OLED Pixel Drive Circuit with Parallel Transistors for Luminance Control
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Solution Overview
Problem
OLED display panels using oxide transistors face challenges with smaller subthreshold swing, leading to poor luminance control and display effects, especially when displaying low grayscale images.
Innovation Solution
A pixel driving circuit is designed with a drive circuit comprising two drive transistors connected in parallel, where the subthreshold swing of one transistor is greater than the other, allowing for neutralization of subthreshold swings and improved luminance control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If oxide transistors are used in OLED display panels, then the transistor can be manufactured with good mobility, but the subthreshold swing becomes smaller leading to poor luminance control
Solution Approach 1:
The drive circuit is segmented into two parallel drive transistors (first drive transistor and second drive transistor) with different subthreshold swings. This segmentation allows each transistor to contribute differently to the overall driving current, enabling precise control of the subthreshold swing characteristic while maintaining high mobility through the parallel configuration.
Solution Approach 2:
The invention changes the subthreshold swing parameter by using two transistors with different subthreshold swing values. The first drive transistor has a first subthreshold swing and the second drive transistor has a second subthreshold swing, and their parallel combination produces a composite subthreshold swing that is greater than either individual transistor, thereby improving luminance control precision.
2Device complexity
If a single drive transistor is used, then the circuit structure is simple, but the subthreshold swing is insufficient for good luminance control
Solution Approach 1:
The drive circuit is divided into two parallel drive transistors with different subthreshold swings. This segmentation enables precise control of the composite subthreshold swing while keeping the overall circuit structure relatively simple, as the two transistors are connected in parallel and share common source and drain electrodes.
Solution Approach 2:
The invention merges two drive transistors with different subthreshold swing characteristics in parallel configuration. The combined effect of these two transistors produces a composite subthreshold swing that is greater than either individual transistor, achieving improved luminance control without requiring a completely new circuit architecture.
3Manufacturing precision
If transistors with larger subthreshold swing are used, then luminance control improves, but transistor mobility decreases
Solution Approach 1:
The invention changes the subthreshold swing parameter by combining two transistors with different subthreshold swing values. The first drive transistor has a first subthreshold swing and the second drive transistor has a second subthreshold swing, and their parallel combination produces a composite subthreshold swing that is greater than either individual transistor, thereby improving luminance control precision.
Solution Approach 2:
The drive circuit is segmented into two parallel drive transistors (first drive transistor and second drive transistor) with different subthreshold swings. This segmentation allows each transistor to contribute differently to the overall driving current, enabling precise control of the subthreshold swing characteristic while maintaining high mobility through the parallel configuration.
Data Source
AI summary
A pixel driving circuit is provided. The pixel driving circuit includes a light emission control circuit and a drive circuit. The light emission control circuit controls a potential of a control terminal of the drive circuit under the control of a coupled signal terminal, and the drive circuit drives a coupled light-emitting element to emit light based on the potential of the control terminal thereof. The drive circuit includes two drive transistors connected in parallel, and subthreshold swings of the two drive transistors are different.