Stacked Thin Film Transistors With Shared Active Layer for Narrow Bezel Displays
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Solution Overview
Problem
The existing thin film transistor structures in display panels occupy a large area, which hinders the achievement of a narrow-bezel design and reduces the aperture ratio of the display panel, as multiple transistors are required for the Gate Driver on Array (GOA) technique.
Innovation Solution
A thin film transistor structure is developed where two transistors, a bottom-gate and a top-gate transistor, share a common active layer, allowing them to be stacked and reducing the overall area occupied, with the transistors' electrodes and contacts formed in a cross-shaped configuration to minimize space and simplify manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple thin film transistors are formed in the GOA circuit, then the gate driver function is achieved, but the area occupied by the GOA circuit increases
Solution Approach 1:
The patent merges two thin film transistors into a stacked configuration where they share a common active layer. The first TFT (bottom-gate) and second TFT (top-gate) are vertically stacked and share the same active layer, significantly reducing the horizontal area occupied by these transistors while maintaining their individual switching functions required for the GOA circuit.
Solution Approach 2:
The patent transitions from a planar arrangement of transistors to a three-dimensional stacked structure. By stacking the first TFT and second TFT vertically with shared active layer, the design moves the solution into the vertical dimension, reducing the footprint area while preserving the necessary transistor count and functionality for gate driver operation.
2Reliability
If multiple thin film transistors are formed in the GOA circuit, then the scanning driver function is achieved, but the border width of the display panel increases
Solution Approach 1:
The stacked TFT structure merges two transistors into a compact vertical arrangement, reducing the horizontal space required for the GOA circuit. This directly reduces the border width of the display panel while maintaining the scanning driver function, enabling narrower bezel designs.
3Reliability
If multiple thin film transistors are formed in the GOA circuit, then the circuit functionality is achieved, but the aperture ratio of the display panel decreases
Solution Approach 1:
By merging two transistors into a stacked configuration that shares a common active layer, the patent reduces the total area occupied by transistor structures. This increases the aperture ratio (the ratio of display area to total panel area) while maintaining full circuit functionality for the GOA scanning driver.
Solution Approach 2:
The vertical stacking of transistors moves the circuit elements into the third dimension, freeing up horizontal space that can be converted to display area. This dimensional transition directly improves the aperture ratio while preserving all necessary circuit functions.
Data Source
AI summary
A thin film transistor structure and a manufacturing method thereof, a circuit structure, a display substrate and a display device are provided. The thin film transistor structure includes: a base plate, and a first thin film transistor and a second thin film transistor stacked on the base plate. The first thin film transistor and the second thin film transistor share a same active layer.