OLED Auxiliary Electrode Barrier Layer Voltage Uniformity
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Solution Overview
Problem
Large-area OLED displays face challenges in maintaining uniform luminance due to variations in power voltage across the active area, particularly in top emission type displays where the cathode's surface resistance leads to position-dependent luminance issues, making it difficult to apply existing solutions to high-resolution displays with small-sized pixels.
Innovation Solution
The implementation of a conductive filler layer with a low resistance material between substrates, including a spacer and auxiliary electrodes, to evenly distribute power voltage and reduce luminance variations, allowing for a uniform power supply to the cathode without increasing the complexity of pixel design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low potential power voltage line is formed on a lower substrate to prevent voltage drop, then voltage uniformity is improved, but device complexity increases due to additional connection areas required in each pixel
Solution Approach 1:
The patent merges the low potential power voltage line formation with the cathode structure by making the cathode itself serve as the power voltage line. The cathode is extended to directly contact the auxiliary electrode, eliminating the need for separate power voltage lines and reducing pixel complexity while maintaining voltage uniformity.
Solution Approach 2:
The cathode is designed to perform multiple functions: it serves both as the electron injection electrode for the OLED and as the low potential power voltage line. This multi-functionality eliminates the need for dedicated power voltage lines, reducing device complexity while ensuring uniform voltage distribution.
2Illumination intensity
If the cathode is formed with transparent conductive material to secure transmittance in top emission type displays, then light transmittance is improved, but surface resistance increases causing position-dependent luminance variation
Solution Approach 1:
The patent combines the cathode with the low potential power voltage line function, allowing the transparent conductive cathode to serve dual purposes. This integration ensures that even with high transmittance materials, the voltage distribution remains uniform by directly connecting the cathode to the auxiliary electrode.
Solution Approach 2:
The auxiliary electrode acts as an intermediary that provides a low resistance path for power voltage distribution. By contacting the auxiliary electrode, the cathode benefits from improved voltage uniformity without compromising its transparency and light transmittance properties.
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 solution achieves uniform luminance across the OLED display by reducing voltage variations and enabling the use of high-resolution displays with improved design flexibility, as it eliminates the need for additional connection areas and reduces manufacturing complexity.
Implementation Method 1
a conductive filler layer interposed between the first substrate and the second substrate, the conductive filler layer including a conductive medium
Data Source
AI summary
An organic light emitting diode display is disclosed. The organic light emitting diode display includes a first substrate, a second substrate, and a conductive filler layer between the first substrate and the second substrate. The first substrate includes an auxiliary electrode, a first barrier disposed on the auxiliary electrode, a cathode physically divided by the first barrier and exposing at least a portion of the auxiliary electrode, and a protective layer disposed on the cathode, physically divided by the first barrier, and exposing at least a portion of the auxiliary electrode. The second substrate includes a spacer protruding toward the first substrate and disposed adjacent to the auxiliary electrode and a power line covering at least a portion of the spacer and supplied with a power voltage.