OLED Shadow Mask Design for Aperture Ratio and Process Simplification
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Solution Overview
Problem
The manufacturing process of organic light emitting devices is complex due to the use of different materials for red, green, and blue organic light emitting members, leading to increased process steps and reduced aperture ratios.
Innovation Solution
The design includes red, green, and blue subpixels with a common layered structure, where the blue subpixel is larger than the others, and a manufacturing method that forms the red and green organic light emitting members together using the same process, along with a shadow mask with specific openings to optimize the aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If different materials are used for red, green, and blue organic light emitting members, then color emission is achieved, but the manufacturing process becomes complex and the number of process steps increases
Solution Approach 1:
The patent merges the formation processes of red, green, and blue organic light emitting members into a single manufacturing step. By using a shadow mask with multiple openings that allows simultaneous deposition of different colored materials, the patent reduces the number of separate manufacturing processes while still achieving distinct color emissions from each subpixel.
Solution Approach 2:
The shadow mask is designed to serve multiple functions simultaneously: it defines the patterns for red, green, and blue subpixels, and enables simultaneous deposition of multiple materials through its multiple openings. This multi-functional approach simplifies the manufacturing process by eliminating the need for separate masks and processes for each color.
2Manufacturing precision
If masks are used for forming organic light emitting members of each color, then pattern formation is achieved, but the aperture ratio is reduced due to required process margins
Solution Approach 1:
The patent combines multiple pattern formation operations into a single shadow mask application. By integrating the patterning functions for red, green, and blue subpixels into one mask structure, the patent eliminates the cumulative margin requirements that would result from using separate masks for each color, thereby increasing the aperture ratio.
Solution Approach 2:
The shadow mask is designed with a specific geometric arrangement where openings for different colors are positioned to minimize overlapping margin requirements. The mask structure utilizes spatial optimization in the plane dimension to reduce the total margin area while maintaining precise pattern formation for all three colors.
Data Source
AI summary
An organic light emitting device including a blue subpixel that is larger than a red subpixel and a green subpixel. The red subpixel and the green subpixel have the same layered structure such that the red subpixel and the green subpixel are formed by using the same shadow mask.