OLED Display Cathode Resistance Reduction via Conductive Support
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Solution Overview
Problem
Top emission type OLED displays face issues with significant voltage drop (IR Drop) due to high cathode resistance, especially in large-sized displays, and rely on inorganic encapsulation layers for encapsulation, which cannot be used with auxiliary cathodes, affecting electrical connection and encapsulation performance.
Innovation Solution
A display device with a supporting body comprising monodisperse particles and a conductive layer, integrated with a moisture-absorbing layer, is used to electrically connect the transparent electrode and cathode, forming a conductive and barrier structure that reduces cathode resistance and prevents water and oxygen intrusion, even without an inorganic encapsulation layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic encapsulation layer is used for encapsulation, then encapsulation performance is improved, but electrical connection between transparent electrode and cathode deteriorates
Solution Approach 1:
The encapsulation structure is segmented into multiple functional layers: the inorganic encapsulation layer (first encapsulation layer) provides barrier protection, while the auxiliary cathode structure with conductive adhesive (second encapsulation layer) provides electrical connection. This segmentation allows each layer to perform its specific function without interfering with the other, resolving the contradiction between encapsulation performance and electrical connection.
Solution Approach 2:
The conductive adhesive serves as an intermediary material between the auxiliary cathode and the transparent electrode. It enables electrical connection while being compatible with the inorganic encapsulation layer, thus resolving the contradiction by providing a mediating substance that facilitates both encapsulation and conduction functions.
2Reliability
If cathode resistance is reduced by adding auxiliary cathode, then voltage drop is reduced, but device structure complexity increases
Solution Approach 1:
The auxiliary cathode structure performs multiple functions: it serves as an electrical conductor to reduce resistance and voltage drop, while simultaneously functioning as part of the encapsulation system by being covered with conductive adhesive and positioned within the sealing region. This multi-functionality reduces the need for separate components, thereby limiting the increase in overall device complexity.
Solution Approach 2:
The auxiliary cathode is merged with the transparent electrode and conductive adhesive to form an integrated electrical connection system. By combining these elements into a unified structure within the sealing region, the design reduces the number of discrete components and simplifies the overall device architecture while achieving the goal of reducing cathode resistance.
3Area of stationary object
If top emission type OLED is used, then aperture ratio is improved, but cathode resistance increases causing voltage drop
Solution Approach 1:
The auxiliary cathode extends in the horizontal dimension across the display region, providing additional conduction pathways parallel to the light emission direction. This dimensional addition creates multiple conduction routes that reduce overall resistance without blocking the vertical light path, thus maintaining high aperture ratio while improving voltage stability.
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 effectively reduces cathode resistance, improves display quality, and maintains encapsulation performance by blocking water vapor and oxygen, while allowing for a narrow bezel design.
Implementation Method 1
a moisture absorbing layer arranged at a periphery of the monodisperse particles, the moisture absorbing layer being configured to prevent external moisture from entering the display device
Implementation Method 2
a conductive layer wrapping the monodisperse particles, the transparent electrode and the cathode being electrically conducted through the conductive layer
Data Source
AI summary
The present disclosure provides a display device and a method for preparing the same. The display device includes a first base; a transparent electrode arranged on the first base; a display substrate arranged on a side of the first base proximate to the transparent electrode and opposite to the first base, the display substrate comprising a cathode located on a side of the display substrate proximate to the first base; and a supporting body located between the transparent electrode and the cathode and configured to electrically conduct the transparent electrode and the cathode.