OLED TFT Layout With Light Blocking for Oxide Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing organic light emitting display devices face issues with damage and variations in oxide semiconductor thin film transistors due to external light, leading to increased luminance and reliability concerns.
Innovation Solution
The implementation of a multi-type thin film transistor structure on a single substrate, including a low temperature poly-silicon (LTPS) thin film transistor and an oxide semiconductor thin film transistor, with a light blocking layer and protrusion patterns to prevent light exposure and electrical charge interference, thereby reducing damage and variations in oxide semiconductor elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-type thin film transistor structure is implemented with both LTPS and oxide semiconductor transistors on the same substrate, then device performance and operating characteristics are improved, but the complexity of the device structure increases
Solution Approach 1:
The pixel circuit is divided into multiple functional blocks, each implemented with different transistor types optimized for specific functions. The driving transistor uses LTPS for high mobility requirements, while switching transistors use oxide semiconductor for low leakage requirements, allowing each segment to be optimized independently for its specific operational demands.
Solution Approach 2:
Different regions of the device are assigned different transistor types based on local functional requirements. The driving transistor region employs LTPS technology for high current drive capability, while the switching transistor regions employ oxide semiconductor for low off-state current, creating a heterogeneous structure where each local area has the appropriate material properties for its specific function.
2Ease of manufacture
If oxide semiconductor thin film transistors are exposed to external light, then manufacturing is simplified, but the oxide semiconductor elements suffer damage and variations leading to increased luminance and reduced reliability
Solution Approach 1:
A light-blocking layer is introduced as an intermediary component between the external environment and the oxide semiconductor transistor. This layer selectively blocks harmful light wavelengths that would otherwise reach and damage the oxide semiconductor elements, while allowing the manufacturing process to remain simplified and the device to maintain its intended functionality.
Solution Approach 2:
The light-blocking layer is positioned and configured in advance to prevent light-induced damage before it can occur. By establishing this protective barrier during the manufacturing process, the design proactively counteracts the harmful effects of external light exposure on oxide semiconductor elements, preventing rather than correcting potential reliability issues.
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 enhances the reliability and performance of the display device by blocking external light and preventing electrical charge interference, resulting in improved operating characteristics and reduced damage to oxide semiconductor thin film transistors.
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.