprises a composition comprising a polyelectrolyte selected from one or more cationic polymers, wherein the electrolyte is substantially free of small cations.