OLED Evaporation Mask with Segmented Regions for Uniform Thickness
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Solution Overview
Problem
Current OLED display panel manufacturing masks result in non-uniform organic material layer thickness, leading to darkening in luminance at the left and right sides of the panel, reducing yield.
Innovation Solution
A mask design with graphic and covering mask layers, including effective, ineffective, and marginal regions with pixel shaping openings, and a supporting mask layer, which ensures uniform etching and magnetic force distribution during evaporation, preventing organic material deposition in undesired areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional mask design is used, then the manufacturing process is simple, but the organic material layer thickness becomes non-uniform causing luminance darkening
Solution Approach 1:
The mask is divided into multiple functional regions: effective region with pixel shaping openings for pattern formation, marginal region with pixel shaping openings for uniform etching and magnetic force distribution, and ineffective region covered by covering mask blocks to prevent unwanted deposition. This segmentation allows each region to perform its specific function, achieving uniform organic material layer thickness while maintaining manageable complexity through modular design
Solution Approach 2:
Different regions of the mask are assigned different properties: the effective region contains the actual pixel patterns, the marginal region contains pixel shaping openings to ensure uniform evaporation angles and magnetic force distribution at edges, and the ineffective region is covered to prevent material deposition. This local differentiation optimizes the overall evaporation process uniformity across the substrate
2Manufacturing precision
If the mask has more regions with pixel shaping openings, then etching uniformity improves, but the mask manufacturing complexity increases
Solution Approach 1:
The mask is divided into effective, marginal, and ineffective regions, each with pixel shaping openings serving specific purposes. The marginal region's openings are specifically designed to ensure uniform etching and magnetic force distribution, improving overall etching uniformity while keeping the design modular and manageable through clear functional segmentation
3Manufacturing precision
If the covering mask block covers pixel shaping openings in ineffective regions, then organic material deposition accuracy improves, but the mask structure becomes more complex
Solution Approach 1:
The mask is segmented into graphic mask blocks and covering mask blocks, where covering mask blocks specifically cover the ineffective regions to prevent unwanted organic material deposition. This segmentation achieves precise deposition control by clearly separating functional regions
Solution Approach 2:
The covering mask blocks are placed specifically in ineffective regions where pixel shaping openings would otherwise cause unwanted deposition. This local application of covering blocks provides precise deposition control only where needed, maintaining simplicity in regions where it is not 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
The solution achieves uniform organic material layer thickness and improved yield by ensuring uniform evaporation angles and magnetic force distributions, mitigating luminance darkening issues.
Implementation Method 1
in the process of evaporating organic material, magnetic force distributions at the edge and the inside of the effective region become more uniform
Implementation Method 2
OLED light emitting devices are manufactured by evaporating organic material onto a substrate
Implementation Method 3
The evaporation of organic material usually requires the use of a mask such as a fine metal mask (FMM)
Data Source
AI summary
A mask includes a graphic mask layer having a plurality of graphic mask blocks mutually spaced apart and arranged in parallel, and a covering mask layer having a plurality of covering mask blocks mutually spaced apart and arranged in parallel. The covering mask block covers a gap between adjacent graphic mask blocks. The graphic mask block includes an effective region, an ineffective region, and a marginal region between the effective region and the ineffective region, wherein each region has a plurality of pixel shaping openings, and the covering mask block further covers the pixel shaping openings of the ineffective regions of the adjacent graphic mask blocks. The motherboard is used for manufacturing the mask. The device for manufacturing mask comprises the motherboard, a base table, a stretcher and a welding machine. The system for evaporating the display substrate includes an evaporator and the mask.