Mask Frame Assembly for OLED Deposition
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Solution Overview
Problem
Conventional mask frame assemblies for depositing thin films in organic electroluminescent devices face issues with robustness and maintaining desired gaps between unit pattern masks, leading to potential distortion and errors in electrode patterns due to uneven tensile forces.
Innovation Solution
A mask assembly with an open mask and unit pattern masks, where both ends of each unit pattern mask are fixed to the open mask in a specific direction, allowing for precise alignment and stability through elongated slots and ribs, maintaining consistent gaps between masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional mask is fixed onto a frame using tensile forces, then the mask can be secured in place, but the supporting bars of the frame curve and the openings become distorted
Solution Approach 1:
The mask is divided into multiple unit pattern masks, each independently fixed to the frame. This segmentation reduces the overall tensile force required for fixation and prevents distortion of individual openings, as each unit can be secured with minimal stress.
Solution Approach 2:
A rib structure is introduced as an intermediary element between the frame and the unit pattern masks. The ribs provide additional support and distribute the tensile forces evenly, preventing curvature of the supporting bars and distortion of the openings while maintaining secure fixation.
2Stability of the object's composition
If tensile force is applied to prevent mask drooping, then the mask remains stable, but the frame supporting bars curve and openings distort
Solution Approach 1:
Dividing the mask into multiple unit pattern masks reduces the tensile force required for each individual unit, thereby maintaining mask stability while preventing opening distortion. Each segmented unit can be fixed with minimal stress, preserving its geometric integrity.
Solution Approach 2:
The rib structure serves as a pre-designed support element that cushions and distributes the tensile forces before they can cause distortion. By incorporating these ribs in advance, the system prevents both mask drooping and opening distortion simultaneously.
3Manufacturing precision
If unit pattern masks are welded onto the frame, then opening transformation is prevented, but robustness and gap maintenance remain problematic
Solution Approach 1:
The rib structure acts as an intermediary that provides mechanical support and maintains precise gaps between unit pattern masks without requiring welding. This intermediate support structure enhances assembly robustness while preserving opening precision through distributed force support.
Data Source
AI summary
A mask assembly configured to prevent the mask from being thermally transformed and to maintain gaps between a plurality of divided pattern masks is disclosed. According to one embodiment, the mask assembly comprises: an open mask that has a plurality of first openings arranged in rows and columns; and a pattern mask that comprises a plurality of unit pattern masks. In some embodiments, the ends of the unit pattern masks may be fixed with respect to the open mask, and the unit pattern mask includes a plurality of mask pattern units configured to align with the plurality of first openings of the open mask. In some embodiments, a tensile force is applied to the unit pattern mask(s).