Deposition Mask Sub-Mask Segmentation for Island-Like Holes
Solution Overview
Problem
The challenge in manufacturing organic light-emitting display devices is the exposure of organic layers to outside elements during the formation of penetration holes, which can lead to damage from air and moisture, and the difficulty in creating island-like masking surfaces using a single deposition mask.
Innovation Solution
A deposition mask with multiple sub-masks is used, where each sub-mask has an aperture and a masking surface with a hole-forming portion that is nested within the aperture, allowing for the formation of a deposition layer with an island-like hole, preventing exposure of the organic layer during subsequent laser processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single deposition mask is used to form an organic layer, then the manufacturing process is simple, but it is difficult to create an island-like masking surface with a hole
Solution Approach 1:
The deposition mask is divided into multiple sub-masks (first sub-mask, second sub-mask, third sub-mask) that can be selectively positioned and used. Each sub-mask has specific aperture patterns that, when combined through sequential deposition, create the complex island-like masking surface with a hole that cannot be achieved with a single mask design.
2Ease of manufacture
If penetration holes are formed by laser processing without pre-formed holes in organic layer, then the process is straightforward, but the organic layer is exposed to air and moisture causing damage
Solution Approach 1:
Holes are pre-formed in the organic layer during the deposition process itself, before the penetration hole formation step. The sub-masks are designed with hole-forming portions that create openings in the organic layer, which then serve as protected pathways for subsequent laser processing, preventing the organic layer from being exposed to damaging environmental factors.
3Manufacturing precision
If the aperture area is made small to define precise deposition regions, then the deposition precision is improved, but the total deposition area coverage is reduced
Solution Approach 1:
The total deposition area is segmented into multiple regions, each covered by specific sub-masks with appropriately sized apertures. The first sub-mask covers a first area, the second sub-mask covers a second area, and the third sub-mask covers a third area, collectively achieving complete area coverage while maintaining precise deposition control in each segmented region.
Solution Approach 2:
The solution transitions from a two-dimensional aperture design to a three-dimensional sequential deposition process. By using multiple sub-masks at different positions and deposition steps, the system achieves both precise local deposition control and complete overall area coverage, effectively adding a temporal/sequential dimension to the deposition process.
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
This method effectively prevents damage to the organic layer by forming a deposition layer with an island-like hole, ensuring the organic layer remains protected during the formation of penetration holes, thereby reducing exposure to outside elements and maintaining the integrity of the display device.
Implementation Method 1
a plurality of sub-masks 3a and 3b through which a deposition material passes to a base layer to form a deposition layer
Data Source
AI summary
A deposition mask includes: a plurality of sub-masks through which deposition material passes to a base layer to form a deposition layer defining a hole therein, each of the sub-masks including: an aperture through which the deposition material passes to the base layer, a total planar area of the aperture corresponding to less than a total planar area of the deposition layer, and a masking surface at which the deposition material does not pass through the sub-mask, the masking surface including a hole-forming portion of which a total planar area thereof corresponds to a total planar area of the hole defined in the deposition layer. The hole-forming portions of the sub-masks have a same shape and planar area as each other, and within each sub-mask, the shape of the hole-forming portion is nested within a shape of the aperture.