Mask-Support Assembly for OLED Pixel Deposition
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Solution Overview
Problem
Conventional OLED manufacturing processes face challenges in aligning and stabilizing large-area masks due to sagging or twisting, which can lead to pixel deposition failures, especially in ultra-high-resolution applications like microdisplays for virtual reality devices, where precise alignment and uniform stress distribution are critical.
Innovation Solution
A mask-support assembly with a support structure featuring an edge portion and grid portions, connected to a mask with cell portions, separation portions, and an outer peripheral portion, made from materials like Ni, Cu, Ti, and Invar, ensuring clear alignment and uniform stress distribution, and a producing method involving electroforming and heat treatment to prevent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large-area mask is used for OLED pixel deposition, then the deposition area is sufficient, but the mask sags or twists due to its thin film structure and large area
Solution Approach 1:
The support structure is divided into multiple grid portions that extend in both horizontal and vertical directions, creating a segmented framework. This segmentation provides distributed support points across the large-area mask, preventing sagging and twisting while maintaining overall mask integrity and flatness.
Solution Approach 2:
The support structure implements different structural characteristics at different locations: grid portions provide distributed support across the mask area, while edge portions provide reinforced boundary support. This local differentiation addresses the specific stability needs of different regions of the large-area mask.
2Manufacturing precision
If a thin mask film is used to achieve fine mask patterns, then the mask resolution is improved, but the mask becomes more prone to sagging and twisting
Solution Approach 1:
The invention uses a thin mask film (1-10 μm) to achieve fine mask patterns with high resolution. The mask film is made sufficiently thin to enable precise pattern formation while the support structure compensates for the reduced mechanical strength, allowing the thin film to maintain its shape and positioning accuracy.
Solution Approach 2:
The segmented grid support structure provides multiple localized support points that distribute the mechanical load across the thin mask film. This segmentation prevents stress concentration that would cause sagging or twisting, enabling the use of thin films for high-resolution patterns while maintaining structural integrity.
3Reliability
If the mask is welded and fixed to the frame, then the mask is secured in position, but the alignment precision is compromised
Solution Approach 1:
The mask is pre-aligned with the support structure before fixation. The support structure includes alignment features that guide the mask into precise positioning prior to welding or bonding. This preliminary alignment action ensures high alignment precision is achieved before the mask is permanently fixed to the frame.
4Area of stationary object
If the mask area is increased to cover the substrate, then the deposition coverage is improved, but the stress distribution becomes non-uniform causing deformation
Solution Approach 1:
The support structure is segmented into multiple grid portions that distribute mechanical stress uniformly across the entire large-area mask. This segmented framework prevents stress concentration in any single region, maintaining uniform stress distribution even as the mask area increases to provide full substrate coverage.
Solution Approach 2:
The grid support structure creates a mechanically equipotential surface by distributing support evenly across the mask area. This equipotential support system ensures uniform stress distribution throughout the large-area mask, preventing deformation while maintaining full substrate coverage for deposition.
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 solution enables stable and precise pixel deposition with clear alignment and uniform stress distribution, achieving ultra-high-resolution pixels of 2,000 PPI or higher, improving the reliability of microdisplay manufacturing by preventing mask distortion and ensuring accurate pixel formation.
Implementation Method 1
The support and the mask may be connected through a connection portion interposed therebetween, and the connection portion may include at least one of Ni, Cu, Ti, Au, Ag, Al, Sn, In, Bi, Zn, Sb, Ge, or Cd.
Implementation Method 2
a producing method involving electroforming and heat treatment to prevent deformation
Data Source
AI summary
The present invention relates to a mask-support assembly and a producing method thereof. The mask-support assembly according to the present invention may include: a support comprising an edge portion and a grid portion; and a mask connected onto the support and comprising a plurality of cell portions in each of which a mask pattern is formed, wherein at least a partial region of the support is exposed on one surface of the support except for a region where the cell portions of the mask are disposed.