Fine Metal Mask Design Simulation for OLED Wrinkle Reduction
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Solution Overview
Problem
The manufacturing of OLED display panels faces challenges with fine metal masks (FMMs) due to wrinkles and bending during the mesh stretching process, leading to displacement of vapor-deposited materials and color mixing, with current design predictions relying on experience resulting in high errors and low yield rates.
Innovation Solution
A design method involving the establishment of a three-dimensional simulation model of the FMM, acquisition of material property parameters, and simulation operations to predict deformation, stress, and strain conditions during mesh stretching, allowing for adjustment of design parameters to match preset results and reduce defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mesh stretching is performed on the etched FMM, then the FMM can be prepared for evaporation, but wrinkles and bending occur due to the thin and brittle structure
Solution Approach 1:
The patent applies preliminary action by performing mesh stretching on the FMM before the evaporation process. The stretching is done in advance to pre-position the mask and anticipate potential deformation, allowing for compensatory design adjustments to be made before actual use.
Solution Approach 2:
The patent employs parameter changes by modifying the material composition of the FMM, specifically using an Invar alloy with controlled nickel content (32-38%) to optimize the balance between brittleness and elasticity. This parameter adjustment allows the mask to withstand stretching while maintaining surface integrity.
2Productivity
If designers rely on experience to predict wrinkles and bending, then design decisions can be made quickly, but the prediction accuracy is low resulting in large errors
Solution Approach 1:
The patent replaces the mechanical/experiential prediction system with a computer simulation system. Finite element analysis and other computational methods are used to model and predict FMM deformation during stretching, substituting human experience with quantitative mechanical modeling for higher accuracy.
Solution Approach 2:
The patent creates virtual copies of the FMM through 3D simulation models that replicate the physical mask's geometry and material properties. These digital twins allow for virtual testing and prediction of deformation behavior without requiring physical prototypes or relying solely on designer experience.
3Manufacturing precision
If the FMM is made ultra-thin for high pixel density OLED, then vapor deposition precision is improved, but the FMM becomes more brittle and prone to wrinkles
Solution Approach 1:
The patent optimizes the material composition parameters of the FMM by controlling the nickel content in Invar alloy within a specific range (32-38%). This parameter optimization achieves the desired balance between maintaining ultra-thin dimensions for precision and ensuring sufficient mechanical strength to resist brittleness and wrinkle formation.
Solution Approach 2:
The patent uses Invar alloy, which is a composite material consisting primarily of iron and nickel with controlled composition. This composite structure provides both the thinness required for high pixel density applications and the mechanical strength needed to resist deformation during manufacturing processes.
Data Source
AI summary
In one embodiment, the design method for a fine metal mask includes: establishing a three-dimensional simulation model of the fine metal mask according to design parameters of the fine metal mask; acquiring material property parameters of the fine metal mask; performing a simulation operation on the three-dimensional simulation model according to the material property parameters and simulation conditions, in order to obtain a simulation result of the fine metal mask after a mesh stretching, and the simulation conditions are configured to represent constraint conditions of the fine metal mask during the mesh stretching, and the simulation result comprises at least one of a deformation condition, a stress condition and a strain condition of the fine metal mask after the mesh stretching is performed; determining whether the simulation result matches a preset result; adjusting the design parameters according to the simulation result if no, and selecting the design parameters if yes.