Organic EL Panel Mask Segmentation for Uniform Deposition
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Solution Overview
Problem
High-definition organic EL panel manufacturing faces challenges due to mask deformation under its own weight, leading to non-uniform deposition and reduced service life due to increased current density, as finer pixel pitches require thinner masks with smaller unopened regions, causing tension and deformation issues.
Innovation Solution
The use of two or more deposition masks with a checkerboard pattern arrangement, where openings correspond to every other or every few pixels, allowing for larger opening sizes and increased mask strength, enabling more uniform deposition and a larger light-emitting area, thereby extending the service life of the organic EL element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a thin mask is used for high-definition display manufacturing, then the pixel pitch can be reduced to achieve finer definition, but the mask deforms under its own weight causing non-uniform deposition
Solution Approach 1:
The mask is divided into multiple separate masks, each containing only a subset of the pixel openings. This segmentation allows each individual mask to have larger unopened regions (more mask material) providing sufficient structural strength, while collectively achieving complete pixel coverage. The mask structure is segmented both spatially (different masks for different pixel groups) and functionally (each mask handles specific color layers or pixel types).
2Manufacturing precision
If the unopened regions of the mask are made smaller to achieve finer pixel pitch, then higher definition is achieved, but the mask experiences larger tension and deformation
Solution Approach 1:
By segmenting the mask into multiple separate masks, each mask carries tension only over its own unopened regions, not the entire mask area. This distributes the mechanical stress and prevents excessive tension concentration that would cause deformation in a single comprehensive mask with fine pixel pitch.
3Strength
If the opening size is reduced to maintain sufficient unopened regions, then mask strength is improved, but the light-emitting area decreases requiring increased current density
Solution Approach 1:
Multiple masks work together to provide complete coverage, allowing each individual mask to have larger unopened regions for strength while the collective opening area across all masks maintains sufficient light-emitting area. This eliminates the need to reduce opening sizes in individual masks, avoiding the current density problem.
4Device complexity
If a single mask is used for deposition, then the process is simpler, but mask deformation prevents uniform deposition
Solution Approach 1:
The deposition process is segmented into multiple sequential steps, each using a different mask. While this increases process steps, each individual deposition step achieves high uniformity because the masks are thin enough to minimize deformation while still providing structural integrity through their segmented design.
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 ensures more uniform deposition and a larger light-emitting area, reducing deformation and extending the service life of the organic EL element while maintaining high-definition display capabilities.
Implementation Method 1
the organic material is vaporized from below so that the organic material will adhere to the first electrode exposed through the openings of the mask
Data Source
AI summary
A method of manufacturing a full-color organic EL panel in which pixels emitting light of different colors are formed by selectively depositing an organic material on a pixel-by-pixel basis, wherein, a deposition process of depositing an organic material for emitting light of at least one color includes a first step of depositing an organic material for emitting light of at least one color, using a first mask, on a first group of pixels corresponding to openings of the first mask, and a second step of depositing an organic material for emitting light of the same color as the one color, using a second mask, on a second group of the pixels corresponding to openings of the second mask.