Deposition Mask for Irregular Organic EL Substrates
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Solution Overview
Problem
Existing deposition masks struggle to accurately deposit organic materials on substrates with irregular surfaces, leading to unintended deposition on sidewalls and color mixing between pixels in organic EL display devices, while also requiring multiple masks and processes for different sub-pixels, resulting in material waste and increased manufacturing complexity.
Innovation Solution
A deposition mask with a resin film having a flat surface and an uneven surface corresponding to the substrate's irregularity, featuring tapered openings that match the vapor deposition angle to prevent material blockage and ensure precise placement, is used, along with a manufacturing method involving a dummy substrate and laser beam irradiation to form the mask pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a film-like deposition mask is mounted on a substrate with irregular surface, then the mask can be applied to the substrate, but the mask cannot completely cover the concavity of the substrate, causing deposition material to enter the concavity and be deposited at unnecessary places
Solution Approach 1:
The mask surface structure is inverted to match the substrate irregularity. Instead of a flat mask attempting to cover an uneven surface, the mask is formed with convex portions that correspond to the concavities of the substrate, allowing the mask to conformally cover the entire substrate surface including all concavities, thereby preventing deposition material from entering unnecessary areas
Solution Approach 2:
The mask replicates the inverse topology of the substrate surface. By copying the substrate's irregularity pattern and inverting it, the mask creates a complementary surface that fits perfectly over the substrate, ensuring complete coverage of concavities while maintaining precise alignment with the substrate features
2Device complexity
If a flat deposition mask is used on a substrate with irregular surface, then the mask structure is simple, but the deposition material is deposited on sidewalls of banks, causing color mixing between pixels
Solution Approach 1:
The mask surface structure is inverted to match the substrate irregularity. Instead of a flat mask attempting to cover an uneven surface, the mask is formed with convex portions that correspond to the concavities of the substrate, allowing the mask to conformally cover the entire substrate surface including all concavities, thereby preventing deposition material from entering unnecessary areas
Solution Approach 2:
Different regions of the mask have different surface heights tailored to the local substrate topology. The mask features convex portions in areas corresponding to substrate concavities and flat regions corresponding to substrate convexities, creating locally adapted coverage that prevents sidewall deposition while maintaining overall structural simplicity
3Manufacturing precision
If multiple deposition masks are used for different RGB sub-pixels, then each sub-pixel can be deposited accurately, but the manufacturing process becomes complex and material waste increases
Solution Approach 1:
Multiple deposition masks for R, G, and B sub-pixels are merged into a single integrated mask structure. The unified mask contains all necessary opening patterns for different sub-pixels in one component, eliminating the need for sequential mask changes and enabling simultaneous or continuous deposition of multiple colors without process interruption
Solution Approach 2:
The deposition mask is designed with multi-functionality to serve all RGB sub-pixel deposition needs. By incorporating multiple opening patterns and varying aperture characteristics within a single mask, the system achieves universal applicability for depositing different organic materials for different colors without requiring separate specialized masks
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 allows for accurate, uniform deposition of organic materials on substrates with irregular surfaces, preventing unwanted deposition on sidewalls and reducing material waste, while enabling efficient manufacturing of organic EL display devices with improved display quality and simplified processes.
Implementation Method 1
irradiating the mask member with a laser beam to provide an opening pattern for forming a mask
Implementation Method 2
vapor depositing an organic material via the opening of the mask
Data Source
AI summary
A deposition mask and a manufacturing method thereof capable of performing vapor deposition at a desired place, without causing any gap between the deposition mask and a substrate for vapor deposition having a surface of irregularity, even when depositing a vapor deposition material only at a predetermined place on a bottom part of the substrate for vapor deposition, are provided. The manufacturing method includes preparing a dummy substrate having irregularity corresponding to a surface shape of the substrate for vapor deposition (step S1), coating a liquid resin material on an uneven surface of the dummy substrate to form a resin coating layer (step S2), and raising the temperature of the resin coating layer and baking the resin coating layer to obtain a baked resin film (step S3). The manufacturing method further includes forming a desired opening pattern on the baked resin film attached to the dummy substrate to obtain a resin film having the desired opening pattern (step S4), and subsequently peeling off the resin film from the dummy substrate to obtain a deposition mask (step S6).