OLED Pixel Definition Layers Inkjet Printing
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Solution Overview
Problem
Conventional OLED display panels face issues with color miscibility between adjacent pixel units and low luminous efficiency of blue sub-pixels, limiting the mass production of ink-jet printed OLEDs due to high manufacturing costs and accuracy limitations.
Innovation Solution
The display panel incorporates pixel units with first and second pixel definition layers, where each pixel unit includes red, green, and blue sub-pixels, with the second pixel definition layer separating sub-pixels and the first pixel definition layers enclosing them, enhancing separation and luminous efficiency through varying sub-pixel areas and shapes, and using ink-jet printing for manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ink-jet printing is used to manufacture OLED displays, then manufacturing cost is reduced and material utilization is improved, but color miscibility occurs between adjacent pixel units due to solution process and printing accuracy limitations
Solution Approach 1:
The patent divides each pixel unit into multiple isolated grooves, with each groove containing a single sub-pixel (red, green, or blue). This segmentation prevents color miscibility between adjacent pixel units while maintaining the cost advantages of ink-jet printing. The grooves act as physical barriers that isolate the inkjet-deposited materials during the solution process.
Solution Approach 2:
The patent applies different groove dimensions and depths to different pixel regions. Specifically, grooves containing blue sub-pixels have different characteristics compared to those containing red or green sub-pixels, optimizing the local quality for each color's luminous efficiency requirements while preventing cross-contamination.
2Reliability
If conventional vacuum thermal evaporation process is used, then OLED functional layers are formed with good quality, but manufacturing cost is high limiting large-scale commercialization
Solution Approach 1:
The patent replaces the vacuum thermal evaporation process with ink-jet printing technology. This substitution eliminates the need for expensive vacuum equipment and materials while achieving comparable or superior functional layer quality through precise digital deposition control. The ink-jet process deposits organic materials directly in solution form, which is then cured to form the desired functional layers.
3Productivity
If blue sub-pixel area is kept small to fit more pixels, then pixel density is improved, but luminous efficiency of blue sub-pixels decreases
Solution Approach 1:
The patent changes the groove depth parameter for blue sub-pixel grooves compared to red and green sub-pixel grooves. The increased groove depth for blue sub-pixels allows for greater inkjet material deposition volume within the same surface area, thereby improving luminous efficiency without increasing the projected pixel area and maintaining high pixel density.
Data Source
AI summary
A display panel and a method for manufacturing the display panel are provided. The display panel includes a plurality of pixel units, wherein each of the pixel units includes first sub-pixels, second sub-pixels, third sub-pixels, first pixel definition layers, and a second pixel definition layer. Each of the pixel units is enclosed by one of the first pixel definition layers into a rectangle; and the second pixel definition layer is disposed in each of the first pixel definition layers and between the first sub-pixels, the second sub-pixels, and the third sub-pixels.