Oleophobic Layer Increases Contact Angle for Inkjet Printing
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Solution Overview
Problem
The challenge is that the small contact angle between an ink and a black matrix layer prevents successful inkjet printing of photoresist droplets into pixel pits in flexible organic light emitting diode (OLED) display technologies, due to the low transmittance, large thickness, brittleness, and high cost of polarizers, which limits the application of these technologies.
Innovation Solution
A display panel is designed with a black matrix layer featuring through holes and an oleophobic layer composed of specific organic cationic and hydrophobic compounds, which increases the contact angle with photoresist droplets, allowing for effective inkjet printing by forming a uniform film within the through holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a black matrix layer is used in inkjet printing, then the structure is simple and material utilization is high, but the contact angle between ink and black matrix layer is too small preventing printing
Solution Approach 1:
An oleophobic layer is introduced as an intermediary between the black matrix layer and the photoresist droplets. This intermediate layer modifies the surface properties to increase the contact angle, enabling successful inkjet printing while maintaining the simplicity of the black matrix structure underneath.
Solution Approach 2:
The surface energy parameters of the black matrix layer are changed by coating it with an oleophobic layer. This parameter change increases the contact angle between the ink and the surface, transforming the surface from non-printable to printable while maintaining the underlying simple structure.
2Device complexity
If photoresist droplets are printed directly on black matrix layer, then the process is simple without photolithography mask, but the small contact angle makes printing impossible
Solution Approach 1:
The oleophobic layer serves as a mediator that enables the direct printing process to work. It provides the necessary surface properties for accurate droplet placement without requiring complex photolithography masks, thus maintaining process simplicity while achieving printing accuracy.
Solution Approach 2:
By changing the surface energy parameters through the oleophobic coating, the contact angle is increased to a range that allows for precise droplet placement and accurate printing, resolving the manufacturing precision issue while keeping the process simple.
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 oleophobic layer enhances the contact angle between photoresist droplets and the black matrix layer interface, enabling accurate ink flow into the through holes during printing, resulting in a uniform film formation and overcoming the printing limitations.
Implementation Method 1
the first compound is adsorbed on the polar anionic group, and the second compound is adsorbed on the first compound
Data Source
AI summary
A display panel and a manufacturing method thereof are provided. The display panel includes a substrate, an encapsulation layer, a black matrix layer, and an oleophobic layer. The encapsulation layer is disposed on a surface of the substrate. The black matrix layer is disposed on the encapsulation layer. The black matrix layer includes a through hole. The through hole extends through the black matrix layer to expose the encapsulation layer. The oleophobic layer covers the black matrix layer.