Multi-Type TFT OLED Structure With Light Blocking for Oxide Stability
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Solution Overview
Problem
Existing organic light emitting display devices face issues with damage to semiconductor elements and variations in oxide semiconductor elements due to external light, leading to inconsistent performance.
Innovation Solution
The proposed solution involves an organic light emitting display device with a substrate structure that includes a first and second substrate separated by an inorganic insulating layer, featuring multiple thin film transistors with different semiconductor materials. A light blocking layer is disposed under the oxide semiconductor layer to prevent light-induced damage, and protrusion patterns are formed to enhance light blocking efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If oxide semiconductor thin film transistors are formed on the same substrate as other thin film transistors, then device integration and functionality are improved, but the oxide semiconductor elements suffer damage and variations due to external light
Solution Approach 1:
A light blocking layer is introduced as an intermediary element between the external light environment and the oxide semiconductor thin film transistor. This layer selectively blocks harmful light wavelengths that cause degradation of the oxide semiconductor material, while allowing the device to maintain its integrated functionality. The light blocking layer acts as a mediator that protects the sensitive oxide semiconductor elements without interfering with the overall device operation.
2Reliability
If multiple thin film transistors with different semiconductors are formed on different layers, then operating characteristics of pixels are improved, but damage to semiconductor elements occurs during formation
Solution Approach 1:
The light blocking layer is formed in advance, before the oxide semiconductor thin film transistor is manufactured. This preliminary action prevents light-induced damage to the oxide semiconductor material during the formation process and subsequent operation. By establishing the protective barrier beforehand, the integrity of the semiconductor elements is preserved while enabling the formation of multiple thin film transistors with different semiconductors on different layers.
3Device complexity
If no light blocking layer is used, then device structure remains simple, but oxide semiconductor elements exhibit current rise and luminance increase due to external light
Solution Approach 1:
The light blocking layer serves as a protective intermediary that is integrated into the device structure. While it does add a layer to the device, it prevents significant performance degradation and reliability issues that would occur without it. The addition of this relatively thin layer is justified by the substantial improvement in oxide semiconductor element stability and prevention of light-induced current rise and luminance variations.
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 effectively reduces damage to thin film transistors, particularly those made of oxide semiconductors, thereby improving the reliability and consistency of the display device by preventing variations caused by external light.
Implementation Method 1
A light blocking layer overlapping a lower portion of the second active layer and formed on the same layer as the second capacitor electrode
Data Source
AI summary
An organic light emitting display device may include a first thin film transistor including a first active layer formed of a first material and includes a first source region, a first channel region, and a first drain region, a first gate electrode and a first source electrode and a first drain electrode, a second thin film transistor including a second active layer formed of a second material and includes a second source region, a second channel region, and a second drain region, a second gate electrode, and a second source electrode and a second drain electrode, a light blocking layer overlapping a lower portion of the second active layer and formed on the same layer as the second capacitor electrode, and a first protrusion pattern and a second protrusion pattern disposed on the same layer as the first gate electrode and overlapping the light blocking layer.