Metal OLED Deposition Mask Layout for Uniform Pixel Patterning
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Solution Overview
Problem
Existing deposition masks with elliptical-shaped through-holes in a zigzag form suffer from non-uniformity in through-hole sizes and island sizes, leading to variations in deposition patterns.
Innovation Solution
A deposition mask with a metal plate design featuring alternating large and small surface holes connected by communication portions with different diameters, inclined at specific angles, and island portions with controlled size deviations, ensuring uniformity across different directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If elliptical-shaped through-holes are disposed in a zigzag form to improve deposition pattern coverage, then the deposition area is increased, but the uniformity of through-hole sizes and island sizes deteriorates
Solution Approach 1:
The patent applies local quality by making the communication portions have different shapes in different regions of the deposition mask. Specifically, communication portions are classified into first types and second types based on their orientations, with each type having specific elliptical shape characteristics (first diameter and second diameter ratios). This local differentiation allows the mask to achieve both increased deposition area through zigzag arrangement and maintained uniformity by optimizing each region's specific geometry
Solution Approach 2:
The patent utilizes parameter changes by systematically varying the elliptical shape parameters (first diameter and second diameter) of communication portions based on their position and orientation. The first diameter is set to be larger than the second diameter, and the ratio between them is controlled within specific ranges (0.7-0.95) to optimize deposition uniformity while maintaining the zigzag pattern's area expansion benefits
2Manufacturing precision
If the communication portion has an elliptical shape with different first and second diameters to control deposition direction, then deposition anisotropy is reduced, but the structural complexity of the through-hole increases
Solution Approach 1:
The patent deliberately introduces asymmetry by designing communication portions with elliptical shapes where the first diameter is larger than the second diameter. This asymmetric geometry is strategically oriented at specific angles (30-60 degrees or 120-150 degrees relative to the longitudinal axis) to compensate for deposition anisotropy. The asymmetric design, while increasing structural complexity, provides precise control over deposition patterns and improves uniformity across different directions
Solution Approach 2:
The patent transitions from simple circular holes to three-dimensional elliptical communication portions with controlled orientation angles. By introducing angular orientation as an additional dimensional parameter, the system gains the ability to control deposition direction and compensate for anisotropy. The elliptical shape with specific orientation angles adds a rotational dimension to the hole geometry, enabling precise directional control
Data Source
AI summary
A deposition mask according to an embodiment comprises a metal plate comprising a deposition area and a non-deposition area. The through-hole comprises a communicating portion connected to a first facing hole configured such that the first diameter slopes at an acute angle with regard to one surface in the transverse-axis direction of the metal plate, and a communicating portion connected to a second facing hole configured such that the first diameter slopes at an obtuse angle with regard to one surface in the transverse-axis direction of the deposition mask. In the longitudinal-axis direction of the metal plate, the first facing hole and the second facing hole are arranged alternately in a row. In the transverse-axis direction of the metal plate, the first facing hole and the second facing hole are arranged alternately in a row. A first island portion is arranged between two adjacent first facing holes in a first diagonal direction joining the first diameters of the communicating portions connected to the first facing holes. A second island portion is arranged between two adjacent second facing holes in a second diagonal direction joining the first diameters of the communicating portions connected to the second facing holes. A rib is arranged between the first island portion and the second island portion. The deviation in size between the first island portion and the second island portion, which are adjacent to each other, is 30% or less.