OLED Encapsulation Layer Design for Heat Dissipation and Moisture Protection
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Solution Overview
Problem
Organic light-emitting display devices are vulnerable to heat damage and suffer from light-emitting layer deterioration during the encapsulating process, which can lead to malfunction due to hydrogen generation from inorganic materials in the upper insulating layer.
Innovation Solution
The design includes a device substrate with a light-emitting structure and encapsulating layers, where the lower encapsulating layer is in contact with the light-emitting structure and extends onto the non-display area, and an upper encapsulating layer with a moisture-absorbing material is used, along with a metal encapsulating substrate to facilitate heat dissipation and prevent moisture permeation without a curing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermosetting resin encapsulating layer is used to couple the encapsulating substrate to the device substrate, then the light-emitting structure is sealed and protected from moisture, but the light-emitting layer is deteriorated due to heat generated during operation and the curing process
Solution Approach 1:
The encapsulating layer is divided into multiple layers with different materials and functions. The lower encapsulating layer uses a thermosetting resin for strong adhesion and sealing, while the upper encapsulating layer uses a thermoplastic resin for moisture barrier protection without requiring high-temperature curing, thus protecting the light-emitting layer from heat damage.
Solution Approach 2:
Different regions of the encapsulating structure use different materials optimized for their specific functions. The lower layer near the light-emitting structure uses material with good adhesion properties, while the upper layer uses material with superior moisture barrier properties, creating localized optimization throughout the structure.
2Object-affected harmful factors
If an upper insulating layer including an inorganic material is used to prevent heat deterioration, then the light-emitting layer is protected from heat, but hydrogen is generated in the upper insulating layer causing malfunction of the light-emitting structure and driving circuit
Solution Approach 1:
The harmful curing process that generates hydrogen is completely removed from the system. Instead of using a thermosetting resin that requires high-temperature curing, the patent employs a thermoplastic resin that is applied and sealed without any chemical curing reaction, thereby eliminating hydrogen generation while still providing effective heat protection.
Solution Approach 2:
The material properties of the encapsulating layer are changed from thermosetting to thermoplastic characteristics. This parameter change allows the material to provide thermal protection through physical properties rather than chemical cross-linking, avoiding hydrogen generation while maintaining heat resistance.
3Reliability
If the encapsulating layer is cured to couple the substrates, then the structure is sealed, but the light-emitting structure is damaged by the coupling process
Solution Approach 1:
The encapsulating layer is prepared in advance as a pre-formed thermoplastic resin layer on the encapsulating substrate. This preliminary preparation allows the layer to be in place before the coupling process, providing immediate protection to the light-emitting structure during substrate bonding without requiring high-temperature curing that could cause damage.
Solution Approach 2:
The chemical curing process is replaced with a mechanical/physical sealing process. The thermoplastic resin layer is bonded through controlled cooling and pressure without chemical reactions, substituting the high-temperature chemical curing system with a lower-temperature physical bonding system that protects the light-emitting 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
This configuration enhances heat dissipation, prevents light-emitting layer deterioration, and maintains the functionality of the light-emitting structure by efficiently managing moisture and reducing the risk of damage during the encapsulating process, thereby increasing the device's reliability and lifespan.
Implementation Method 1
The upper encapsulating layer includes a moisture-absorbing material
Implementation Method 2
an encapsulating substrate disposed on the upper encapsulating layer. The encapsulating substrate includes a metal
Data Source
AI summary
An organic light-emitting display device including an encapsulating layer for coupling an encapsulating substrate to a device substrate in which a light-emitting structure is formed, is provided. The encapsulating layer can include a lower encapsulating layer and an upper encapsulating layer which are sequentially disposed on the light-emitting structure. The lower encapsulating layer can be in direct contact with the light-emitting structure. The upper encapsulating layer can include a moisture-absorbing material. Thus, in the organic light-emitting display device, the permeation of external moisture can be prevented, and the heat dissipation can be improved.