Single-Layer Pixel-Defining Layer for Inkjet Printing
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Solution Overview
Problem
Current display devices face challenges in achieving improved display quality and manufacturing process efficiency, particularly in the formation of light-emitting layers using inkjet printing, where liquid repellency and lyophilic properties are crucial but often require complex multi-layer structures and processes.
Innovation Solution
A display device with a pixel-defining layer having a single-layer structure that integrates a first portion with liquid repellency and a second portion with lyophilic properties, formed through a single exposure process, allowing for efficient inkjet printing of a light-emitting layer that covers the second portion while avoiding the first portion, thereby enhancing manufacturing efficiency and display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-layer pixel-defining structure is used, then device complexity is reduced and manufacturing cost decreases, but achieving both liquid repellency and lyophilic properties becomes difficult
Solution Approach 1:
The patent applies local quality by creating different surface properties (liquid repellent and lyophilic regions) within a single-layer pixel-defining structure. The pixel-defining layer includes a first region with liquid repellent properties and a second region with lyophilic properties, allowing each region to perform its specific function while maintaining a simplified single-layer overall structure.
Solution Approach 2:
The patent segments the single-layer pixel-defining layer into distinct functional regions - a first region containing liquid repellent and a second region without liquid repellent (lyophilic). This segmentation allows different surface properties to coexist in one layer, enabling the light-emitting layer to be selectively formed in specific areas while maintaining manufacturing simplicity.
2Manufacturing precision
If multi-layer pixel-defining structures are used to achieve liquid repellency and lyophilic properties, then surface property control improves, but manufacturing process complexity and cost increase
Solution Approach 1:
The patent merges the functions of multiple layers into a single-layer structure by incorporating both liquid repellent and lyophilic regions within one pixel-defining layer. This combining approach achieves precise surface property control (preventing light-emitting layer formation in non-emitting areas while enabling it in emitting areas) without requiring multiple sequential deposition processes, thereby simplifying manufacturing.
3Manufacturing precision
If complex multi-step processes are used to form pixel-defining layers with different surface properties, then display quality improves, but manufacturing efficiency decreases
Solution Approach 1:
The patent applies preliminary action by pre-forming the pixel-defining layer with spatially differentiated surface properties (liquid repellent and lyophilic regions) before the inkjet printing process. This preliminary structuring enables the light-emitting layer to be deposited selectively in emitting areas only, ensuring high display quality while reducing manufacturing steps and improving efficiency.
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 solution enables concurrent realization of liquid repellency and lyophilic properties in a single-layer structure, reducing costs and increasing the efficiency of the inkjet printing process, leading to improved display quality and manufacturing efficiency.
Implementation Method 1
a first portion having a first thickness and having an upper surface having liquid repellency
Implementation Method 2
a second portion having a second thickness that is less than the first thickness and having an upper surface that is lyophilic
Implementation Method 3
a contact angle of the composition for the light-emitting layer with respect to the upper surface of the first portion is about 50 degrees to about 70 degrees, and wherein a contact angle of the composition for the light-emitting layer with respect to the upper surface of the second portion is about 10 degrees to about 20 degrees
Implementation Method 4
The pixel-defining layer may include a liquid repellent containing a fluorine-based material, wherein a density of the liquid repellent in an area adjacent to the upper surface of the first portion is greater than a density of the liquid repellent in an area adjacent to the upper surface of the second portion
Data Source
AI summary
A display device includes a substrate having light-emitting areas, a pixel electrode above the substrate, a pixel-defining layer exposing a portion of the pixel electrode, and including a first portion having a first thickness and having an upper surface having liquid repellency, and a second portion having a second thickness that is less than the first thickness and having an upper surface that is lyophilic, and a light-emitting layer above the pixel electrode.