OLED Display Device Pixel Division Structure Without Fine Masks
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Solution Overview
Problem
The formation accuracy of organic layers in OLED display devices is degraded due to processing inaccuracies and deformation of fine masks, leading to challenges in forming organic layers in desired shapes without fine masks, and there is a need to suppress cracks near pixel division structures.
Innovation Solution
A display device manufacturing method that forms lower electrodes, insulating layers, power supply lines, organic layers, and upper electrodes without using fine masks, utilizing sacrificial layers and inorganic insulating films to create a reliable and crack-resistant structure, allowing for the formation of organic layers in desired shapes and improving manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fine mask is applied for mask deposition, then the organic layer can be formed in desired shapes, but the formation accuracy is degraded due to processing inaccuracies and deformation of the aperture shape
Solution Approach 1:
The pixel division structure is formed beforehand in the lower electrode before depositing the organic layer. This preliminary structure serves as a physical guide that defines the pixel regions, eliminating the need for fine masks during organic layer deposition and avoiding mask-related accuracy degradation
Solution Approach 2:
The invention extracts and removes the fine mask from the manufacturing process entirely. By using the pixel division structure in the lower electrode to define pixel regions, the problematic fine mask step is eliminated, thereby removing the source of processing inaccuracies and aperture deformation
2Ease of manufacture
If a pixel division structure is used to divide organic layer and cathode, then the organic layer can be formed without fine masks, but cracks may occur near the pixel division structure
Solution Approach 1:
The invention applies local quality by creating a protruding portion with a specific height in the pixel division structure. This localized structural modification at critical areas (near aperture edges) provides mechanical support to prevent crack formation, while maintaining the overall pixel division function. The protruding portion height is specifically controlled to be between 0.01 μm to 0.1 μm to optimize crack prevention
Solution Approach 2:
The protruding portion in the pixel division structure serves as a preventive measure against crack formation. By adding this structural cushioning element beforehand in the lower electrode, the invention preemptively addresses potential stress concentration points that would otherwise lead to cracks during organic layer deposition and device operation
3Manufacturing precision
If mask deposition is used, then organic layers can be formed with defined patterns, but manufacturing costs increase and positioning precision is required
Solution Approach 1:
The invention completely removes the fine mask from the manufacturing process by using the pixel division structure in the lower electrode to define pixel patterns. This eliminates mask positioning requirements and associated complexity while maintaining accurate pattern definition through the pre-formed pixel division structure
Solution Approach 2:
The pixel division structure is created in advance in the lower electrode to establish the pixel pattern. This preliminary action defines the aperture regions before organic layer deposition, eliminating the need for subsequent mask-based patterning steps and their associated positioning precision requirements
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 method enhances the reliability of OLED display devices by reducing manufacturing costs, eliminating the need for precise mask positioning, and effectively suppressing undesired light emission and cracking, while ensuring consistent light emission and extended viewing angles.
Implementation Method 1
an inorganic insulating film covering the upper electrodes and exposing the power supply line
Data Source
AI summary
According to one embodiment, a display device includes a first lower electrode and a second lower electrode, a power supply line, a first organic layer including a light emitting layer and covering the first lower electrode, a second organic layer including a light emitting layer and covering the second lower electrode, a first upper electrode being in contact with the power supply line and covering the first organic layer, a second upper electrode being in contact with the power supply line and covering the second organic layer, and a first inorganic insulating film covering the first upper electrode and the second upper electrode and exposing the power supply line.