OLED Sub-Pixel Fabrication via Multi-Mask Segmentation
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Solution Overview
Problem
The existing fine metal mask (FMM) method for forming sub-pixels in OLEDs is prone to deformation due to external forces or magnetic fields, leading to low manufacturing yield and resolution issues due to the high precision and small size of the openings required.
Innovation Solution
A method involving multiple mask plates with larger opening areas, where each opening corresponds to two sub-pixel regions, allowing for the superposition of sub-pixels to form a fourth sub-pixel, thereby reducing deformation and improving precision and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If small openings are used in the FMM to form sub-pixels, then resolution is improved, but the openings are prone to deformation due to external force or magnetic field
Solution Approach 1:
The patent divides the formation of each sub-pixel into multiple steps using multiple mask plates. Instead of forming all sub-pixels in a single step with one FMM, the process segments the deposition into sequential steps, where each mask plate forms a portion of the sub-pixels. This segmentation reduces the precision requirements for individual mask openings while maintaining overall resolution.
Solution Approach 2:
The patent introduces a temporal dimension to the mask formation process by using multiple mask plates applied at different times. Rather than relying on a single static FMM with all openings, the solution uses sequential mask applications, transforming the problem from a spatial precision challenge to a temporal process control challenge.
2Manufacturing precision
If high precision openings are used in the FMM, then sub-pixel precision is improved, but manufacturing yield decreases due to deformation
Solution Approach 1:
By segmenting the sub-pixel formation process into multiple steps with multiple mask plates, the patent reduces the stress and deformation risk on individual mask openings. Each mask plate can be optimized for its specific function, and the sequential application allows for better process control, thereby improving manufacturing yield while maintaining precision.
Solution Approach 2:
The patent changes the process parameters by using multiple mask plates with potentially different opening sizes and configurations optimized for each deposition step. This allows flexibility in adjusting parameters for each step to maximize yield while maintaining overall sub-pixel precision.
3Manufacturing precision
If multiple mask plates are used to form sub-pixels, then deformation is reduced and precision is improved, but device complexity increases
Solution Approach 1:
While segmentation into multiple mask plates does increase process steps, each individual mask plate can be simpler in design with larger, more robust openings that are less prone to deformation. The complexity is distributed across multiple simpler components rather than concentrated in one highly precise FMM.
Solution Approach 2:
The multiple mask plates act as intermediaries that simplify the overall process by breaking down the complex task of forming all sub-pixels in one step into manageable sequential steps. Each mask plate serves as an intermediary tool optimized for its specific function, making the overall process more controllable and less complex.
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 approach enhances the precision and manufacturing yield of sub-pixels by reducing deformation from external forces and magnetic fields, resulting in improved resolution and illumination brightness through the formation of a white sub-pixel by mixing red, green, and blue sub-pixels.
Implementation Method 1
evaporating the materials for the sub-pixels (for example, organic light-emitting materials for forming sub-pixels in an OLED) on a low temperature poly-silicon (LTPS) backplate by way of evaporation
Implementation Method 2
forming the first sub-pixel on the first circuit and the fourth circuit by a first mask plate
Data Source
AI summary
A display substrate and a fabricating method thereof, and a system for fabricating a display substrate and a display device are disclosed. The display substrate includes a plurality of pixels, each of which includes a first sub-pixel, a second sub-pixel, a third sub-pixel and a fourth sub-pixel arranged in a first direction. The fourth sub-pixel in a first pixel is adjacent to the first sub-pixel in a second pixel, and that the second pixel is adjacent to the first pixel and at a side of the first pixel in the first direction. The fourth sub-pixel in the first pixel is adjacent to the second sub-pixel in a third pixel, and the third pixel is adjacent to the first pixel and at a side of the first pixel in a second direction perpendicular to the first direction.