OLED Driving Transistor Fluorine Profile for Afterimage Reliability
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Solution Overview
Problem
Organic light emitting diode displays face challenges in maintaining reliability at high temperatures and reducing afterimages, with existing technologies struggling to balance these factors effectively.
Innovation Solution
The display device incorporates a driving transistor with a higher fluorine concentration than a switching transistor, and a barrier layer with varying fluorine concentrations, where the fluorine concentration in the driving transistor is 2 to 10 times that in the switching transistor, and 2 to 10 times in the barrier layer overlapping the driving transistor compared to the switching transistor, to improve afterimage quality and high-temperature reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fluorine concentration is increased in the driving transistor to improve afterimage performance, then afterimage quality improves, but high-temperature reliability deteriorates
Solution Approach 1:
The patent applies different fluorine concentrations to different transistor types within the same display device. Specifically, the driving transistor has a first fluorine concentration (2 to 10 times higher) while the switching transistor has a second fluorine concentration. This local differentiation allows the driving transistor to achieve better afterimage performance through higher fluorine content while the switching transistor maintains high-temperature reliability with lower fluorine content, thus resolving the technical contradiction.
2Manufacturing precision
If fluorine concentration is increased in the barrier layer overlapping the driving transistor to improve afterimage, then afterimage performance improves, but device complexity increases
Solution Approach 1:
The barrier layer is designed with spatially varying fluorine concentrations corresponding to the underlying transistor types. The barrier layer overlapping the driving transistor has a third fluorine concentration (2 to 10 times higher) while the barrier layer overlapping the switching transistor has a fourth fluorine concentration. This localized differentiation enables improved afterimage performance in the driving transistor region without unnecessarily complicating the entire barrier layer structure.
Solution Approach 2:
The barrier layer is effectively segmented into different regions with different fluorine concentrations based on the transistor types below. This segmentation allows independent optimization of each region's properties - the driving transistor region receives higher fluorine for afterimage improvement while the switching transistor region maintains lower fluorine for reliability, reducing overall device complexity compared to uniform high fluorine concentration.
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 improves afterimage performance while maintaining high-temperature reliability by selectively doping fluorine in the driving transistor and barrier layer, preventing luminance decrease and ensuring sufficient threshold voltage margin for switching operations.
Implementation Method 1
a first concentration of fluorine in the first semiconductor layer is higher than a second concentration of fluorine in the second semiconductor layer
Data Source
AI summary
An embodiment of the invention provides a display device including: a substrate; a first transistor comprising a first semiconductor layer and a second transistor comprising a second semiconductor layer, the first and second semiconductor layers positioned on the substrate; a light emitting diode connected to the first transistor, wherein: the first transistor is a driving transistor; the second transistor is a switching transistor; a first concentration of fluorine included in the first semiconductor layer is higher than a second concentration of fluorine in the second semiconductor layer; and a first difference between the first and second concentrations substantially at or near a first interface of the first and second semiconductor layers is larger than a second difference between the first and second concentrations at a second interface of the first and second semiconductor layers, the second interface further from the substrate than the first interface.