Hybrid Oxide and LTPS Transistor Pixel Circuit for Display Stability
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Solution Overview
Problem
Current OLED display panels using low-temperature polysilicon thin-film transistors exhibit poor stability in the pixel driving circuit, particularly at lower refresh frequencies, leading to unstable light emission and poor display effects.
Innovation Solution
A display panel design incorporating a pixel driving circuit with oxide transistors for compensation, initialization, and light-emitting control, combined with low-temperature polysilicon transistors for switching and driving, which includes a compensation transistor to stabilize threshold voltage and improve leakage current characteristics, enhancing circuit stability and display performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If low-temperature polysilicon thin-film transistors are used to drive pixels, then high mobility and fast response are achieved, but stability in the light-emitting phase at lower refresh frequency deteriorates
Solution Approach 1:
The pixel driving circuit is segmented into different transistor types performing different functions: oxide transistors handle initialization and compensation tasks requiring stability, while low-temperature polysilicon transistors handle switching and driving tasks requiring speed. This functional segmentation allows each component to be optimized for its specific role.
Solution Approach 2:
Different regions of the pixel driving circuit are assigned different transistor materials with tailored properties. The oxide transistor region provides stable threshold voltage and low leakage for initialization and compensation, while the low-temperature polysilicon transistor region provides high mobility for rapid switching and driving operations.
2Reliability
If oxide transistors are used for compensation and initialization, then threshold voltage stability and leakage current reduction are achieved, but device complexity increases
Solution Approach 1:
The oxide transistor is designed to perform multiple functions: initialization, compensation, and light-emitting control. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby managing complexity while achieving stable threshold voltage and reduced leakage current.
Solution Approach 2:
Multiple functions (initialization and compensation) are merged into a single oxide transistor component, reducing the overall number of components needed and simplifying the circuit structure while maintaining reliability through the inherent stability of oxide transistor characteristics.
3Reliability
If multiple transistor types are combined, then circuit stability and display quality are improved, but manufacturing complexity increases
Solution Approach 1:
The patent addresses manufacturing complexity by organizing the different transistor types in a layered dimensional structure, with oxide transistors and low-temperature polysilicon transistors formed in separate layers. This dimensional separation allows independent optimization and fabrication processes for each transistor type while maintaining overall circuit functionality.
Data Source
AI summary
A display panel and a display device are provided. The display panel includes a plurality of light-emitting devices and a pixel driving circuit for driving the light-emitting devices to emit light. By using oxide transistors as a compensation transistor, first initialization transistor, and second initialization transistor in the pixel driving circuit, and using low-temperature polysilicon transistors as other transistors, both low leakage current characteristics of the oxide transistors and high mobility characteristics of the low-temperature polysilicon transistors can be achieved, making the circuit more stable.