OLED Mask Frame Deformation Prevention
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Solution Overview
Problem
In thin film deposition for OLEDs, mask deformation during attachment to a substrate leads to defects in image quality due to sagging and bending of deposition patterns, resulting in inadequate contact and reduced precision.
Innovation Solution
A mask frame assembly with a deformation prevention unit, featuring dummy patterns and half-etched portions on the mask, which are designed to minimize sagging and ensure precise attachment by distributing tensile forces evenly, thereby maintaining flatness and improving contact with the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the mask is made thin to reduce weight, then the weight of the mask is reduced, but the mask deforms during attachment due to sagging and bending
Solution Approach 1:
The patent changes the physical parameters of the mask by creating localized thickness variations through half-etched portions. These portions have reduced thickness compared to the main mask body, creating a gradient structure that redistributes stress and prevents uniform deformation while maintaining overall mask thinness and weight reduction.
Solution Approach 2:
The mask is segmented into regions of different thickness through the half-etched portions. This segmentation creates distinct functional zones: thinner regions for stress relief and deformation prevention, and thicker regions for maintaining structural integrity and pattern definition, resolving the contradiction between overall thinness and local stability.
2Manufacturing precision
If the mask is made thin to improve precision, then the manufacturing precision is improved, but the mask sags and bends during attachment
Solution Approach 1:
The patent modifies the thickness parameter locally through half-etched portions to prevent sagging and bending. This creates a non-uniform thickness profile that maintains mask flatness during attachment while preserving the thin overall structure necessary for high deposition precision and pattern accuracy.
Solution Approach 2:
The half-etched portions are pre-formed on the mask before attachment to counteract the expected sagging and bending forces. This preliminary structural modification creates built-in stress distribution that actively resists deformation during the attachment process, ensuring the mask maintains its shape for precise deposition.
3Shape
If dummy patterns are added to prevent deformation, then the mask flatness is improved, but the device complexity increases
Solution Approach 1:
Instead of adding complex dummy patterns, the patent modifies the existing mask structure by creating half-etched portions that change the thickness parameter. This approach achieves deformation prevention through geometric modification rather than adding separate components, thereby maintaining mask flatness while minimizing increases in device complexity.
Data Source
AI summary
A mask frame assembly for depositing a deposition material on a deposition substrate comprises a mask frame including an opening and frames surrounding the opening, and a mask coupled on the mask frame. A deformation prevention unit is formed on at least one region of the mask. Since the deformation prevention unit is formed on a peripheral portion of a deposition pattern in the mask, deformation of the mask in a vertical direction may be reduced. Accordingly, defective attaching of the mask to the substrate may be reduced.