OLED Fabrication via Thermal Transfer for Pixel Thickness Control
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Solution Overview
Problem
Existing OLED manufacturing techniques result in varying optical thicknesses of R, G, and B pixels, leading to deteriorated color coordinates and efficiency characteristics in full-color OLED displays.
Innovation Solution
A method of fabricating OLEDs using a thermal transfer method to optimize the thicknesses of organic layers, specifically the hole injection, hole transport, emission, hole blocking, and electron transport layers for R, G, and B pixels, ensuring precise patterning and uniformity across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If prior art manufacturing techniques are used for full-color OLED, then the manufacturing process is simple, but the optical thicknesses of R, G and B pixels are different causing color coordinates and efficiency characteristics to deteriorate
Solution Approach 1:
The organic layer formation process is segmented into multiple stages: first forming a base organic layer across the entire substrate, then selectively adding additional organic material to specific pixel regions (R, G, B) to achieve the desired thickness variations. This segmentation allows precise control of optical thickness for each pixel type while maintaining a systematic manufacturing approach.
Solution Approach 2:
The patent applies local quality by creating different organic layer thicknesses in different spatial regions corresponding to R, G, and B pixels. The manufacturing process deposits additional organic material selectively on specific pixel areas to achieve the required optical thickness optimization for each color, rather than applying uniform thickness across the entire substrate.
2Reliability
If the organic layers are formed with different thicknesses for R, G and B pixels, then color coordinates improve, but the manufacturing precision becomes harder to control
Solution Approach 1:
The patent employs preliminary action by first forming a uniform base organic layer across the entire substrate before performing selective thickness adjustments. This preliminary step establishes a consistent foundation that simplifies subsequent precision control, as the selective addition process can focus on achieving specific thickness increments rather than controlling absolute thickness from scratch.
Solution Approach 2:
The patent replaces traditional mechanical masking and deposition methods with a self-aligned approach where the organic layer thickness is controlled through sequential deposition processes. The manufacturing system uses controlled material deposition rather than mechanical intervention to achieve precise thickness variations, improving both precision and reliability.
3Manufacturing precision
If a thermal transfer method is used to pattern organic layers, then thickness optimization for R, G and B pixels is achieved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent merges multiple functions into the thermal transfer process: pattern transfer, thickness control, and material deposition are combined in a single integrated step. The thermal transfer method simultaneously achieves precise patterning of the organic layers and controls the thickness distribution across different pixel regions, reducing the need for separate processing steps.
Solution Approach 2:
The patent uses a transfer layer as an intermediary element in the thermal transfer process. This intermediate layer carries the pattern information and thickness profile, which is then transferred to the organic layer during thermal processing. The intermediary enables precise thickness control without requiring direct mechanical manipulation of the organic material itself.
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 improves color coordinates and efficiency characteristics by optimizing the optical thicknesses of R, G, and B pixels, enhancing display quality and resolution in OLEDs.
Implementation Method 1
The remaining portion of the hole injection layer and the hole transport layer, and the emission layers of the R, G and B pixels, are simultaneously formed by a thermal transfer method using a thermal transfer device
Data Source
AI summary
A method of fabricating an organic light emitting display is capable of improving device characteristics by patterning a plurality of organic layers of an emission layer and a charge transport layer using a thermal transfer method to optimize thicknesses of the organic layers corresponding to R, G and B pixels. The method includes: forming lower electrodes of R, G and B pixels on a substrate; forming an organic layer on the layer; and forming an upper electrode on the organic layer. Formation of the organic layer includes forming a portion of a hole injection layer and a hole transport layer of the R, G and B pixels over an entire surface of the substrate, the organic layer comprising a first portion and a second portion, the organic layer having a thickness equal to a sum of the thicknesses of the hole injection layer and the hole transport layer. Formation of the organic layer further comprises patterning the second portion of the organic layer, and patterning emission layers of the R, G and B pixels. The second portion of the organic layer and the emission layers of the R, G and B pixels are simultaneously formed by a thermal transfer method using a thermal transfer device having the second portion of the organic layer and the emission layers of the R, G and B pixels as a transfer layer.