OLED Panel Inorganic Overhang Structures for Residue-Free Pixel Patterning
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Solution Overview
Problem
Current OLED pixel patterning processes leave behind organic material residues that disrupt performance and limit pixel resolution and panel size, necessitating improved methods for sub-pixel circuit formation.
Innovation Solution
The use of inorganic overhang structures in sub-pixel circuits, combined with evaporation deposition, ensures that OLED material and cathode deposition occur without contacting residue-forming organic material, allowing for increased pixel density and improved performance by eliminating the need for lift-off procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photo lithography is used to pattern pixels instead of fine metal mask, then pixel resolution and panel size can be improved, but organic material residues are left behind that disrupt OLED performance
Solution Approach 1:
The patent extracts and removes the problematic organic material residues from the pixel patterning process by using a lift-off technique where a sacrificial organic layer is deposited and then removed, taking the residues away rather than leaving them on the substrate
Solution Approach 2:
The patent introduces an intermediary sacrificial organic layer that mediates between the photo lithography patterning process and the final pixel structure. This intermediary layer enables precise patterning while being completely removable, thus solving the residue problem
2Manufacturing precision
If lift-off procedures are used to remove organic material after patterning, then pixel definition can be achieved, but particle issues arise that disrupt OLED performance
Solution Approach 1:
The patent changes the physical and chemical parameters of the organic material used in the lift-off process, selecting materials with specific solubility characteristics that enable complete removal without leaving particles. The parameters of the removal solvent and process conditions are optimized to ensure clean dissolution
3Ease of manufacture
If current OLED pixel patterning processes are used, then manufacturing can proceed with existing methods, but pixel-per-inch density and throughput are limited
Solution Approach 1:
The patent segments the pixel patterning process into distinct stages: photo lithography for pattern definition, sacrificial layer deposition for material placement, and controlled removal for final structure formation. This segmentation enables higher density by allowing precise control at each stage without compromising manufacturing feasibility
Solution Approach 2:
The patent adds a temporal dimension to the patterning process by introducing a sacrificial layer that is deposited and then removed in a subsequent step. This dimensional approach to process sequencing enables higher pixel density while maintaining ease of manufacture through standardized process modules
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 enhances pixel-per-inch density and improves OLED performance by maintaining inorganic overhang structures in place, reducing particle issues and increasing throughput.
Implementation Method 1
depositing the OLED material using evaporation deposition over a substrate
Implementation Method 2
depositing the OLED material using evaporation deposition over a substrate
Data Source
AI summary
Embodiments described herein relate to sub-pixel circuits and methods of forming sub-pixel circuits that may be utilized in a display such as an organic light-emitting diode (OLED) display. The device includes a plurality of sub-pixels, each sub-pixel of the plurality of sub-pixels defined by adjacent pixel-defining layer (PDL) structures with inorganic overhang structures disposed on the PDL structures, each sub-pixel having an anode, organic light-emitting diode (OLED) material disposed on the anode, and a cathode disposed on the OLED material. The device is made by a process including the steps of: depositing the OLED material and the cathode by evaporation deposition, and depositing an encapsulation layer disposed over the cathode.