Display Cathode Segmentation for Leakage Current Control
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Solution Overview
Problem
Existing display apparatuses face issues with leakage current, leading to unintended light emission from some light emitting diodes, which affects color reproduction and image quality, especially at low gray scales.
Innovation Solution
The display apparatus incorporates a design where the first patterns are disposed to overlap the DC lines, increasing the path length for leakage current and forming capacitors to trap carriers, thereby reducing leakage current and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a common layer is used in light emitting diodes, then manufacturing complexity is reduced and production efficiency is improved, but leakage current increases causing unintended light emission
Solution Approach 1:
The common layer is segmented into multiple portions by introducing first patterns (trenches) that divide the continuous common layer into separate segments. This segmentation increases the resistance of the common layer, thereby reducing leakage current while maintaining the manufacturing advantages of using a common layer across multiple light emitting diodes.
2Reliability
If the path length for leakage current is increased, then leakage current is reduced, but device structure becomes more complex
Solution Approach 1:
The first patterns extend in the thickness direction (vertical dimension) to create trenches that increase the path length for leakage current. This dimensional approach allows increasing resistance without significantly increasing planar complexity, as the patterns are formed vertically between the anode and cathode.
3Reliability
If capacitors are formed to trap carriers, then leakage current is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The capacitors are formed self-service by utilizing the existing DC lines and the geometric configuration of the first patterns. The capacitors form automatically where the first patterns overlap with DC lines, eliminating the need for separate capacitor formation steps and reducing manufacturing precision requirements.
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 effectively minimizes leakage current, reduces unintended light emission, and enhances color reproduction and image quality, particularly at low gray scales, by increasing the resistance of the common layer and trapping leakage current carriers.
Implementation Method 1
increasing the resistance of the common layer and trapping leakage current carriers
Implementation Method 2
forming capacitors to trap carriers
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
Provided is a display apparatus. The display apparatus includes: a substrate in which a plurality of sub pixels is defined; a plurality of light emitting diodes which is disposed in the plurality of sub pixels and shares an organic layer and a cathode; a bank which is disposed below the cathode between the plurality of light emitting diodes; a plurality of wiring lines disposed between the bank and the substrate; and a first pattern which is disposed in the bank and overlaps at least one of the plurality of wiring lines, and the cathode is disposed in the first pattern. Accordingly, the length of the cathode and the organic layer in the first pattern is increased so that the length of the path through which the leakage current flows is increased, which may minimize the degradation of the display quality due to the leakage current.