OLED Spacer Prevents Donor Film Shift During LITI Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The laser-induced thermal imaging (LITI) method for fabricating OLED displays faces issues with the donor film shifting during vacuum bonding, leading to defective pixels due to organic material not being transferred correctly to the light emitting region.
Innovation Solution
The OLED display design includes a spacer within the boundary line of the storage capacitor, which is formed to have the same thickness as the pixel definition layer, and an encapsulation substrate to minimize the non-transfer region during the LITI process, ensuring accurate transfer of the organic emission layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the LITI method is used to form organic light emitting layers, then fine patterning of emission layers can be achieved, but the donor film may shift in position during vacuum bonding causing defective pixels
Solution Approach 1:
The spacer is formed in advance before the LITI process to create a physical barrier that prevents donor film shift during vacuum bonding. This preliminary structural preparation ensures that the donor film remains in its correct position throughout the bonding process, thereby preventing pixel defects while maintaining patterning precision
Solution Approach 2:
The spacer acts as an intermediary element between the pixel definition layer and the encapsulation substrate. It provides a mechanical barrier that mediates the interaction between the donor film and the underlying structure during bonding, preventing direct contact that would cause the donor film to shift and creating defective pixels
2Ease of manufacture
If the donor film is bonded to the substrate during vacuum bonding, then the organic emission layer can be transferred, but the organic material may shift and not remain on the donor film
Solution Approach 1:
The spacer is positioned to preemptively counteract the shifting force that occurs during vacuum bonding. By creating a physical barrier before the bonding process begins, it prevents the organic material from shifting off the donor film, thereby maintaining material position accuracy while still allowing the transfer process to proceed
3Manufacturing precision
If the spacer is positioned at the opening, then the organic emission layer position is maintained, but the spacer may overlap the storage capacitor
Solution Approach 1:
The spacer is designed with specific local properties - it is positioned to overlap the storage capacitor in a controlled manner, creating a localized barrier only where needed to prevent donor film shift. This localized approach maintains emission layer positioning precision while minimizing the impact on overall device complexity and capacitor layout
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 reduces the likelihood of pixel defects by maintaining the organic emission layer's position and integrity, enhancing the overall quality of the OLED display.
Implementation Method 1
a laser beam is irradiated through a mask pattern on a donor film. The donor film is formed of a base film and transfer layer. When irradiated, the mask pattern is transferred through the transfer layer to form a light emission layer.
Data Source
AI summary
An organic light emitting diode display includes a first transistor on a substrate, a first electrode connected to the first transistor, and a pixel definition layer on the first electrode. The pixel definition layer has an opening exposing the first electrode. A spacer is formed at the opening. An organic emission layer is on the exposed first electrode, and a second electrode on the organic emission layer.