Shielding Layer Blocks Free Charges in Display Panel
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Solution Overview
Problem
Low-temperature polycrystalline oxide backplanes in display panels suffer from free charges that affect the electrical performance of transistors, leading to issues like image retention due to the influence of electric fields on threshold voltage, sub-threshold swing, and bias temperature stress.
Innovation Solution
A display panel design incorporating a substrate, a driving array, and a shielding layer, where the shielding layer is electrically connected to a stable voltage and positioned between the driving array and the substrate to block free charges, improving the electrical performance of transistors by allowing free charges to quickly move and disappear under the electric field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low-temperature polycrystalline oxide backplane is used, then charge mobility and stability are improved, but free charges affect transistor electrical performance causing image retention
Solution Approach 1:
A shielding layer is introduced as an intermediary component between the substrate and the driving array. This shielding layer acts as a mediator that blocks free charges from the substrate from directly interfering with the transistors in the driving array, while still allowing the beneficial electrical characteristics of the low-temperature polycrystalline oxide backplane to be maintained.
Solution Approach 2:
The harmful free charges are effectively extracted or removed from the path between the substrate and the transistors by placing the shielding layer in between. This separates the harmful factor (free charges) from the functional components (transistors), allowing the system to benefit from the oxide backplane without the negative effects of free charge interference.
2Reliability
If shielding layer is added to block free charges, then transistor electrical performance is improved, but device structure becomes more complex
Solution Approach 1:
The shielding layer is designed to serve multiple functions: it blocks free charges from interfering with transistors, provides a reference voltage for the backgate structure, and maintains electrical isolation between different components. By making this single component multi-functional, the overall device complexity increase is minimized while still achieving the desired improvement in transistor 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
The shielding layer effectively reduces the impact of free charges on transistor performance, enhancing the display effect by minimizing issues such as image retention.
Implementation Method 1
the free charge can quickly move and disappear with the back-channel effect under the action of the electric field
Data Source
AI summary
Provided are a display panel and a display device, comprising a substrate. A driving array on the substrate comprises a first active layer, a second active layer and a first metal layer stacked on the first active layer. An active pattern and a gate of the first transistor are respectively included in the first active layer and the first metal layer. An active pattern of the second transistor is included in the second active layer. A first shielding portion with a predetermined stable voltage is provided between the active pattern of the first transistor and the substrate.