Display Device Aperture Ratio via Reverse Tapered Barrier Rib
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Solution Overview
Problem
The challenge in display devices is to enhance aperture ratio and transmissivity while reducing manufacturing costs, particularly in transparent organic light-emitting displays where the sub-pixels and transmissive portions are in a trade-off relationship, making it difficult to increase both simultaneously.
Innovation Solution
The solution involves increasing the area of contact between the second electrode and the auxiliary electrode by using a reverse tapered shape for at least one of the barrier ribs, which allows for improved electrical connection and reduced contact resistance, thereby enhancing the aperture ratio and transmissivity without increasing the size of the sub-pixels or reducing the transmissive portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the sub-pixels are made larger to improve aperture ratio, then the transmissive portion gets smaller, but transmissivity deteriorates
Solution Approach 1:
The invention transitions from a two-dimensional planar contact between electrodes to a three-dimensional contact structure where the second electrode wraps around the side surface of the barrier rib. This vertical dimension addition increases the contact area without expanding the horizontal footprint, thereby improving transmissivity while maintaining the sub-pixel size and aperture ratio.
Solution Approach 2:
The second electrode is positioned to surround and make contact with the connecting electrode near the barrier rib, creating a nested contact configuration. This nested arrangement maximizes the contact interface between electrodes within the limited space, enhancing electrical connection and transmissivity without increasing the overall device area.
2Reliability
If the contact area between second electrode and auxiliary electrode is increased to improve transmissivity, then the sub-pixel size must increase, but aperture ratio deteriorates
Solution Approach 1:
The barrier rib is designed with a specific height that enables the second electrode to contact the connecting electrode from the side surface. This vertical structure allows increased contact area without increasing the horizontal area occupied by the sub-pixel, thus improving transmissivity while maintaining aperture ratio.
3Reliability
If the contact area between electrodes is increased to reduce contact resistance, then manufacturing complexity increases, but ease of manufacture deteriorates
Solution Approach 1:
The barrier rib height is optimized to provide sufficient contact area between the second electrode and connecting electrode. By controlling this geometric parameter, the invention achieves low contact resistance through a straightforward structural design that can be manufactured using standard fabrication processes, avoiding excessive manufacturing complexity.
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 configuration improves the aperture ratio and transmissivity of the transmissive portion, leading to better color fidelity and reduced manufacturing costs by optimizing the contact area between electrodes, thus addressing the trade-off between sub-pixels and transmissive portions.
Implementation Method 1
the organic light-emitting displays are self-luminous devices, and have fast response time, high light emission efficiency, great brightness
Data Source
AI summary
A display device can include a thin-film transistor (TFT) and an auxiliary electrode disposed on a substrate and spaced apart from each other, a passivation layer disposed on the TFT and the auxiliary electrode, a first barrier rib and a second barrier rib disposed on the passivation layer and spaced apart from each other, a first electrode disposed on the first barrier rib and connected to the TFT, a connecting electrode disposed on the second barrier rib and connected to the auxiliary electrode, a bank layer disposed on the passivation layer and including a first opening exposing a portion of the first electrode and a second opening exposing a portion of the connecting electrode, an organic emitting layer disposed on the first electrode and separated by the second barrier rib, and a second electrode disposed on the organic emitting layer and contacting the connecting electrode near the second barrier rib.