OLED Display Substrate Channel Isolation for Inkjet Printing Uniformity
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Solution Overview
Problem
Inkjet printing for large-size OLED displays faces challenges in maintaining uniformity of functional layer thickness across sub-pixels due to nozzle volume errors, leading to non-uniform brightness and increased fabrication complexity and cost.
Innovation Solution
A display substrate design featuring an isolating layer with surrounding and separating dams that separates sub-pixel areas into channels, allowing ink drops of the same or different materials to flow uniformly, and the use of a pixel definition layer and sealing adhesives to manage ink distribution and prevent cross-channel flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If inkjet printing is used for large-size OLED displays, then material utilization ratio and large-size implementation are improved, but uniformity of functional layer thickness across sub-pixels deteriorates due to nozzle volume errors
Solution Approach 1:
The patent divides the substrate into multiple channels using isolating layers with surrounding dams and separating dams. Each channel contains multiple sub-pixels and allows ink to flow independently, enabling localized thickness uniformity within each channel while accommodating nozzle volume errors across the entire large substrate.
Solution Approach 2:
The isolating layer with dams acts as an intermediary structure between the inkjet printing process and the sub-pixel areas. It mediates the ink flow by creating controlled channels that guide ink distribution, compensating for nozzle volume variations and ensuring uniform functional layer thickness despite printing imperfections.
2Manufacturing precision
If nozzle volume correction precision is increased, then functional layer thickness uniformity is improved, but fabrication complexity and cost increase
Solution Approach 1:
The isolating layer structure with dams enables the system to self-correct ink distribution issues. The channel structure naturally guides ink flow and compensates for nozzle volume errors without requiring complex external correction systems, reducing fabrication complexity while maintaining thickness uniformity.
Solution Approach 2:
The patent changes the physical structure of the substrate by adding isolating layers and dams, transforming the ink flow parameters within each channel. This structural parameter change allows ink to distribute more uniformly within channels, compensating for nozzle volume variations without increasing fabrication complexity.
3Manufacturing precision
If isolating layer with dams is added to separate sub-pixel areas, then ink distribution uniformity is improved, but device structure complexity increases
Solution Approach 1:
The isolating layer segments the substrate into multiple channels with surrounding dams and separating dams. This segmentation creates independent ink flow paths that improve ink distribution uniformity within each channel while organizing the complexity into manageable, repeating units across the substrate.
Solution Approach 2:
The isolating layer with dams serves multiple functions simultaneously: it separates channels, guides ink flow, prevents cross-channel contamination, and compensates for nozzle volume errors. This multi-functionality justifies the added structural complexity by delivering multiple benefits from a single structural element.
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 design reduces the precision required for nozzle volume correction in inkjet printing, lowers fabrication difficulty, and improves display panel uniformity and quality by ensuring consistent ink distribution across sub-pixels.
Implementation Method 1
the plurality of sub-pixel areas are separated by the separating dams into a plurality of channels
Implementation Method 2
the pixel definition layer is a hydrophilic pixel definition layer
Implementation Method 3
the isolating layer is a hydrophobic isolating layer
Data Source
AI summary
This disclosure provides a display substrate, a display panel, and a method for fabricating the display substrate. The display substrate includes: an underlying substrate; a plurality of sub-pixel areas arranged in an array on a surface of the underlying substrate; and an isolating layer arranged on the surface of the underlying substrate, wherein the isolating layer includes a surrounding dam arranged on a periphery of the plurality of sub-pixel areas, and a plurality of separating dams arranged in parallel on an inner side of the surrounding dam, end portions of the separating dams are spaced from the surrounding dam, and the plurality of sub-pixel areas are separated by the separating dams into a plurality of channels.