Micro LED Array Substrate With Graphene TFT Integration
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Solution Overview
Problem
Current micro LED display manufacturing processes face challenges in efficiently integrating micro light emitting diodes (micro LEDs) with thin film transistors on a substrate, particularly in achieving stable and efficient electrical connections while maintaining high luminous efficiency and long lifespan.
Innovation Solution
The integration of a micro LED array substrate with a thin film transistor, where the first buffer layer and active layer are made from graphene, and the second buffer layer is from materials like gallium nitride, indium phosphide, or aluminum gallium arsenide, with specific electrode configurations and contact vias to ensure efficient electrical connectivity and common electrode voltage application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If micro LEDs are formed on monocrystalline silicon substrate and then diced to obtain individual micro LEDs for transfer to array substrate, then the luminous efficiency and brightness are improved, but the manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent merges the micro LED formation process with the array substrate manufacturing process by directly forming micro LEDs on the array substrate itself, eliminating the need for separate monocrystalline silicon substrate, dicing, and transfer operations. This integration maintains high luminous efficiency while significantly reducing manufacturing complexity.
Solution Approach 2:
The patent segments the manufacturing process into direct formation steps on the array substrate, avoiding the need to complete the entire micro LED structure on a separate substrate before transfer. This allows for simplified processing while maintaining the benefits of micro LED technology.
2Device complexity
If thin film transistors and micro LEDs are integrated on the same array substrate, then the manufacturing process is simplified and costs are reduced, but achieving stable electrical connections becomes more challenging
Solution Approach 1:
The patent performs preliminary actions by forming the buffer layer and active layer simultaneously in the same process step, ensuring proper material alignment and electrical connection pathways are established before subsequent processing steps. This preliminary coordination ensures stable electrical connections while maintaining manufacturing simplicity.
Solution Approach 2:
The patent applies local quality by using graphene specifically for the buffer and active layers where electrical connection stability is critical, while other parts of the device can use different materials optimized for their specific functions. This localized material selection ensures reliable electrical connections without complicating the overall manufacturing process.
3Ease of manufacture
If graphene is used for both buffer layer and active layer, then the manufacturing process is simplified with same-material processing, but the crystal structure matching with subsequent layers becomes critical
Solution Approach 1:
The patent changes the crystal structure parameter of the graphene layers by controlling their orientation and stacking, ensuring compatibility with subsequent semiconductor layers. This parameter adjustment allows for simplified same-material processing while maintaining the precise crystal structure matching required for device performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach simplifies the manufacturing process, reduces costs, and enhances the stability and luminous efficiency of micro LEDs, enabling a more efficient and cost-effective display device with improved performance.
Implementation Method 1
The material of the first buffer layer and the active layer comprises graphene
Implementation Method 2
a micro light emitting diode (micro LED) is a light emitting device using an inorganic material, such as gallium nitride, as a luminescent material
Implementation Method 3
a micro light emitting diode (micro LED) is a light emitting device using an inorganic material, such as gallium nitride, as a luminescent material
Data Source
Figure 1~2B
Figure 2C~3A
Figure 3B~4
AI summary
An array substrate includes a base substrate; a thin film transistor on the base substrate, including a gate electrode connected to a gate line, an active layer, a gate insulating layer insulating the gate electrode from the active layer, a first electrode connected to a data line, and a second electrode spaced apart from the first electrode; and a micro light emitting diode on the base substrate, including a first electrode, a first buffer layer, a light emitting layer, and a second electrode, which are stacked on top of each other. The first buffer layer is in a same layer as the active layer. The second electrode of the thin film transistor is connected to one of the first electrode of the micro light emitting diode or the second electrode of the micro light emitting diode.