Mask Assembly Deposition Recesses for OLED Shadow Effects
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Solution Overview
Problem
Existing mask assemblies for organic light emitting diode displays face challenges in achieving uniform deposition quality due to shadow effects caused by insufficiently inclined sidewalls, leading to non-uniform thickness of organic emission layers.
Innovation Solution
A mask assembly with band-shaped unit masks featuring deposition openings and recesses, where the recesses are positioned to allow for sufficient inclination of sidewalls, ensuring uniform deposition by using the recesses as extended openings across subpixels, thereby reducing shadow effects and improving deposition quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional mask assemblies with flat openings are used, then the structure is simple, but shadow effects occur due to insufficiently inclined sidewalls, leading to non-uniform deposition quality
Solution Approach 1:
The mask assembly is divided into multiple band-shaped unit masks, each with specific deposition openings and recesses. This segmentation allows each unit mask to be independently designed with optimized sidewall inclination, eliminating shadow effects while maintaining overall structural manageability
Solution Approach 2:
Deposition recesses are added to create a three-dimensional structure with inclined sidewalls, transitioning from flat two-dimensional openings to multi-dimensional geometry. This dimensional change enables sufficient sidewall inclination to prevent shadow effects during deposition
2Reliability
If unit masks are fixed by tensile force to prevent hanging, then the mask maintains position, but the fixed structure may contribute to shadow effects
Solution Approach 1:
The mask is segmented into multiple unit masks that can be independently fixed to the frame. This allows precise positioning of each unit mask while maintaining the ability to create optimized deposition geometries with inclined sidewalls that prevent shadow effects
Solution Approach 2:
Different regions of the mask assembly have different structural characteristics - unit masks have flat openings for positioning, while deposition recesses have inclined sidewalls for uniform deposition. This local differentiation resolves the contradiction between positioning reliability and deposition uniformity
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 mask assembly enhances the deposition quality of organic emission layers by preventing shadow effects and ensuring uniform thickness, resulting in improved performance and quality of organic light emitting diode displays.
Implementation Method 1
The organic emission layer is formed by a deposition method using a mask assembly
Data Source
AI summary
A mask assembly includes a frame forming an opening, and a plurality of unit masks which form a plurality of deposition openings, the longitudinal ends of the unit masks being fixed to the frame. At least two adjacent ones of the plurality of unit masks have deposition recesses formed on both sides facing each other. The width of the deposition recesses along a width direction of the unit masks is equal to or greater than the width of the deposition openings along the width direction of the unit masks.