Display Pixel Layout Separating Transistor and Light-Emitting Element
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Solution Overview
Problem
Current display devices face challenges in simplifying the fabrication process while integrating light-emitting elements and transistors effectively, particularly in ensuring the active material layer does not overlap with the light-emitting elements in the thickness direction to maintain efficient light emission.
Innovation Solution
A display device design that includes a substrate with emission and non-emission areas, specific electrode configurations, and an active material layer made of oxide semiconductor, where the transistor is formed above the light-emitting element, and contact electrodes are integrated with the active material layer, reducing the number of fabrication processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the transistor is formed above the light-emitting element, then the fabrication process is simplified, but the active material layer may overlap with the light-emitting element in the thickness direction, potentially blocking light emission
Solution Approach 1:
The patent positions the transistor and light-emitting element side-by-side in the planar dimension rather than stacking them vertically. The transistor is formed in a non-emission area adjacent to the light-emitting element, eliminating thickness-direction overlap while maintaining fabrication efficiency through integrated process steps.
Solution Approach 2:
The substrate is divided into distinct emission and non-emission areas, with the light-emitting element positioned in the emission area and the transistor positioned in the non-emission area. This spatial segmentation allows both components to coexist without interference, enabling simplified fabrication while preserving light emission pathways.
2Illumination intensity
If the active material layer is positioned to avoid overlapping the light-emitting element, then light emission efficiency is maintained, but the device structure becomes more complex
Solution Approach 1:
The same fabrication process steps are used to form both the light-emitting element and the transistor, including the formation of the active material layer, electrodes, and insulating layers. This multi-functional approach achieves non-overlapping positioning without requiring additional complex processing steps.
Solution Approach 2:
The transistor and light-emitting element are integrated into a single device structure on the same substrate, sharing common fabrication processes and material layers. The active material layer serves both as the transistor channel and as a contact layer for the light-emitting element, eliminating the need for separate structures.
3Productivity
If contact electrodes are integrated with the active material layer at the same layer, then the number of fabrication processes is reduced, but electrical connection reliability may be compromised
Solution Approach 1:
The contact electrode and active material layer are formed as a composite structure using the same oxide semiconductor material with different doping levels or thicknesses. This integrated composite structure ensures reliable electrical connection while being formed in a single fabrication process step.
Solution Approach 2:
The electrical connection reliability is maintained by adjusting material parameters such as doping concentration, layer thickness, or crystallinity of the oxide semiconductor in the contact electrode region compared to the active material layer, allowing both components to be formed in the same process while ensuring proper electrical performance.
Data Source
AI summary
A display device includes a substrate having an emission area and a non-emission area, a first electrode and a second electrode spaced from each other on the substrate in the emission area, a first insulating layer on the substrate in the emission area and the non-emission area and covering at least a portion of the first electrode and the second electrode, a light-emitting element between the first electrode and the second electrode, a first contact electrode on the first electrode and in contact with one end portion of the light-emitting element, and a second contact electrode on the second electrode and in contact with the other end portion of the light-emitting element, a first active material layer on the first insulating layer in the non-emission area and electrically connected to the first contact electrode, and a gate insulating layer on the first active material layer.