Segmented Mask Frame Assembly for OLED Pitch Control
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Solution Overview
Problem
Conventional mask frames for OLED device manufacturing suffer from sagging due to weight, deformation of pitch between strips due to tension, and variation of total pitch caused by internal stress, limiting the size and precision of the deposited patterns.
Innovation Solution
A mask frame assembly with at least two unit masks coupled to a frame, featuring deposition openings with a first gap between them, where the ends of the unit masks are bonded to the frame, allowing for precise control of pitch and reducing pattern deformation, using a magnetic thin film material like nickel or nickel-cobalt alloy for enhanced surface flatness and patterning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large mask is used to cover the entire substrate, then the substrate can be fully covered, but the mask sags due to its own weight
Solution Approach 1:
The mask is divided into multiple smaller unit masks arranged in an array, each covering a portion of the substrate. This segmentation reduces the weight and sagging of each individual mask while collectively covering the entire substrate area.
Solution Approach 2:
Multiple unit masks are arranged in a nested or array configuration within a frame structure, allowing each small mask to maintain flatness while the collective arrangement covers the large substrate area.
2Shape
If tension is applied to the mask to prevent sagging, then mask flatness is improved, but the pitch between slots deforms
Solution Approach 1:
By dividing the mask into multiple small unit masks, each unit can be independently supported by the frame without requiring high tension, thus preventing pitch deformation while maintaining flatness.
3Area of stationary object
If the mask size is increased to cover larger substrates, then substrate coverage is improved, but deformation due to weight increases
Solution Approach 1:
The large mask is segmented into multiple small unit masks, each maintaining precise pattern geometry while collectively covering the large substrate area, thereby preventing deformation.
Solution Approach 2:
The mask structure transitions from a single large 2D plane to an array of small units with 3D spacing control, allowing precise positioning and reduced deformation through the frame support structure.
4Device complexity
If a single large mask is used, then device complexity is reduced, but adherence to substrate deteriorates
Solution Approach 1:
The mask system is segmented into multiple small unit masks that can closely adhere to the substrate surface, improving reliability through better contact while maintaining manageable complexity through modular design.
Solution Approach 2:
Each unit mask is designed as a thin film structure that can flexibly adhere to the substrate surface, ensuring reliable contact and deposition while maintaining structural integrity.
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
Enables high precision pitch control between pixels, allowing for large-scale, high-quality OLED displays with reduced pattern deformation and improved adherence to the substrate, enhancing the manufacturing process for OLED devices.
Implementation Method 1
using a magnetic thin film material like nickel or nickel-cobalt alloy for enhanced surface flatness and patterning
Implementation Method 2
an organic light emitting layer, which may be formed by vacuum evaporation, on the substrate having the first electrode
Data Source
AI summary
A mask frame assembly for depositing a thin film including at least two unit masks, ends of the unit masks being coupled to a frame having an opening, and each unit mask includes a plurality of deposition openings. A first gap has a width substantially equal to a width of the deposition openings and is located between the unit masks.