Low-Temperature Silicone Sealing for Organic EL Elements
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Solution Overview
Problem
The existing sealing methods for organic electroluminescent elements, such as using desiccants or epoxy resin, are inadequate in preventing degradation due to insufficient water absorption and high curing temperatures, leading to reduced light-emitting performance and potential cracking.
Innovation Solution
An addition reaction curing type silicone composition with a low curing temperature of 100 degrees C. or below and a moisture content of 400 ppm or less, comprising polyorganosiloxane, polyorganohydrogensiloxane, and a platinum-based catalyst, is used to form a sealing layer that prevents moisture-induced deterioration and thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If epoxy resin is used to seal the organic EL element, then moisture sealing is improved, but the element deteriorates due to high curing temperature and uncontrolled moisture content
Solution Approach 1:
The patent changes the curing temperature parameter from the conventional high temperature (typically 120-150°C for epoxy resin) to a low temperature of 100°C or below. This is achieved by selecting specific silicone resin systems and catalysts that enable effective curing at reduced temperatures, thereby eliminating thermal stress on the organic EL element while maintaining sealing performance.
Solution Approach 2:
The patent employs a moisture-curing silicone resin system that utilizes ambient moisture for curing, eliminating the need for high-temperature processing. The sealing composition is designed to cure at low temperatures through reaction with atmospheric moisture, providing effective sealing without subjecting the organic EL element to harmful thermal conditions.
2Reliability
If adsorbing desiccant is disposed in the hollow portion, then some moisture protection is provided, but the water-absorbing capacity is insufficient to prevent degradation
Solution Approach 1:
The patent creates a moisture-barrier sealing environment using cured silicone resin that isolates the organic EL element from atmospheric moisture. The sealing composition forms an impermeable barrier that prevents moisture ingress, effectively creating a protected inert environment around the sensitive organic components without relying on desiccant capacity.
3Ease of manufacture
If conventional sealing materials are used, then sealing is achieved, but peeling and cracking occur due to temperature changes
Solution Approach 1:
The patent modifies the thermal parameters of the sealing process by implementing low-temperature curing (100°C or below). This parameter change prevents thermal expansion mismatches and stress accumulation that would otherwise cause peeling and cracking, while still achieving complete curing and strong adhesion to the substrate and sealing flange.
Solution Approach 2:
The patent uses a composite sealing composition based on silicone resin that combines flexibility, adhesion, and moisture barrier properties. The silicone-based formulation provides elastic recovery and stress distribution capabilities that prevent cracking during thermal cycling, while maintaining strong bonding to the sealing structure.
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 solution provides a durable sealing layer that maintains excellent light-emitting properties over a long period without peeling or cracking, effectively preventing moisture and heat-related degradation of the organic electroluminescent elements.
Implementation Method 1
an addition reaction curing type silicone composition which is liquid at normal temperature and has a curing temperature of 100 degrees C. or below
Data Source
AI summary
This organic electroluminescent element sealing composition contains an addition reaction curing type silicone composition which is liquid at normal temperature and has a curing temperature of 100 degrees C. or below and a moisture content of 400 ppm or less. The addition reaction curing type silicone composition contains (A) polyorganosiloxane having an average of 0.2 to 5 alkenyl groups bonded to silicon atoms in one molecule, (B) polyorganohydrogensiloxane having at least two or more hydrogen atoms bonded to silicon atoms in one molecule, and (C) a platinum-based catalyst. The organic electroluminescent element sealing composition can prevent deterioration of the organic electroluminescent element and can provide the organic light-emitting device having a good light-emitting property for a long period.