Step Difference Compensation Pattern for OLED Gate Insulating Layers
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Solution Overview
Problem
Display devices face reliability issues due to step differences in the gate insulating layer, which can lead to shorting of thin film transistors (TFTs) and wiring lines during manufacturing, affecting the performance and reliability of organic light-emitting diode (OLED) displays.
Innovation Solution
A display device with a step difference compensation pattern formed between the gate wiring lines, made of the same material and thickness as the wiring lines, is integrated on the gate insulating layer to compensate for the step differences, preventing shorting and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gate insulating layer is formed on wiring lines during OLED manufacturing, then the insulating function is improved, but step differences cause shorting of TFTs and wiring lines
Solution Approach 1:
A step difference compensation pattern is formed on the gate insulating layer before forming the TFTs and wiring lines. This preliminary structure compensates for the step differences created by the gate insulating layer, ensuring that subsequent layers can be formed without shorting issues. The compensation pattern is created at the right time in the manufacturing process to prevent problems before they occur.
Solution Approach 2:
The step difference compensation pattern acts as an intermediary structure between the gate insulating layer and the subsequent TFTs/wiring lines. It mediates the step difference problem by providing a transitional surface that eliminates the height discrepancy, allowing the insulating layer to maintain its function without causing shorting.
2Reliability
If the step difference compensation pattern is formed with the same material and thickness as wiring lines, then the shorting problem is solved, but the device complexity increases
Solution Approach 1:
The step difference compensation pattern uses the same material and formation process as the wiring lines, allowing it to serve multiple purposes: compensating for step differences and potentially functioning as part of the electrical circuit. This multi-functionality reduces the need for separate specialized structures, thereby limiting the increase in device complexity.
Solution Approach 2:
By controlling the thickness of the step difference compensation pattern to match the wiring line thickness (2,500 Å to 3,500 Å), the patent optimizes the parameter to achieve shorting prevention while maintaining compatibility with existing manufacturing processes and materials, thus minimizing the impact on device complexity.
Data Source
AI summary
A display device includes: a first wiring line and a second wiring line separated from each other on a substrate; a gate insulating layer on the first wiring line and the second wiring line; a step difference compensation pattern between the first wiring line and the second wiring line on the gate insulating layer; a protective layer on the step difference compensation pattern; and a pixel electrode on the protective layer.