Transparent Nanostructure-Film Pixel Electrodes for Flexible Displays
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Solution Overview
Problem
Current transparent electrode materials like indium-tin-oxide (ITO) are brittle, inflexible, and challenging to fabricate on non-flat surfaces, with high-temperature deposition requirements and indium scarcity issues, limiting their suitability for pixelated devices such as LCDs and OLEDs.
Innovation Solution
The use of transparent conductive nanostructure-films composed of interconnected networks of carbon nanotubes, nanowires, and graphene flakes, which are more robust and flexible, and can be deposited using low-impact methods like solution-based processes, allowing for improved step coverage and adhesion on non-flat surfaces without damaging underlying layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ITO is used as transparent electrode material, then electrical conductivity and transparency are achieved, but mechanical robustness and flexibility are poor
Solution Approach 1:
The patent changes the material composition from brittle ITO to flexible carbon-based nanomaterials (graphene, carbon nanotubes, carbon nanofibers), fundamentally altering the physical and mechanical parameters of the transparent electrode to achieve both conductivity and flexibility
Solution Approach 2:
The patent employs composite carbon-based materials including graphene, carbon nanotubes, and carbon nanofibers in various combinations to create transparent electrodes that combine electrical conductivity, mechanical strength, and flexibility, replacing the single-material ITO approach
2Reliability
If ITO is deposited using high-temperature sputtering, then electrical properties are improved, but compatibility with device processes and cost are worsened
Solution Approach 1:
The patent replaces the mechanical sputtering deposition process with solution-based chemical methods for depositing carbon-based transparent electrodes, eliminating the need for high-temperature vacuum equipment and enabling compatibility with flexible substrates and lower-cost manufacturing
Solution Approach 2:
The patent utilizes abundant carbon-based materials (graphene, carbon nanotubes) that can be deposited using inexpensive solution processing methods, replacing expensive ITO and high-cost sputtering equipment with cheaper alternatives that maintain electrical performance
3Area of stationary object
If ITO is fabricated on non-flat surfaces, then pixel electrode coverage is achieved, but patterning precision and adhesion are worsened
Solution Approach 1:
The patent employs flexible carbon-based nanomaterial films (graphene, carbon nanotubes) that can conform to non-flat TFT substrate surfaces, maintaining excellent adhesion and patterning precision where rigid ITO fails due to its brittleness and inability to follow surface contours
4Reliability
If intermediate protection layers are used to deposit pixel electrodes, then underlying layers are protected, but fabrication complexity and time are increased
Solution Approach 1:
The patent extracts and eliminates the intermediate protection layer from the fabrication process by using carbon-based nanomaterials that can be directly deposited on underlying layers without causing damage, simplifying the manufacturing process while maintaining layer integrity
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
These nanostructure-films provide comparable electrical properties to ITO while being more mechanically robust, reducing the risk of defects and enabling flexible displays, with reduced fabrication complexity and cost by eliminating the need for intermediate protection layers and allowing for the same-layer formation of pixel and TFT electrodes.
Implementation Method 1
fabrication of ITO components on non-flat surfaces (e.g., TFT substrates) can be extremely challenging with respect to patterning, adhesion and step-coverage. Furthermore, the indium component of ITO is rapidly becoming a scarce commodity, and ITO deposition usually requires expensive, high-temperature sputtering
Implementation Method 2
transparent conductive nanostructure-films composed of randomly distributed carbon nanotubes (e.g., networks of substantially single-walled nanotubes (SWNTs), double-walled nanotubes (DWNTs) and/or few-walled nanotubes (FWNTs))
Implementation Method 3
Nanostructure-films comprising, for example, interconnected networks (e.g., having a density above a percolation threshold) of nanotubes, nanowires, nanoparticles and/or graphene flakes, have attracted a great deal of recent attention due to their exceptional material properties. In particular, transparent conductive nanostructure-films
Data Source
AI summary
A pixel electrode is provided, with a nanostructure-film deposited over an active matrix substrate, such that the pixel electrode makes electrical contact with an underlying layer. Similarly, auxiliary data pads and auxiliary gate pads are provided, which also have nanostructure-films deposited over an active matrix substrate, such that they make electrical contact with underlying layers.