Deposition Mask With Segmented Pattern Holes For OLED Uniformity
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Solution Overview
Problem
Existing deposition masks lack the necessary accuracy and uniformity in forming patterns on substrates during the deposition process for organic light emitting display devices, leading to inconsistencies in the thin film patterns formed.
Innovation Solution
A deposition mask design featuring a patterning region with varying pattern hole sizes and arrangements, including first, second, and third pattern portions, and blocking parts, where the minimum distance between adjacent pattern holes in the second and third portions is greater than in the first portion, and cutting parts with dummy pattern holes to enhance stability and alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a deposition mask with uniform pattern holes is used, then the mask structure is simple, but the deposition accuracy and uniformity are insufficient
Solution Approach 1:
The patent applies local quality by creating different pattern hole arrangements in different regions of the mask. The first pattern portion has holes spaced at a first distance, while the second pattern portion has holes spaced at a second distance that is greater than or equal to 20 μm. This regional differentiation improves deposition accuracy in specific areas without requiring complete redesign of the entire mask structure.
Solution Approach 2:
The mask pattern is segmented into multiple distinct portions: a first pattern portion with one spacing arrangement, a second pattern portion with a different spacing arrangement, and bonding regions. This segmentation allows each region to be optimized for its specific function, improving overall deposition precision while maintaining manageable structural complexity.
2Productivity
If pattern holes are closely spaced to increase deposition density, then productivity increases, but stress concentration at boundary regions increases
Solution Approach 1:
The patent addresses stress concentration by implementing local quality variations in the pattern hole spacing. The second pattern portion has increased spacing between holes compared to the first pattern portion, which reduces stress concentration at boundary regions while maintaining higher deposition density in the first pattern portion where it is most needed.
Solution Approach 2:
The design anticipates stress issues by pre-configuring the second pattern portion with larger spacing between holes. This beforehand cushioning approach prevents stress concentration before it occurs during the deposition process, thereby maintaining mask durability while still achieving high productivity in critical deposition areas.
3Manufacturing precision
If the mask structure is simplified for ease of manufacture, then manufacturing cost decreases, but deposition uniformity deteriorates
Solution Approach 1:
The patent achieves deposition uniformity through local quality variations rather than complete structural complexity. By modifying hole spacing only in specific regions (second pattern portion with ≥20 μm spacing) while keeping other regions simpler, the design improves uniformity without requiring complex manufacturing processes throughout the entire mask.
Solution Approach 2:
The patent applies partial action by implementing complex pattern arrangements only where necessary for deposition uniformity (in the second pattern portion), while leaving other regions with simpler structures. This selective approach achieves the required deposition uniformity without unnecessarily complicating the overall manufacturing process.
Data Source
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AI summary
Described is a deposition mask may include a patterning region provided with a pattern portion, and a plurality of bonding regions provided near opposite ends of the patterning region in a first direction. The pattern portion may include a first pattern portion, in which first pattern holes are defined, and a plurality of second pattern portions, in which second pattern holes are defined, and which are located between opposite ends of the first pattern portion and the bonding regions in the first direction. A minimum distance between adjacent ones of the second pattern holes may be larger than a minimum distance between adjacent ones of the first pattern holes.