Hybrid 2T1C OLED Drive Circuit for Uniform Brightness
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Solution Overview
Problem
Current 2T1C drive circuits for AMOLEDs face challenges in stability and uniformity of current signal conversion, leading to issues in large-size display screens, such as computer monitors and televisions, with complex production processes and high costs.
Innovation Solution
A new 2T1C drive circuit using an inorganic semiconductor material for the switch transistor and an organic semiconductor material for the drive transistor, with different carrier types, and employing specific connection modes and fabrication methods to achieve stable and uniform current signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a 2T1C drive circuit with silicon semiconductor transistor and organic semiconductor transistor is used, then the structure is simple and processing is easy, but the stability and uniformity of voltage-to-current signal conversion deteriorates
Solution Approach 1:
The patent applies local quality by using different semiconductor materials for different transistor types within the same circuit. Specifically, amorphous silicon semiconductor material is used for switch transistors while organic semiconductor material is used for drive transistors. This localized material differentiation optimizes each transistor's function: amorphous silicon provides stable switching characteristics, while organic semiconductor provides excellent current driving capability and uniformity, thereby resolving the contradiction between simple structure and reliable signal conversion.
2Reliability
If complicated compensating circuits (such as multi-T1C circuits) are used to provide constant uniform currents for OLEDs, then the current stability improves, but the production process becomes complex and yield reduces
Solution Approach 1:
The patent changes the material parameter of the semiconductor layer from uniform material to differentiated materials. By changing the semiconductor material type (amorphous silicon for switch transistors, organic semiconductor for drive transistors), the electrical characteristics are optimized to inherently provide stable and uniform current output without requiring additional compensating circuits. This parameter change resolves the contradiction by achieving current uniformity through material selection rather than circuit complexity.
3Device complexity
If 2T1C circuits are used for large-size display screens, then the device simplicity is maintained, but the display brightness uniformity deteriorates
Solution Approach 1:
The patent applies local quality by differentiating the semiconductor material used in drive transistors across the display screen. Organic semiconductor material is specifically used for drive transistors in large-size displays, which provides excellent charge carrier mobility and current uniformity across the entire screen area. This localized material application ensures uniform brightness across large displays while maintaining the simplicity of the 2T1C circuit structure.
Data Source
AI summary
There is provided an organic light-emitting diode drive circuit comprising a switch transistor (T1), a drive transistor (T2), a storage capacitor (C), and an organic light-emitting diode (OLED), wherein the switch transistor (T1) uses an inorganic semiconductor transistor, and the drive transistor (T2) uses an organic semiconductor transistor. A display screen adopting the drive circuit as a unit pixel has the property of uniform brightness. In addition, there is provided a method of fabricating the drive circuit and a display device using the drive circuit.