Epoxy Encapsulation Resin for OLED Moisture Barrier
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Solution Overview
Problem
Organic light emitting diodes (OLEDs) face issues with moisture vulnerability, delamination, and degradation, leading to reliability concerns due to high water vapor permeability and outgassing.
Innovation Solution
A thermosetting composition for OLED fillers comprising a blend of epoxy resins with specific molecular weights and flake fillers, along with a cyano group-containing imidazole curing agent, which provides excellent adhesion and low water vapor permeability without the need for silane coupling agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If acrylic resins are used for encapsulation, then molding is achieved, but adhesion to substrate and moisture barrier performance are insufficient
Solution Approach 1:
The patent uses a composite encapsulation resin system combining epoxy resin with silane coupling agents and moisture absorbent materials. This composite approach creates a material that simultaneously provides strong adhesion to the substrate and effective moisture barrier properties, resolving the contradiction between adhesion strength and moisture barrier performance.
Solution Approach 2:
Silane coupling agents are used as intermediary substances that bridge the epoxy resin and substrate interface. These coupling agents enhance both adhesion strength and moisture resistance by forming chemical bonds at the interface and creating a hydrophobic barrier layer, thus resolving the contradiction between adhesion and moisture barrier requirements.
2Reliability
If moisture absorbent material is added to encapsulation resin, then moisture protection is improved, but outgassing increases
Solution Approach 1:
The patent carefully controls the type, amount, and particle size of moisture absorbent materials added to the encapsulation resin. By optimizing these parameters, the patent achieves effective moisture protection while minimizing outgassing. The specific parameter ranges for moisture absorbent material content are established to balance moisture protection and outgassing reduction.
Solution Approach 2:
The patent distributes moisture absorbent materials selectively within the encapsulation resin matrix, concentrating them in regions where moisture protection is most critical while maintaining low outgassing in other areas. This localized quality approach allows effective moisture protection without excessive overall outgassing.
3Reliability
If metal layers are used in OLED structure, then electrical conductivity is achieved, but oxidation and delamination occur due to moisture
Solution Approach 1:
The silane coupling agents and encapsulation resin form an intermediary protective layer between the metal layers and moisture environment. This intermediate barrier prevents moisture from reaching the metal surfaces, thereby preventing oxidation and delamination while maintaining electrical conductivity of the metal layers.
Solution Approach 2:
The encapsulation resin creates an inert, moisture-excluding environment around the metal layers. By preventing moisture contact, the encapsulation system effectively creates a protective atmosphere that prevents oxidation and delamination of the metal layers while allowing them to maintain their electrical function.
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
The composition ensures reliable OLED performance by enhancing adhesion, reducing outgassing, and maintaining luminous characteristics even under humid conditions, as demonstrated by improved adhesive strength, low water vapor transmission rates, and stable luminescence over time.
Implementation Method 1
a thermosetting composition for organic light emitting diode fillers may include: 100 parts by weight of (A) an epoxy-based resin composed of (A1) an epoxy resin having a weight average molecular weight of about 200 g/mol or more to less than about 1,000 g/mol, (A2) an epoxy resin having a weight average molecular weight of about 1,000 g/mol or more to less than about 20,000 g/mol, and (A3) an epoxy resin having a weight average molecular weight of about 20,000 g/mol or more to less than about 100,000 g/mol; about 10 parts by weight to about 40 parts by weight of (B) flake fillers; and about 0.1 parts by weight to about 20 parts by weight of (C) an cyano group-containing imidazole curing agent
Data Source
AI summary
The present invention relates to a thermosetting composition for an organic light-emitting element filler, which comprises (A) 100 parts by weight of an epoxy-based resin including (A1) an epoxy resin having a weight average molecular weight of around about 200 g/mol or more to less than about 1000 g/mol, (A2) an epoxy resin having a weight average molecular weight of around about 1000 g/mol or more to less than about 20000 g/mol and (A3) an epoxy resin having a weight average molecular weight of about 20000 g/mol or more to less than about 100000 g/mol, (B) about 10 parts by weight to about 40 parts by weight of a sheet-like filler and (C) about 0.1 parts by weight to about 20 parts by weight of an imidazole curing agent having a cyano group; and an organic light-emitting element display device comprising the same.