Dual-Gate TFT Display Substrate for Stable Threshold Voltage
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Solution Overview
Problem
Current OLED display technologies face challenges in achieving optimal display performance and power efficiency, particularly in the design of thin film transistors, which affect the overall display substrate and panel performance.
Innovation Solution
The display substrate incorporates a dual-gate structure with oxide semiconductor and polysilicon semiconductor materials for the first and third transistors, respectively, along with a specific layer arrangement and conductive layer configuration to enhance display performance and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional LTPS TFT technology is used, then manufacturing process is simpler, but power consumption is higher by 5-15%
Solution Approach 1:
The transistor gate is divided into two separate gates (first gate electrode and second gate electrode) positioned at opposite interfaces of the active layer, creating a dual-gate structure. This segmentation allows independent control of threshold voltage and improved electrical characteristics, reducing power consumption by 5-15% compared to traditional LTPS TFTs while managing the increased structural complexity through systematic design
Solution Approach 2:
Different gate electrodes are assigned different materials and positions: the first gate electrode uses a conductive material at the lower interface, while the second gate electrode uses another conductive material at the upper interface. This local differentiation optimizes electrical field distribution and threshold voltage control in specific regions, achieving lower power consumption without requiring complete redesign of the entire transistor structure
2Stability of the object's composition
If dual-gate structure with oxide semiconductor is implemented, then threshold voltage stability improves, but manufacturing process complexity increases
Solution Approach 1:
The dual-gate structure serves multiple functions simultaneously: it provides threshold voltage control, improves subthreshold swing, enhances on-state current, and stabilizes threshold voltage against process variations. By integrating these functions into a single structural design, the patent achieves improved threshold voltage stability without requiring separate manufacturing processes for each function, thus managing manufacturing complexity
Solution Approach 2:
The active layer uses oxide semiconductor material (such as IGZO) which inherently provides stable threshold voltage characteristics. This composite material approach combines the benefits of oxide semiconductors (high stability) with the dual-gate structure (enhanced control), achieving superior threshold voltage stability while using materials and processes that are increasingly compatible with existing manufacturing capabilities
3Reliability
If multiple conductive layers are added for dual-gate structure, then display performance improves, but layer structure complexity increases
Solution Approach 1:
Instead of adding complexity in the planar direction, the patent utilizes the vertical dimension by positioning gate electrodes at opposite interfaces (upper and lower surfaces) of the active layer. This three-dimensional arrangement of the dual-gate structure enables improved electrical control and display performance while maintaining a compact footprint, effectively managing layer structure complexity through spatial optimization
Data Source
AI summary
A display substrate, a display panel, and a display device are provided. The display substrate includes: a base substrate; a first semiconductor layer on the base substrate; and a second semiconductor layer on a side of the first semiconductor layer away from the base substrate. The display substrate further includes a plurality of thin film transistors on the base substrate, which at least include a first transistor, a second transistor and a third transistor. Each of the plurality of thin film transistors includes an active layer. The active layer of at least one of the first transistor and the second transistor is located in the second semiconductor layer and contains an oxide semiconductor material. The active layer of the third transistor is located in the first semiconductor layer and contains a polysilicon semiconductor material. At least one of the first transistor and the second transistor has a dual-gate structure.