Spacer Pattern Formation in OLED Display Substrates
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Solution Overview
Problem
The existing methods for preparing a spacer pattern in OLED display substrates result in uneven brightness and image display instability due to excessive ultraviolet exposure affecting the Thin Film Transistors (TFTs), as the organic resin spacer material requires high exposure energy, leading to varying threshold voltages across TFTs.
Innovation Solution
A method involving the formation of a photoresist pattern with a hollow region on a base substrate with TFTs, followed by coating a spacer material and baking it, then peeling the photoresist to create the spacer pattern, which reduces the required ultraviolet exposure energy and minimizes light reaching the active layer of the TFTs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a spacer material is coated on a base substrate with a pixel defining layer and exposed under ultraviolet light using a mask to form a spacer pattern, then the spacer pattern can be formed, but the exposure energy required is large which causes the threshold voltages of TFTs to drift and affects image display stability
Solution Approach 1:
The invention divides the base substrate into two regions: a first region with TFTs that is not exposed to ultraviolet light, and a second region without TFTs that is exposed to form the spacer pattern. This spatial segmentation allows the spacer pattern to be formed only where needed, preventing ultraviolet light from reaching and affecting the TFTs in the first region, thereby resolving the contradiction between forming the spacer pattern and maintaining TFT threshold voltage stability.
2Length of stationary object
If the spacer layer thickness is large to ensure proper spacer function, then the spacer can effectively define pixel boundaries, but the area to be exposed is large requiring high exposure energy that affects TFT characteristics
Solution Approach 1:
The invention segments the exposure area to only the second region where no TFTs are present. This allows the spacer layer to maintain its necessary thickness for proper pixel boundary definition while limiting ultraviolet exposure to areas without sensitive TFTs, thereby reducing the harmful energy exposure without compromising spacer functionality.
3Manufacturing precision
If ultraviolet light is used to expose the spacer layer for pattern formation, then the spacer pattern can be created, but the light reaches the active layer in TFTs causing threshold voltage drift and uneven pixel brightness
Solution Approach 1:
The base substrate is divided into a first region containing TFTs that is shielded from ultraviolet light and a second region without TFTs that receives ultraviolet exposure for spacer pattern formation. This segmentation eliminates the harmful interaction between ultraviolet light and TFTs while maintaining the ability to form precise spacer patterns in the second region.
Solution Approach 2:
The invention applies different treatment to different regions: the first region with TFTs receives no ultraviolet exposure to protect sensitive characteristics, while the second region receives full exposure to form the spacer pattern. This local differentiation allows the spacer pattern to be formed with high precision without exposing TFTs to harmful ultraviolet light.
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 ensures the stability of the display substrate by reducing ultraviolet light exposure to the TFTs, resulting in consistent pixel brightness and improved image display stability.
Implementation Method 1
exposing the base substrate coated with the spacer layer under ultraviolet light using a mask to form a spacer pattern
Implementation Method 2
baking the spacer material at a predetermined temperature
Data Source
AI summary
The present disclosure discloses a method for fabricating a display substrate, belonging to the technical field of displaying. The method includes: providing a base substrate having an array of Thin Film Transistors; forming a photoresist pattern on the base substrate, the photoresist pattern including a hollow region for forming a spacer pattern; forming a spacer material in the hollow region; and peeling the photoresist pattern so that the spacer material in the hollow region forms the spacer pattern.