OLED Deposition Mask Patterns for Residual Stress and Waviness
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Solution Overview
Problem
The deposition reliability of fine metal masks used in OLED manufacturing is compromised due to residual stress causing waviness and variations in the intervals between effective regions and through-holes, leading to reduced deposition accuracy and quality.
Innovation Solution
A deposition mask design featuring a metal plate with defined deposition and non-deposition regions, including patterns between effective regions to disperse residual stress, thereby reducing waviness and maintaining consistent intervals between through-holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the fine metal mask is stretched and connected to the frame to fix multiple masks, then the masks are securely positioned, but residual stress causes waviness and variations in intervals between effective regions and through-holes
Solution Approach 1:
The mask structure is divided into multiple independent masks (first mask, second mask, third mask, fourth mask) that can be separately positioned and fixed to the frame. Each mask is independently secured, allowing for precise positioning without the cumulative stress effects that would occur in a single continuous mask structure. This segmentation enables stable positioning while maintaining manufacturing precision.
2Productivity
If the fine metal mask is made with ultra-fine holes for RGB deposition, then color filter is not required and light efficiency is improved, but the process requires accurate alignment and is more difficult to manufacture
Solution Approach 1:
The deposition process is segmented into multiple steps using separate masks for different color layers. The first mask deposits the first color layer, the second mask deposits the second color layer, and so on. This segmentation of the deposition process allows each mask to have simpler hole patterns that are easier to manufacture with high precision, while still achieving the overall RGB color deposition goal.
Solution Approach 2:
Each color layer is prepared and deposited in separate preliminary steps using dedicated masks. The first color layer is fully deposited using the first mask before proceeding to the second color layer with the second mask. This preliminary action for each color layer simplifies the manufacturing process by breaking down the complex RGB deposition into manageable, sequentially executed steps with higher alignment accuracy.
3Reliability
If patterns are added to the non-effective region to disperse residual stress, then waviness is reduced and deposition reliability is improved, but the mask structure becomes more complex
Solution Approach 1:
Patterns are added specifically to the non-effective regions of the masks, which are areas that do not directly participate in the deposition process. These patterns serve to disperse residual stress and reduce waviness in the mask structure. By localizing the stress-dispersing patterns to non-effective regions rather than the entire mask, the solution improves deposition reliability while minimizing the increase in overall mask structure complexity.
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 proposed mask design enhances deposition reliability by minimizing variations in effective region intervals and through-hole positions, ensuring accurate and consistent deposition patterns on the substrate.
Implementation Method 1
The organic material is deposited on the deposition substrate using a deposition mask
Data Source
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AI summary
A deposition mask comprising; a metal plate including a deposition region and a non-deposition region, wherein the metal plate has a first direction, which is a longitudinal direction, and a second direction, which is a width direction, defined, wherein the deposition region includes a plurality of effective regions; and a non-effective region, wherein the non-effective region includes a first non-effective region between effective regions, wherein a plurality of through-holes is disposed in the effective region, wherein at least one pattern is disposed in the first non-effective region, wherein the pattern and the through-hole are formed in different shapes.