OLED Encapsulation via Laser-Stripped Sacrificial Layer
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Solution Overview
Problem
The fabrication of organic light emitting diode (OLED) devices is hindered by the vulnerability to moisture and oxygen, leading to difficulties in the encapsulation process, particularly due to the use of masks which cause issues like curling, misalignment, and quality deterioration, resulting in reduced yield and increased costs.
Innovation Solution
A method involving the formation of a sacrificial layer over the light emission and pad portions, followed by the deposition of an encapsulation passivation film, with the sacrificial layer being removed using laser irradiation to avoid mask-related problems, allowing for the encapsulation of the pad area without a mask.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If masks are used during encapsulation process, then encapsulation precision is improved, but device reliability deteriorates due to mask curling and misalignment
Solution Approach 1:
The patent removes masks from the encapsulation process entirely. Instead of using masks to define the encapsulation area, the method directly forms the encapsulation passivation film over the substrate without any mask, thereby eliminating mask-related problems such as curling and misalignment while maintaining encapsulation precision through alternative process control
Solution Approach 2:
The patent introduces a sacrificial layer as an intermediary between the substrate and the encapsulation passivation film. This sacrificial layer is selectively removed using laser irradiation to create openings for pad portions, allowing the encapsulation film to be formed continuously over the display area and pad area without masks, thus resolving the contradiction between precision and reliability
2Manufacturing precision
If masks are used during encapsulation process, then encapsulation precision is improved, but productivity deteriorates due to mask-related issues
Solution Approach 1:
The patent eliminates masks from the encapsulation process, removing the source of mask-related defects and rework. This extraction of the problematic element (masks) streamlines the manufacturing process, reduces defect rates, and improves overall productivity while maintaining encapsulation precision through the maskless formation method
Solution Approach 2:
The patent replaces the mechanical mask system with a laser-based selective removal process. Instead of using physical masks that require alignment and handling, the method uses laser irradiation to selectively remove the sacrificial layer, substituting a more precise and efficient optical process that eliminates mask-related productivity bottlenecks
3Reliability
If encapsulation process is performed, then device reliability is improved by preventing moisture and oxygen intrusion, but device complexity increases
Solution Approach 1:
The patent merges the encapsulation process with the overall device fabrication process by forming the encapsulation passivation film continuously over both the display area and pad area in the same process step. This integration eliminates separate encapsulation steps and reduces process complexity while maintaining comprehensive protection against moisture and oxygen
Solution Approach 2:
The encapsulation passivation film serves multiple functions simultaneously: it provides moisture and oxygen barrier protection for the organic light emitting layer, acts as a planarization layer, and forms a continuous protective covering over both display and pad areas. This multi-functionality reduces the need for additional separate layers or processes, thereby reducing device complexity while enhancing reliability
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 the yield and reduces costs by eliminating mask-related issues, enabling the design of a narrow bezel and improving the productivity of OLED devices while maintaining the encapsulation integrity.
Implementation Method 1
removing the sacrificial layer and the encapsulation passivation film from the pad portion by means of irradiation of laser light
Data Source
AI summary
Disclosed is an organic light emitting diode device fabrication method that includes: preparing a substrate which is defined into a display area and a non-display area; forming a light emission portion, which includes a thin film transistor and an organic light emission layer in the display area, and a pad portion in a part of the non-display area; sequentially forming a sacrificial layer and an encapsulation passivation film throughout the display and non-display areas; and separating the sacrificial layer and the encapsulation passivation film from the pad portion through an irradiation of laser light.