Pixel Driving Circuit Using Oxide TFTs for Low-Refresh Stability
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Solution Overview
Problem
Current OLED display panels using low-temperature polysilicon thin-film transistors exhibit poor stability in pixel driving circuits, 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 and initialization, combined with low-temperature polysilicon transistors for switching and control, which includes specific transistor configurations and layer structures to enhance stability and mobility, utilizing storage capacitors and blocking members to manage threshold voltages and leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If low-temperature polysilicon thin-film transistors are used in pixel driving circuits, then high mobility is achieved, but stability deteriorates at lower refresh frequencies
Solution Approach 1:
The pixel driving circuit is segmented into two types of transistors: low-temperature polysilicon transistors (T1-T6) for switching and control functions requiring high mobility, and oxide transistors (T7-T10) for compensation and initialization functions requiring low leakage and high stability. This segmentation allows each transistor type to be optimized for its specific function, resolving the contradiction between mobility and stability.
Solution Approach 2:
Different transistor types are assigned to different locations within the pixel driving circuit based on functional requirements. Oxide transistors with low leakage characteristics are placed in compensation (T7) and initialization (T8-T10) circuits where stability is critical, while low-temperature polysilicon transistors with high mobility are used in switching (T2) and driving (T1) circuits where fast response is needed.
2Reliability
If oxide transistors are used for compensation and initialization, then leakage current is reduced and stability is improved, but device complexity increases
Solution Approach 1:
The patent merges two different transistor technologies (low-temperature polysilicon and oxide semiconductors) into a single pixel driving circuit. This combination allows the circuit to simultaneously achieve high mobility (from polysilicon transistors) and low leakage/high stability (from oxide transistors), resolving the contradiction between stability and device complexity by making each transistor type perform its specialized function.
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.