OLED Pixel Electrode Sidewall Patterning for High-Resolution Displays
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Solution Overview
Problem
The manufacturing of high-resolution, high-definition, and large display devices with organic EL devices is hindered by issues such as non-uniform thickness of island-shaped light-emitting layers due to metal mask blurring and the need for multiple equipment lines, leading to reduced yield and increased initial investment.
Innovation Solution
A method involving the formation of island-shaped light-emitting layers using sacrificial layers and resist masks, followed by the use of sidewalls to cover side surfaces, eliminating the need for additional masks and reducing layer thickness variations, thereby enabling high-resolution and high-definition display devices with improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a metal mask is used in vacuum evaporation to form island-shaped light-emitting layers, then the light-emitting layers can be formed with specific patterns, but the outline of the layer blurs during vapor deposition causing non-uniform thickness and reduced manufacturing precision
Solution Approach 1:
The patent introduces a sacrificial layer as an intermediary between the substrate and the light-emitting layer. This sacrificial layer is formed with precise patterns using photolithography, and the light-emitting layer is deposited over it. The sacrificial layer acts as a mediator that enables precise pattern transfer without requiring metal masks, thereby achieving both ease of manufacture and high manufacturing precision.
Solution Approach 2:
The patent replaces the mechanical metal mask system with a photolithography-based patterning system. Instead of using physical masks that blur during vapor deposition, the invention uses photoresist patterns and sacrificial layers that can be precisely defined through photolithographic processes, substituting the mechanical masking approach with a chemical/photochemical patterning approach.
2Productivity
If multiple manufacturing equipment lines are prepared for mass production to maintain continuous operation, then production continuity is ensured, but the initial investment for introducing manufacturing equipment significantly increases
Solution Approach 1:
The patent merges multiple manufacturing functions into a single equipment line by implementing a process where sacrificial layers are formed and then reused as templates for multiple light-emitting layer depositions. This allows one equipment line to handle what would traditionally require multiple lines, reducing initial investment while maintaining mass production capability.
Solution Approach 2:
The patent employs preliminary action by forming sacrificial layers in advance that serve as reusable templates. These pre-formed sacrificial layers enable subsequent light-emitting layer depositions to proceed efficiently on the same equipment line without requiring separate masking and alignment processes, thereby reducing the number of equipment lines needed.
3Measurement precision
If high-resolution and high-definition display devices are manufactured with large size, then the display quality is improved, but the manufacturing yield is reduced due to low dimensional accuracy of metal masks and deformation
Solution Approach 1:
The sacrificial layer serves as a precise intermediary template that transfers patterns to the light-emitting layer with high fidelity. This intermediary approach eliminates the dimensional inaccuracies and deformation issues associated with metal masks, enabling high-resolution patterning while maintaining manufacturing yield through precise and repeatable pattern transfer.
Solution Approach 2:
The patent substitutes the metal mask mechanical system with a photolithography-based system using sacrificial layers. This substitution eliminates the problems of mask blurring, dimensional inaccuracy, and heat-induced deformation, thereby achieving high display resolution while maintaining high manufacturing yield through more reliable patterning processes.
Data Source
AI summary
A high-resolution or high-definition display device is provided. The display device is manufactured by forming a conductive film, a first layer, and a first sacrificial layer; processing the first layer and the first sacrificial layer to expose part of the conductive film; forming a second layer over the first sacrificial layer and the conductive film; forming a second sacrificial layer; processing the second layer and the second sacrificial layer to expose part of the conductive film; processing the conductive film to form a first pixel electrode overlapping with the first sacrificial layer and a second pixel electrode overlapping with the second sacrificial layer; forming an insulating film covering at least side surfaces of the first pixel electrode, the second pixel electrode, the first layer, and the second layer, side and top surfaces of the first sacrificial layer, and side and top surfaces of the second sacrificial layer; processing the insulating film to form a sidewall covering at least the side surfaces of the first pixel electrode, the second pixel electrode, the first layer, and the second layer; removing the first sacrificial layer and the second sacrificial layer; and forming a common electrode over the first layer and the second layer.