Oxide TFT Pixel Circuit Layout for Stable Gate Voltage
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Solution Overview
Problem
Existing display devices face challenges in maintaining image quality due to voltage fluctuations in the gate electrode of driving transistors, which affect the luminance and overall performance of organic light emitting diodes.
Innovation Solution
The implementation of an oxide-based transistor structure, including a switching transistor and a compensation transistor with an oxide-based active layer, which reduces leakage current and minimizes voltage fluctuations, thereby improving image quality by connecting these transistors to a field effect transistor through a contact hole in an insulating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional transistors are used in the switching and compensation circuits, then the device complexity is reduced, but leakage current increases causing voltage fluctuations at the gate node
Solution Approach 1:
The patent changes the material parameter of the transistor from conventional semiconductor to oxide semiconductor, which fundamentally alters the electrical characteristics to achieve ultra-low leakage current and stable gate voltage
Solution Approach 2:
The patent employs oxide semiconductor materials (such as IGZO - indium gallium zinc oxide) that combine the advantages of wide bandgap semiconductors with transistor functionality, creating a composite material system that achieves both low leakage and stable operation
2Reliability
If oxide-based transistors are used to reduce leakage current, then voltage fluctuations are minimized, but the manufacturing precision requirements increase
Solution Approach 1:
The patent segments the transistor fabrication into distinct stages: forming oxide semiconductor layers through atomic layer deposition (ALD), creating patterned structures, and implementing multi-layer stacking, where each stage can be optimized and controlled independently to achieve high precision
Solution Approach 2:
The patent introduces oxide semiconductor layers as intermediary materials between the gate electrode and source/drain electrodes, which serve as a buffer to stabilize voltage and reduce the impact of manufacturing variations on overall device performance
3Device complexity
If the switching transistor and compensation transistor are integrated on the same layer, then the device complexity is reduced, but voltage control precision deteriorates
Solution Approach 1:
The patent transitions from planar integration to three-dimensional stacking, placing the switching transistor and compensation transistor on different layers connected through contact holes, which maintains electrical isolation and precise voltage control while achieving spatial integration
Data Source
AI summary
The present disclosure relates to a display device, and more particularly, to a display device capable of improving image quality by reducing or minimizing voltage fluctuations of a gate electrode of a driving transistor. The display device includes a substrate; a field effect transistor on the substrate; an oxide-based transistor on a layer different from the field effect transistor and connected to the field effect transistor through a contact hole in an insulating layer; and a pixel electrode on the oxide-based transistor.