Aliphatic Epoxy Oxetane Encapsulant for OLED Moisture Barrier
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current curable compositions for OLED devices fail to provide a transparent, non-yellowing, and moisture-barrier adhesive layer that maintains transparency and adhesion at elevated temperatures, which is critical for top emission OLEDs and full-area encapsulation designs.
Innovation Solution
A thermally curable composition comprising an aliphatic epoxy compound, an aliphatic oxetane compound, and a thermal cure initiator, which ensures transparency and non-yellowing properties by maintaining high transmittance across the visible spectrum even after exposure to heat and humidity, while providing excellent moisture barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional curable composition (epoxy resin + hydroxyl-functional compound) is used to provide good barrier properties, then moisture barrier performance is improved, but transparency is lost after exposure to elevated temperatures
Solution Approach 1:
The patent changes the chemical parameters of the curable composition by using specific aliphatic epoxy compounds with controlled molecular weights and structures. This parameter optimization allows the composition to maintain both moisture barrier properties and transparency after thermal exposure, resolving the contradiction between barrier performance and optical clarity.
Solution Approach 2:
The patent creates a composite curable composition by combining aliphatic epoxy compounds with specific oxetane compounds and thermal cure initiators. This composite formulation achieves synergistic effects where the combination provides both excellent moisture barrier properties and maintains transparency after elevated temperature exposure, overcoming the limitations of individual components.
2Productivity
If UV light cure method is used to cure adhesive, then curing speed is improved, but yellowing occurs due to UV radiation on OLED materials
Solution Approach 1:
The patent substitutes the UV light cure mechanism (photopolymerization) with a thermal cure mechanism (thermosetting). This replacement eliminates the harmful UV radiation that causes yellowing while maintaining efficient curing through controlled thermal reactions, thus resolving the contradiction between curing speed and color stability.
Solution Approach 2:
The patent changes the curing parameter from UV light exposure to thermal exposure by selecting appropriate thermal cure initiators. This parameter change allows the adhesive to cure at elevated temperatures without yellowing, maintaining both productivity and optical clarity for top emission OLED applications.
3Strength
If adhesive is applied to entire surface (full area encapsulation), then mechanical strength is improved, but transparency and non-yellowing properties must be maintained across the entire adhesive layer
Solution Approach 1:
The patent optimizes the chemical composition parameters of the adhesive to achieve a balance between mechanical strength and optical clarity. By controlling the molecular structure and crosslinking density through specific aliphatic epoxy and oxetane compound ratios, the adhesive provides full-area encapsulation strength while maintaining transparency and resistance to yellowing.
Solution Approach 2:
The patent formulates a composite adhesive system that combines multiple components (aliphatic epoxy compounds, oxetane compounds, and thermal cure initiators) to achieve both high mechanical strength for full-area bonding and excellent optical properties for transparency, resolving the contradiction between strength and optical clarity.
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 achieves a high initial transmittance of at least 85% at 400 nm and maintains it after aging at 85°C and 85% relative humidity for 10 days, offering a strong adhesive bond and low water vapor transmission rate, suitable for both top emission and full-area encapsulation OLED designs.
Implementation Method 1
a thermally curable composition comprising an aliphatic epoxy compound, an aliphatic oxetane compound and a thermal cure initiator
Data Source
AI summary
The present invention relates to a curable composition for the sealing, encapsulation, or laminating of electronic devices. The curable compositions according to the invention include those having an aliphatic epoxy resin, an aliphatic oxetane resin and a thermal cure initiator, wherein the compositions provide excellent transparency and good moisture barrier property after cure.