OLED Function Layer Manufacturing via Coating and Inkjet Printing
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Solution Overview
Problem
Inkjet printing of hole injection and hole transport layers in OLED display panels requires a large number of inkjet heads for large-sized substrates, leading to calibration difficulties and swath mura issues at printing interfaces.
Innovation Solution
Combining entire-surface coating and inkjet printing techniques to form function layers, where a base thickness is achieved through coating and additional thickness is applied via inkjet printing in specific regions, reducing the number of inkjet heads and alleviating mura issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If inkjet printing is performed only once on a large-sized substrate, then the manufacturing process is simplified, but a great number of inkjet heads are needed which makes calibration difficult
Solution Approach 1:
The patent divides the substrate into multiple printing regions that can be processed by a smaller number of inkjet heads. By segmenting the printing area and using multiple printing passes with fewer heads, the system avoids the complexity of calibrating a large number of heads while still covering the entire large-sized substrate.
Solution Approach 2:
The patent applies preliminary coating to create a base layer before inkjet printing. This preliminary action ensures uniform thickness across the entire substrate, allowing subsequent inkjet printing to focus only on adding specific thickness in certain regions rather than printing the entire substrate from scratch, thereby reducing the number of inkjet heads needed.
2Device complexity
If inkjet printing is performed multiple times by using a small number of inkjet heads, then device complexity is reduced, but swath mura will occur at printing interfaces
Solution Approach 1:
The patent uses preliminary coating to create a uniform base layer before inkjet printing. This ensures that the substrate has consistent thickness and properties across all regions before printing begins, which helps prevent swath mura effects at printing interfaces during subsequent inkjet printing passes.
Solution Approach 2:
The patent employs different printing strategies for different regions of the substrate, adjusting printing parameters such as inkjet head position, printing speed, and material deposition amount based on the specific region being printed. This adaptive approach maintains uniformity at printing interfaces by compensating for potential swath mura effects.
3Manufacturing precision
If inkjet printing is used for the entire function layer, then manufacturing precision can be controlled, but a large number of inkjet heads are required for large-sized substrates
Solution Approach 1:
The patent segments the function layer manufacturing into two parts: a base layer created by preliminary coating and an additional thickness layer created by inkjet printing. This segmentation allows the use of fewer inkjet heads since they only need to deposit material in specific regions rather than covering the entire large-sized substrate.
Solution Approach 2:
The patent performs preliminary coating to create a uniform base layer with appropriate thickness before applying inkjet printing. This preliminary action ensures that the foundation layer has consistent properties across the entire substrate, allowing the inkjet printing process to focus on adding precise thickness variations only where needed, thereby reducing the number of inkjet heads required.
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 method allows for reduced inkjet heads usage and minimizes swath mura at printing interfaces, ensuring uniformity and efficiency in large-sized OLED display panel manufacturing.
Implementation Method 1
manufacturing by an entire-surface coating process a function layer having a first preset thickness between the anode layer and the light emitting layer
Implementation Method 2
manufacturing by an inkjet printing process a function layer having a second preset thickness in a first preset region of the function layer having the first preset thickness
Data Source
AI summary
An organic light emitting diode display panel, a manufacturing method thereof and a display device are disclosed, for reducing the number of inkjet heads used in inkjet printing or alleviating the swath mura at printing interfaces. The method comprises manufacturing an anode layer, a light emitting layer and a cathode layer on a base substrate, and the method can further comprise manufacturing by an entire-surface coating process a function layer having a first preset thickness between the anode layer and the light emitting layer; and in a first preset region of the function layer that has been manufactured, manufacturing by an inkjet printing process a function layer having a second preset thickness.