Array Substrate Light-Shielding Block for OLED TFT Stability
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Solution Overview
Problem
In large-sized OLED display panels, the dense metal wires interfere with the stability of the thin film transistor (TFT) due to unblocked light reflection, compromising the TFT's characteristics.
Innovation Solution
An array substrate design featuring a light-shielding block with a first groove on the base substrate, a buffer layer with a second groove, and a channel layer in the second groove, where the light-shielding block can be made of nonmetal materials like black matrix or metal materials for effective light shielding, preventing light from reaching the channel layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a metal pattern is formed under the top-gate thin film transistor to protect channel layer stability, then the channel layer is protected from external light interference, but light reflected by other metal regions cannot be blocked and the thin film transistor stability is reduced
Solution Approach 1:
The light-shielding block is divided into two functional parts: a first light-shielding portion (metal pattern) that shields the channel layer from external light, and a second light-shielding portion (nonmetal material) that blocks reflected light from other metal regions. This segmentation allows each portion to address specific light interference problems without compromising TFT stability.
Solution Approach 2:
A nonmetal material light-shielding portion is introduced as an intermediary between the metal pattern and the channel layer. This intermediary blocks reflected light from other metal regions while allowing the metal pattern to continue providing protection from external light, thus resolving the contradiction between light shielding and TFT stability.
2Productivity
If metal wires are made dense in large-sized OLED display panel, then the display resolution is improved, but light reflection from metal regions interferes with thin film transistor characteristics
Solution Approach 1:
Different light-shielding materials are used in different locations: metal material is used where external light shielding is needed (under the channel layer), while nonmetal material is used where reflected light blocking is needed (adjacent to metal wires). This local differentiation allows high-density metal wiring for resolution while blocking reflected light interference through the nonmetal portions.
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 configuration enhances the stability of the TFT by blocking light reflections, preventing the double-TFT effect and improving the overall performance of the OLED display panel.
Implementation Method 1
a light-shielding block formed on the base substrate and provided with a first groove of which an opening direction is away from the base substrate
Data Source
AI summary
An array substrate, preparation method thereof, display panel and display device are provided. The array substrate includes a base substrate and a plurality of thin film transistors distributed on the base substrate in an array. Each thin film transistor includes: a light-shielding block formed on the base substrate and provided with a first groove of which an opening direction is away from the base substrate; a buffer layer formed on one side of the light-shielding block away from the base substrate, a region of the buffer layer corresponding to the first groove being disposed with a second groove of which an opening direction is away from the base substrate; and a channel layer formed in the second groove. The structure uses bulges on two sides of the first groove to shield the light rays in regions without the thin film transistor, thereby improving the stability of the thin film transistor.