Inkjet Printing Method for Color Conversion Layer Stain Prevention
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Solution Overview
Problem
The inkjet printing method for forming a color conversion layer in organic light emitting display devices often results in stains due to the precipitation of scattering elements in the inkjet printer, which affects the quality of the display.
Innovation Solution
The method involves strategically discharging ink to specific printing row areas using multiple heads of an inkjet head, with controlled discharge patterns to prevent precipitation and maintain optimal ink concentration, including the use of wavelength converting particles and scattering elements like titanium oxide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If inkjet printing method is used to form color conversion layer, then manufacturing flexibility and pattern precision are improved, but scattering elements precipitate in the inkjet printer causing stains
Solution Approach 1:
The inkjet head is divided into multiple discharge heads (first discharge head, second discharge head, third discharge head) that discharge ink to different printing row areas separately. This segmentation allows independent control of ink discharge to each row, preventing precipitation of scattering elements in any single row while maintaining pattern precision.
Solution Approach 2:
The inkjet head moves sequentially to discharge ink to different printing row areas (first printing row area, second printing row area, third printing row area) in a dynamic printing process. This dynamic approach ensures that scattering elements are distributed evenly across multiple rows rather than precipitating in one location, while maintaining the precision of the printed pattern.
2Productivity
If ink is discharged continuously to all printing row areas, then productivity is improved, but scattering elements precipitate causing non-uniform concentration
Solution Approach 1:
The printing process is segmented into multiple discrete discharge operations: first discharge head discharges to first printing row area, second discharge head discharges to second printing row area, and third discharge head discharges to third printing row area. This segmentation maintains composition stability in each row while enabling continuous high-speed printing across all rows.
Solution Approach 2:
Each discharge head is optimized for its specific printing row area, with the first discharge head targeting the first printing row area, the second discharge head targeting the second printing row area, and the third discharge head targeting the third printing row area. This local optimization ensures uniform scattering element concentration in each row while maintaining overall productivity.
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 effectively prevents stains in the color conversion layer, ensuring consistent and high-quality display performance by maintaining the concentration of scattering elements within normal limits during the printing process.
Implementation Method 1
The color conversion layer may include a wavelength converting particle such as a quantum dot, and a scattering element
Implementation Method 2
The color conversion layer may include a wavelength converting particle such as a quantum dot, and a scattering element
Data Source
AI summary
An inkjet printing method includes moving an inkjet head to discharge ink to a substrate including printing row areas, discharging ink to a first printing row area and a second printing row area among the printing row areas, discharging ink to a third printing row area among the printing row areas and the second printing row area, and discharging ink only to the first printing row area.