Double-Layer Pixel Defining Layer for OLED Ink-Jet Printing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for forming organic thin films in OLED and PLED devices face challenges in achieving uniform thickness, particularly with ink-jet printing, which struggles to produce consistent films in pixel areas.
Innovation Solution
A double-layered pixel defining layer is created, comprising a lyophilic inorganic material as the first layer and a lyophobic organic material as the second layer, where the inorganic material is treated to enhance its lyophobic properties, allowing for precise ink-jet printing and subsequent removal of exposed inorganic material between pixel regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ink-jet printing is used to form organic film in pixel area, then equipment cost is reduced and large-scale production is enabled, but the organic film thickness uniformity deteriorates
Solution Approach 1:
The patent introduces a pixel defining layer as an intermediary structure between the substrate and the organic film. This layer includes a lower sub-layer and an upper sub-layer that work together to control the ink-jet printing process. The lower sub-layer provides a base structure while the upper sub-layer, with its specific surface energy characteristics, prevents ink solution from spreading laterally, thereby ensuring uniform organic film thickness in the pixel area while maintaining the cost benefits of ink-jet printing
Solution Approach 2:
The pixel defining layer exhibits local quality differentiation through its two-sub-layer structure. The lower sub-layer and upper sub-layer have different material compositions and surface energy properties. The upper sub-layer specifically is designed with hydrophobic/oleophobic characteristics to locally control the ink solution behavior at the pixel region boundary, preventing unwanted spreading while allowing controlled deposition in the intended pixel area
2Manufacturing precision
If vacuum deposition is used to form organic film, then uniform thickness is achieved, but equipment investment increases and large-sized product manufacturing becomes difficult
Solution Approach 1:
The pixel defining layer acts as a mediator that enables conventional ink-jet printing equipment to achieve uniform film thickness results previously only attainable with vacuum deposition. By controlling the surface energy of the pixel defining layer, the ink solution is constrained to deposit uniformly within the pixel area without requiring complex vacuum deposition equipment, thus achieving large-scale manufacturing capability with standard printing equipment
Solution Approach 2:
The patent changes the surface energy parameters of the pixel defining layer, specifically making the upper sub-layer hydrophobic/oleophobic. This parameter change fundamentally alters the ink solution deposition behavior, causing it to form uniform films through capillary action and surface tension control rather than requiring vacuum deposition conditions. This enables uniform film formation with simple, cost-effective printing equipment
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 enables uniform organic film formation using ink-jet printing, reduces production costs by eliminating the need for multiple masks, and enhances manufacturing efficiency while serving as a protective and lyophobic layer during dry etching.
Implementation Method 1
the first defining layer is made of a lyophilic inorganic material; and the second defining layer is made of a lyophobic organic material
Implementation Method 2
treating the surface of the lyophilic inorganic material by carbon tetrafluoride and fluorinated silane, so that the water contact angle on the surface of the lyophilic inorganic material ranges from 60° to 120°
Data Source
AI summary
The present invention relates to the field of display technology, particularly to a pixel defining layer, an organic electroluminescent device and a display device. The pixel defining layer comprises a first defining layer on an array substrate and a second defining layer on the first defining layer, wherein the first defining layer is made of a lyophilic inorganic material, and the second defining layer is made of a lyophobic organic material. The present invention provides a pixel defining layer, an organic electroluminescent device and a display device, wherein ink-jet printing technology is used to patternize pixels of an organic material, which serves as not only a protective layer on the first inorganic material layer during dry etching, but also a lyophobic layer on the second layer; the making of the double-layered pixel defining layer omits the process of using two masks, which can effectively reduce costs and improve production efficiency.