Flexible Light-Emitting Layer Structure for Repeated Bending
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Solution Overview
Problem
Light-emitting devices using electroluminescence (EL) elements face challenges in maintaining resistance to bending, particularly in applications requiring curved or foldable displays, with issues such as crack generation and reduced reliability during repetitive bending.
Innovation Solution
The light-emitting device is designed with specific regions devoid of inorganic films, incorporating flexible organic and inorganic insulating layers to prevent crack propagation and enhance bending resistance, while using a method to divide light-emitting devices from a large substrate to minimize crack formation during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic films are used in light-emitting devices, then reliability and protection are improved, but bending resistance and flexibility deteriorate due to crack generation
Solution Approach 1:
The patent removes inorganic films from specific regions (first regions) of the light-emitting device to prevent crack generation during bending. By extracting the rigid inorganic material from areas prone to stress concentration, the device maintains reliability in functional areas while improving overall bending resistance.
Solution Approach 2:
The patent applies different material compositions to different regions of the device. Inorganic films are retained in areas requiring protection and reliability, while flexible organic insulating layers are used in regions requiring bending resistance. This localized differentiation resolves the contradiction between reliability and flexibility.
2Reliability
If inorganic films are provided across the entire device, then protection and reliability are improved, but device thickness and weight increase
Solution Approach 1:
The patent extracts inorganic films from non-essential regions (first regions) where they do not contribute to device functionality. This removal reduces overall device weight and thickness while maintaining protection and reliability in critical areas where inorganic films remain.
Solution Approach 2:
The patent implements regional differentiation in material composition, providing inorganic films only where protection is necessary for device functionality. Flexible organic insulating layers replace inorganic films in regions where weight reduction is prioritized, achieving optimal balance between protection and lightweight design.
3Ease of manufacture
If inorganic films extend to the light-emitting portion, then manufacturing simplicity is improved, but bending resistance deteriorates due to crack propagation
Solution Approach 1:
The patent removes inorganic films from first regions that would otherwise extend to the light-emitting portion. This extraction prevents crack propagation paths while maintaining manufacturing simplicity by retaining inorganic films in other protective regions, achieving both goals through selective removal.
Solution Approach 2:
The patent applies inorganic films selectively rather than uniformly across the entire device. Inorganic films are provided in regions where manufacturing simplicity is prioritized, while flexible organic insulating layers are used in regions where crack resistance is critical, resolving the contradiction through localized material selection.
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 enables long-term, reliable operation in bent states with reduced thickness and weight, allowing for high-yield, cost-effective manufacturing of flexible display devices with improved bending resistance.
Implementation Method 1
Light-emitting elements utilizing electroluminescence (EL)
Data Source
AI summary
A light-emitting device capable of long-time display in a bent state is provided. A light-emitting device that can be repeatedly bent with a small radius of curvature is provided. The flexible light-emitting device includes a light-emitting element, a first inorganic insulating layer, a second inorganic insulating layer, and a first organic insulating layer. The first organic insulating layer is positioned over the first inorganic insulating layer. The light-emitting element is positioned over the first inorganic insulating layer with the first organic insulating layer therebetween. The second inorganic insulating layer is positioned over the light-emitting element. An end portion of the first inorganic insulating layer and an end portion of the second inorganic insulating layer are each positioned inward from an end portion of the first organic insulating layer. The end portion of the first organic insulating layer is exposed on a side surface of the light-emitting device. The first inorganic insulating layer and the second inorganic insulating layer are preferably in contact with each other outside an end portion of the light-emitting element.