OLED Encapsulation with Parallel Frit Seals Against Moisture Ingress
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Solution Overview
Problem
Existing methods for encapsulating organic light-emitting display devices using frit seals face challenges such as incomplete melting of frit during laser irradiation, leading to weakened adhesive force and potential infiltration of oxygen or moisture, especially when dealing with large substrates, which can result in degraded device performance or loss of function.
Innovation Solution
The use of multiple frit seals, including a primary and secondary frits, interposed between substrates to form a hermetically sealed enclosure, with each frit seal attached to both substrates with or without a material, and extending in a parallel configuration to ensure consistent melting and bonding without high laser power, thereby maintaining the integrity of the seal and preventing moisture infiltration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single frit seal is used for encapsulation, then the device structure is simple, but the adhesive force is weakened and oxygen or moisture infiltration occurs due to incomplete melting
Solution Approach 1:
The encapsulation structure is divided into multiple frit seals (first frit seal and second frit seal) arranged in parallel. This segmentation allows each frit seal to contribute to the overall sealing function, ensuring that even if one frit seal has incomplete melting or delamination, the other frit seals maintain the hermetic seal integrity and prevent oxygen or moisture infiltration.
2Strength
If high laser power is used to melt and bond frit to large substrates, then bonding is achieved, but frit cracking and excessive heating occur
Solution Approach 1:
The bonding process is segmented into multiple parallel frit seals, which distributes the laser irradiation requirements. This allows the use of lower laser power for each individual frit seal while still achieving adequate bonding strength, thereby preventing frit cracking and excessive heating that would occur with high power concentration on a single large frit seal.
Solution Approach 2:
Instead of using high laser power uniformly across the entire encapsulation area, the patent applies laser irradiation locally to each parallel frit seal at lower power levels. This local quality approach ensures adequate bonding at each frit seal location without causing the harmful effects of excessive heating and frit cracking that would result from concentrated high power irradiation.
3Object-affected harmful factors
If moisture absorbent material is mounted as powder, then moisture removal is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the moisture absorption function from separate powder material applications and integrates it into the encapsulation structure itself through the frit seals. The frit seals serve dual purposes: providing hermetic sealing and containing moisture absorbent materials, thereby eliminating the need for separate powder mounting processes and reducing manufacturing complexity.
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 reliability and durability of the encapsulation by maintaining a hermetic seal even if one frit delaminates, and allows for the use of lower laser power, preventing frit cracking and excessive heating, thus improving the yield and reliability of organic light-emitting display devices, especially for large screens.
Implementation Method 1
after bonding a sealing substrate to which a frit is applied to the substrate on which the light-emitting device is formed, the frit is melted and adhered to the substrate by irradiating laser thereon
Implementation Method 2
the frit is melted and adhered to the substrate by irradiating laser thereon
Implementation Method 3
a first frit seal interposed between the first substrate and the second substrate and configured to surround the array, and a second frit seal interposed between the first substrate and the second substrate and configured to surround the array
Data Source
AI summary
Disclosed is an organic light-emitting display device comprising: a pixel region wherein an organic light-emitting device comprised of a first electrode, an organic thin film layer and a second electrode is formed; a first substrate comprising a non-pixel region encompassing the pixel region; a second substrate disposed on the upper of the first substrate to be overlapped with the pixel region and a portion of the non-pixel region; and a plurality of frits provided between the first substrate and the second substrate and formed in parallel at spaced intervals along the peripheral portion of the pixel region, wherein the first substrate is bonded to the second substrate by the plurality of frits. Even in the case that a portion of the frit is delaminated due to a partial defection thereof, its encapsulation state can be maintained as it is by being encapsulated with the frit in a multi structure and even in the case that a substrate with a large diameter is used, the width and height of the frit do not need to increase.