Cathode Scan Line Segmentation for OLED Brightness Uniformity
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Solution Overview
Problem
Organic electroluminescent devices suffer from brightness variations and pectination due to line resistance differences between cathode electrode layers, leading to noticeable brightness differences and display quality issues.
Innovation Solution
The device incorporates a configuration where cathode electrode layers are connected to scan lines extending in different directions, ensuring equal electric potentials at both ends of at least one cathode electrode layer, which reduces line resistance differences and minimizes brightness variations between pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If scan lines are extended in a single direction to connect cathode electrode layers, then the device structure is simpler, but line resistance differences cause brightness variations and pectination
Solution Approach 1:
The scan lines are segmented into multiple groups extending in different directions (first direction and second direction). By dividing the scan line configuration into multiple directional segments, the patent reduces the line resistance differences that cause brightness variations, thereby resolving the contradiction between structural simplicity and brightness uniformity.
Solution Approach 2:
Different regions of the display panel are assigned scan lines with different extension directions. Specifically, some cathode electrode layers are connected via scan lines extending in a first direction while others are connected via scan lines extending in a second direction. This local differentiation optimizes the electrical characteristics in each region, eliminating brightness variations caused by uniform single-direction scan lines.
2Ease of manufacture
If cathode electrode layers are connected to scan lines in a uniform configuration, then manufacturing is easier, but line resistance differences create noticeable brightness differences between pixels
Solution Approach 1:
The connection configuration is segmented into multiple types: some cathode electrode layers are connected to scan lines extending in a first direction, while others are connected to scan lines extending in a second direction. This segmentation allows each group to be optimized independently, reducing line resistance differences and improving brightness uniformity without significantly complicating the manufacturing process.
Solution Approach 2:
The patent introduces a directional dimension to the scan line configuration by using scan lines that extend in different directions (first direction and second direction) to connect different cathode electrode layers. This dimensional variation in the connection architecture reduces line resistance differences and improves brightness uniformity while maintaining ease of manufacture.
3Shape
If all cathode electrode layers are connected to scan lines extending in the same direction, then the device structure is more regular, but pectination occurs due to accumulated line resistance differences
Solution Approach 1:
The scan line arrangement is segmented into multiple directional groups rather than using a single uniform direction. By dividing the scan lines into those extending in a first direction and those extending in a second direction, the patent prevents the accumulation of line resistance differences that cause pectination, while maintaining a relatively regular and systematic overall structure.
Solution Approach 2:
Different local regions of the display panel are assigned different scan line extension directions to prevent pectination. By making the scan line arrangement direction-dependent on the specific cathode electrode layer being connected, the patent eliminates the harmful pectination effect while preserving overall structural regularity through systematic configuration.
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 eliminates visually recognizable brightness differences between pixels, thereby enhancing display quality by preventing pectination and achieving uniform illumination.
Implementation Method 1
Organic electroluminescence is a phenomenon wherein excitons are formed in an organic (low molecular or high molecular) material thin film by re-combining holes injected through an anode with electrons injected through a cathode, and a light of specific wavelength is generated by energy from thus formed excitons.
Data Source
AI summary
An organic electroluminescent device having an improved display quality without pectination is provided. The organic electroluminescent device comprises a plurality of the cathode electrode layers comprising a plurality of first cathode electrode layers, wherein one end of each first cathode electrode layer is connected to one of the scan lines extending in the first direction; a plurality of second cathode electrode layers, wherein one end of each second cathode electrode layer is connected to one of the scan lines extending in the second direction; and at least one third cathode electrode layer, wherein one end of each third cathode electrode layer is connected to one of the scan lines extending in the first direction, and the other end of each third cathode electrode layer is connected to one of the scan lines extending in the second direction.