Light-Emitting Element Ink Surfactant Control for Uniform Display Printing
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Solution Overview
Problem
Existing display devices face challenges in achieving uniform distribution and alignment of light-emitting elements due to high surface tension of light-emitting element ink, leading to non-uniform luminance and processability issues during printing.
Innovation Solution
Incorporating a fluorine-based or silicon-based surfactant into the light-emitting element ink to reduce its surface tension, allowing for even spreading and improved dispersibility of light-emitting elements on the substrate, which are then aligned using an electric field and solvent removal techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If light-emitting element ink with high surface tension is used, then the ink maintains structural integrity during handling, but the ink cannot spread uniformly on the substrate leading to non-uniform distribution of light-emitting elements
Solution Approach 1:
The patent applies parameter changes by modifying the surface tension parameter of the ink through surfactant addition. The surfactant concentration is optimized to achieve a specific surface tension range (28-38 dyn/cm), which enables uniform ink spreading and even distribution of light-emitting elements on the substrate without compromising ink stability during handling.
Solution Approach 2:
The patent introduces a surfactant as an intermediary substance between the ink and substrate. This surfactant acts as a mediator that reduces surface tension and improves wetting properties, allowing the ink to spread uniformly on the substrate while maintaining the structural integrity of the light-emitting elements during the printing process.
2Ease of operation
If surfactant is added to reduce surface tension, then ink spreads evenly on substrate, but excess surfactant may cause foaming or stability issues
Solution Approach 1:
The patent carefully controls the surfactant concentration parameter within an optimized range (0.01-1 part by weight based on 100 parts by weight of ink). This parameter optimization ensures sufficient surface tension reduction for uniform spreading while preventing excessive surfactant that could cause foaming or formulation instability, thus maintaining ink reliability.
Solution Approach 2:
The patent applies partial action by using a controlled, moderate amount of surfactant rather than excessive quantities. This optimized dosage achieves the necessary surface tension reduction for good spreading without introducing harmful side effects such as foaming or reduced ink stability, balancing ease of operation with formulation reliability.
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 surfactant reduces the surface tension of the ink to 28-38 dyn/cm, enabling even distribution and alignment of light-emitting elements, enhancing the uniformity of the display device's luminance and process reliability.
Implementation Method 1
a light-emitting element ink including: a light-emitting element solvent, light-emitting elements dispersed in the light-emitting element solvent, and a surfactant dispersed in the light-emitting element solvent, the surfactant including a fluorine-based and/or a silicon-based surfactant. In an exemplary embodiment, the light-emitting element ink has a surface tension in a range of 28 dyn/cm to 38 dyn/cm.
Implementation Method 2
spraying the light-emitting element ink onto the target substrate, settling the light-emitting elements on the first and second electrodes by generating an electric field on the target substrate
Implementation Method 3
removing the light-emitting element solvent
Data Source
AI summary
A light-emitting element ink, a display device, and a method of fabricating the display device are provided. The light-emitting element ink includes a light-emitting element solvent, light-emitting elements dispersed in the light-emitting element solvent, each of the light-emitting elements including a plurality of semiconductor layers and an insulating film that surrounds parts of outer surfaces of the semiconductor layers, and a surfactant dispersed in the light-emitting element solvent, the surfactant including a fluorine-based and/or a silicon-based surfactant.