OLED Encapsulation Using Black Mask Sealant Coating
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Solution Overview
Problem
Existing methods for encapsulating organic light emitting display devices (OLEDs) are costly and prone to moisture penetration, with conventional sealing techniques like mask aligning processes increasing material and process costs, and methods without moisture absorbents, such as frit, being susceptible to deformation and damage.
Innovation Solution
A method involving a simple process to combine a sealing member with a substrate, using a black mask to coat a first primer and UV hardening epoxy resin sealant around the OLED, eliminating the need for mask aligning and enhancing bonding force between substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mask aligning process is used when coating sealant, then the sealant can be precisely applied, but the material and process costs increase significantly
Solution Approach 1:
A black mask layer is introduced as an intermediary element on the encapsulating substrate. This mask layer serves as a guide for sealant coating, allowing precise application without requiring complex mask aligning processes. The black mask layer is formed by simple coating and drying, eliminating the need for expensive alignment equipment and procedures while ensuring accurate sealant placement around the display unit.
2Device complexity
If a film is used to seal the OLED, then the manufacturing process is simplified, but the moisture protection capability is insufficient
Solution Approach 1:
The sealing structure uses a composite approach combining an encapsulating substrate (glass or metal), a black mask layer, and a sealant material. This composite structure provides superior moisture protection compared to simple film sealing. The encapsulating substrate forms a rigid barrier, while the sealant material fills gaps and creates a hermetic seal around the display unit, preventing moisture penetration more effectively than film alone.
Solution Approach 2:
The sealing process is segmented into distinct functional layers: the encapsulating substrate provides structural support and primary barrier, the black mask layer defines the sealant application area and provides additional protection, and the sealant material creates the hermetic seal. This segmentation allows each layer to optimize its specific function while working together to achieve comprehensive moisture protection.
3Reliability
If frit is used for sealing, then moisture protection is improved, but the structure becomes susceptible to deformation and cracking under impact
Solution Approach 1:
The material properties of the sealing structure are optimized by changing parameters: the encapsulating substrate provides rigidity and strength, while the sealant material provides flexibility and adhesion. This combination maintains the moisture protection benefits of rigid materials like frit while adding the ductility and impact resistance of flexible sealant materials, preventing cracking under external impact.
4Productivity
If a simple sealing process is used without mask aligning, then productivity increases, but the sealant coating precision decreases
Solution Approach 1:
The black mask layer is formed on the encapsulating substrate before the sealant coating process. This preliminary action creates a predefined pattern that guides subsequent sealant application. The mask layer remains in place during sealant coating, ensuring precise application without requiring complex real-time alignment procedures, thus maintaining both simplicity and precision.
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 reduces manufacturing costs, increases productivity, and effectively seals OLEDs without deformation, enhancing durability and reliability by maximizing the bonding force between substrates and preventing moisture penetration.
Implementation Method 1
hardening the sealant using a UV ray
Data Source
AI summary
In a method of encapsulating an organic light emitting display device, when a lower substrate and a encapsulating substrate are encapsulated, the encapsulating process can be simplified since a sealant coating process can be performed without a mask aligning process, thereby reducing manufacturing cost. The method comprises the steps of: preparing an encapsulating substrate for encapsulating a lower substrate on which a display unit, which includes the organic light emitting display device, is formed; forming a black mask on a region of the encapsulating substrate, which is not a sealant region, corresponding to outer regions of the display unit; and forming a sealant on the sealant region.