OLED Bank Structure for Inkjet Printing Color Mixing
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Solution Overview
Problem
The existing methods for forming an organic light emitting layer through a solution process face challenges with ink color mixing and thickness variations, which affect the display quality and resolution of organic light emitting display devices.
Innovation Solution
The proposed solution involves a specific arrangement of horizontal and vertical banks around sub-pixels, where the distance between certain vertical banks is greater than the distance between the banks surrounding a sub-pixel, allowing for a wider area for ink injection to minimize color mixing and thickness variations, and using hydrophilic and hydrophobic materials for the banks to control ink spreading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a solution process is used to form the organic light emitting layer by injecting ink through a mask, then manufacturing simplicity and large area production are improved, but ink color mixing occurs and thickness variations are caused
Solution Approach 1:
The patent divides the light emitting area into multiple sub-pixels (first sub-pixel, second sub-pixel, third sub-pixel) with distinct color regions. Each sub-pixel is surrounded by vertical banks that segment the ink injection zones, preventing color mixing between adjacent sub-pixels while maintaining the simplicity of the solution process manufacturing method.
Solution Approach 2:
The patent applies different properties to different parts of the bank structure. The vertical banks are configured with specific heights and positions to create localized control over ink flow. The first vertical bank has a different height than the second vertical bank, creating localized quality differences that control ink spreading behavior in specific regions to prevent color mixing.
2Manufacturing precision
If the distance between vertical banks is increased to prevent ink color mixing, then color mixing is reduced, but the area for ink injection is reduced
Solution Approach 1:
The patent controls ink flow not only in the horizontal plane but also in the vertical dimension by varying the heights of different vertical banks. The first vertical bank has a first height and the second vertical bank has a second height different from the first height. This dimensional variation creates different ink flow resistance in different regions, allowing adequate injection area while preventing color mixing through vertical confinement.
3Ease of manufacture
If the vertical banks are arranged in a straight line, then manufacturing is simple, but thickness variation in the organic light emitting layer occurs
Solution Approach 1:
The patent employs asymmetric arrangement of vertical banks where the first vertical bank and second vertical bank are positioned at different distances from adjacent horizontal banks. The distance between the first vertical bank and the third horizontal bank differs from the distance between the second vertical bank and the fourth horizontal bank. This asymmetric positioning compensates for ink flow variations and reduces thickness variation in the organic light emitting layer.
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 arrangement reduces ink color mixing and thickness variations, leading to improved display quality and the ability to implement high-resolution organic light emitting display devices without complex design changes or equipment modifications.
Implementation Method 1
using hydrophilic and hydrophobic materials for the banks to control ink spreading
Data Source
AI summary
The present disclosure relates to an organic light emitting display device. According to an aspect of the present disclosure, an organic light emitting display device includes a plurality of sub-pixels including a first sub-pixel, a second sub-pixel and a third sub-pixel, a first electrode, a horizontal bank including a first horizontal bank and a second horizontal bank that are alternately arranged in a first direction to cover edges of the first electrodes, a vertical bank including a first vertical bank, a second vertical bank, and a third vertical bank that are alternately arranged in a second direction to cover edges of the first electrode and disposed on the horizontal bank, an organic light emitting layer and a second electrode. Wherein an area wider than the first sub-pixel is formed on the first horizontal bank or the second horizontal bank adjacent to the first sub-pixel, and ink is injected on the area, whereby color mixing of the ink can be minimized. And, a high-resolution organic light emitting display device can be implemented, simultaneously with improving display quality of the organic light emitting display device.