OLED Cathode Power Distribution via Conductive Filler Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Large-area organic light emitting diode display devices face issues with luminance non-uniformity due to voltage drops across the cathode, particularly in top emission types, leading to position-dependent luminance deviations, and existing solutions complicate manufacturing and increase costs.
Innovation Solution
An organic light emitting diode display device with a conductive filler layer connecting the cathode to power supply wiring, using a low-resistance material to reduce voltage drops and simplify the connection structure, allowing for uniform power distribution across the display area without additional complex processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a transparent conductive material such as ITO or a very thin opaque conductive material is used for the cathode in top emission type display devices, then transmittance is secured, but surface resistance becomes large and luminance deviation depending on position becomes remarkably large
Solution Approach 1:
An Evss wiring layer with low surface resistance is introduced as an intermediary component between the power supply voltage source and the cathode. This wiring layer compensates for the high resistance of the transparent conductive cathode material, maintaining both transmittance and luminance uniformity by providing an alternative low-resistance power distribution path.
Solution Approach 2:
The cathode structure is designed with spatially varying properties: the transparent conductive material is used where transmittance is critical, while the Evss wiring is strategically positioned in specific regions to provide localized resistance compensation. This allows different parts of the cathode to have optimized characteristics for their specific functional requirements.
2Manufacturing precision
If Evss wiring including low-resistance material is formed and connected to the cathode to prevent voltage drop, then luminance uniformity is improved, but connection structure becomes complicated and additional processes such as forming partition are required
Solution Approach 1:
The Evss wiring layer is designed to serve multiple functions simultaneously: it provides low-resistance power distribution to the cathode, acts as an encapsulation layer protecting underlying structures, and can be integrated with existing manufacturing processes. This multi-functionality reduces the need for separate dedicated Evss wiring structures and partitions.
Solution Approach 2:
The Evss wiring formation process is merged with existing manufacturing steps such as the encapsulation layer formation or color filter fabrication. By combining multiple functions into a single integrated structure and process flow, the overall device complexity is reduced while maintaining luminance uniformity.
3Manufacturing precision
If Evss wiring is formed on first substrate, then voltage drop is prevented, but connecting area of Evss wiring and cathode must be allocated in one pixel, making it difficult to apply to high-resolution display device with small single pixel size
Solution Approach 1:
The Evss wiring structure is transitioned from a planar two-dimensional layout to a three-dimensional stacked configuration. By forming the Evss wiring on a separate second substrate and bonding it to the first substrate, the wiring can extend across multiple pixels without consuming pixel area, enabling high-resolution displays with sufficient power distribution capability.
Solution Approach 2:
The display device is divided into multiple layers with distinct functions: the first substrate contains the active pixel elements, while the second substrate contains the Evss wiring. This segmentation allows the power distribution function to be separated from the pixel formation function, preventing Evss wiring from occupying valuable pixel area.
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 luminance non-uniformity, simplifies manufacturing, and enables the production of high-resolution displays by ensuring consistent power supply to each pixel, improving yield and reducing manufacturing time and costs.
Implementation Method 1
a conductive filler layer interposed between the first substrate and the second substrate and having a conductive medium. A cathode of the organic light emitting diode and the power supply wiring are electrically connected through the conductive filler layer
Implementation Method 2
The organic light emitting diode includes an anode, a cathode, and an organic light emitting layer disposed therebetween. In the organic light emitting diode display device, holes and electrons injected from the anode and the cathode, respectively, are combined in the organic light emitting layer to form excitons. The formed excitons emit light while falling from an excited state to a ground state and display an image.
Data Source
AI summary
An organic light emitting diode display device is disclosed. The organic light emitting diode display device includes a first substrate having a plurality of pixels in which a thin film transistor and an organic light emitting diode connected to the thin film transistor are arranged, a second substrate having a power supply wiring to which a power supply voltage is applied, and a conductive filler layer interposed between the first substrate and the second substrate and having a conductive medium. A cathode of the organic light emitting diode and the power supply wiring are electrically connected through the conductive filler layer.