OLED Fabrication Using Exfoliation Layer for Mask Alignment
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Solution Overview
Problem
High-resolution organic light emitting diode displays face challenges in achieving accurate alignment of mask openings with pixel regions, leading to color mixing and reduced resolution due to the high cost and limited production capacity of fine-metal-mask (FMM) technology, which requires strict thickness control and is prone to inaccuracies in tensioning processes.
Innovation Solution
A method involving the formation of a pixel definition layer with predetermined areas on a base substrate, where an exfoliation layer made of sulfur is used, and an organic light emitting layer is formed using masks with openings greater than the default value, allowing for the peeling off of the exfoliation layer and organic light emitting layer during heating to create light emitting units, thereby improving alignment and reducing the reliance on FMMs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fine-metal-mask (FMM) is used to coat light emitting materials for high resolution, then the screen resolution is improved, but the production cost and manufacturing complexity increase significantly
Solution Approach 1:
The pixel definition layer is divided into multiple pixel definition units with predetermined areas, allowing selective formation of light emitting units in specific regions without requiring a complete fine-metal-mask for the entire substrate, thereby reducing manufacturing complexity while maintaining high resolution in targeted areas
Solution Approach 2:
The pixel definition layer is formed in advance with predetermined areas defined before the light emitting material coating process, enabling subsequent selective deposition without requiring complex real-time mask alignment, thus reducing production complexity while achieving high resolution
2Object-affected harmful factors
If the FMM thickness is strictly controlled to reduce shadow, then the mask shadow is reduced, but the alignment accuracy between mask openings and pixel regions deteriorates
Solution Approach 1:
The pixel definition layer acts as an intermediary structure that defines predetermined areas before material deposition. This intermediary layer eliminates the need for ultra-thin FMM by providing a robust physical guide for selective coating, thereby reducing mask shadow while maintaining alignment accuracy through the defined pixel regions
Solution Approach 2:
The mechanical alignment system (thin FMM requiring precise tensioning) is replaced with a pattern-based system where the pixel definition layer's predetermined areas guide material deposition. This substitution eliminates the trade-off between thickness and alignment by using a thicker, more stable pixel definition layer instead of a ultra-thin mask
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 enhances the resolution of organic light emitting diode displays by preventing color mixing and reducing production costs by allowing for accurate mask alignment and reducing the need for high-resolution FMMs, while improving production efficiency.
Implementation Method 1
heating the base substrate to cause sublimation of the material of the exfoliation layer, thereby peeling off the exfoliation layer and the organic light emitting layer attached to the exfoliation layer
Implementation Method 2
coating by evaporating a material to be peeled off on the base substrate corresponding to two of the first predetermined area, the second predetermined area, and the third predetermined area to form the exfoliation layer
Data Source
AI summary
The present invention provides a method of fabricating an organic light emitting diode display, including forming an exfoliation layer to be peeled off on the base substrate corresponding to two of the first predetermined area, the second predetermined area, and the third predetermined area; using a predetermined mask to form an organic light emitting layer on the exfoliation layer and the base substrate which is not covered by the exfoliation layer; and heating the base substrate to peel off the exfoliation layer and the organic light emitting layer on the exfoliation layer, while remaining the organic light emitting layer not covered by the exfoliation layer.