Mask Assembly with Precision Electroformed Openings for Display Deposition
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Solution Overview
Problem
Existing display apparatus manufacturing techniques face challenges in achieving high light transmittance and deposition quality, particularly in regions where display elements are not arranged, such as the transmissive area of organic light-emitting display apparatuses.
Innovation Solution
A mask assembly with a first mask and a second mask, where the second mask is electro-formed with precise openings having a curvature radius of 6 μm or less, a shortest distance between openings of 10 μm or less, and a hump protrusion, is used to deposit materials on a display substrate, ensuring improved alignment and deposition quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional mask assembly is used for deposition, then the deposition process can be completed, but the light transmittance in transmissive areas is insufficient and deposition quality is poor
Solution Approach 1:
The mask assembly is divided into multiple masks (first mask, second mask, and third mask) with different opening patterns. Each mask serves a specific function: the first mask defines the overall deposition area, the second mask creates the transmissive area pattern with precise openings, and the third mask refines the pattern. This segmentation allows optimization of each mask's opening characteristics to achieve both high light transmittance in transmissive areas and precise deposition control in non-transmissive areas.
Solution Approach 2:
Different regions of the mask assembly have different opening densities and patterns tailored to local requirements. The second mask has openings specifically positioned to create transmissive areas with high light transmittance, while other regions maintain patterns for precise deposition. The opening size, shape, and distribution are locally optimized to achieve the desired optical and deposition properties in each specific area of the display substrate.
2Illumination intensity
If the opening size in the second mask is increased to improve light transmittance, then transmissive area performance improves, but alignment precision and deposition control deteriorate
Solution Approach 1:
The mask system uses multiple masks with different opening characteristics. The second mask contains openings optimized for light transmittance in transmissive areas, while the first and third masks provide boundary definition and pattern refinement. This segmentation allows the second mask openings to be larger for better transmittance without compromising overall alignment precision, as the other masks compensate for pattern definition.
Solution Approach 2:
The first mask and third mask act as intermediary elements that mediate between the second mask's large openings (for transmittance) and the required alignment precision. These masks provide additional pattern refinement and boundary control, ensuring that the larger openings in the second mask do not compromise the overall deposition accuracy and alignment precision.
3Manufacturing precision
If multiple masks are used to improve deposition quality and transmittance, then manufacturing precision and light transmittance improve, but device complexity increases
Solution Approach 1:
The deposition process is segmented into multiple stages, each handled by a specific mask. The first mask handles overall area definition, the second mask handles transmissive area pattern creation, and the third mask handles final pattern refinement. This functional segmentation improves deposition quality and transmittance by optimizing each mask's role, while the modular structure allows for systematic manufacturing and assembly.
Solution Approach 2:
Each mask in the assembly serves multiple functions: defining deposition boundaries, creating pattern features, controlling opening sizes for light transmittance, and providing alignment references. This multi-functionality reduces the need for separate specialized components, thereby managing complexity while achieving high deposition quality and optical performance.
4Manufacturing precision
If the corner curvature radius of second mask openings is reduced to 6 μm or less for precise pattern formation, then deposition quality improves, but manufacturing difficulty increases
Solution Approach 1:
The mask assembly distributes the manufacturing complexity across multiple masks rather than requiring all features in a single mask. The second mask focuses specifically on creating transmissive area openings with precise corner curvature, while other masks handle different aspects of pattern formation. This segmentation allows specialized manufacturing techniques to be applied to each mask according to its specific requirements.
Solution Approach 2:
The corner curvature radius parameter is precisely controlled at 6 μm or less in the second mask openings to achieve sharp, well-defined patterns for high deposition quality. This parameter optimization enables precise pattern formation while the electro-forming manufacturing process is specifically tuned to achieve this curvature radius, balancing manufacturing feasibility with pattern precision requirements.
5Illumination intensity
If the distance between adjacent openings in the second mask is reduced to 10 μm or less to increase transmissive area coverage, then light transmittance improves, but manufacturing tolerance requirements become stricter
Solution Approach 1:
The mask assembly divides the pattern formation task across multiple masks, with the second mask specifically responsible for creating closely-spaced openings in transmissive areas. The first and third masks provide contextual boundaries and pattern refinement, which compensates for the reduced spacing in the second mask. This segmentation allows the 10 μm or less spacing to be achieved while maintaining overall pattern accuracy through the combined action of all masks.
Solution Approach 2:
The first mask and third mask serve as intermediary structures that provide spatial context and pattern boundaries for the closely-spaced openings in the second mask. These masks help define the overall pattern geometry, which compensates for the reduced manufacturing tolerance margin created by the tight 10 μm spacing, ensuring that the closely-spaced openings still achieve the desired light transmittance without excessive tolerance stringency.
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 enhances light transmittance in transmissive areas and improves deposition quality, allowing for the efficient manufacturing of display apparatuses with enhanced performance and functionality.
Implementation Method 1
sublimating a deposition material to pass through the mask assembly to be deposited on the display substrate
Implementation Method 2
the second mask is manufactured by electro-forming
Data Source
AI summary
An apparatus for manufacturing a display apparatus includes: a mask assembly facing a display substrate; and a deposition source facing the mask assembly on a side opposite the display substrate. The mask assembly includes: a mask frame having an opening area; a first mask on the mask frame and having a first opening; and a second mask on the first mask and having a plurality of second openings overlapping with the first opening and positioned within a circumference of the first opening in a plan view. A corner curvature radius of each of the second openings is 6 μm or less.