OLED Encapsulation Compliant Regions Stress Transfer
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Solution Overview
Problem
OLED displays are sensitive to moisture and suffer mechanical damage due to stress transfer between the substrate and encapsulation container, particularly when materials with different coefficients of expansion are used, leading to issues like cracking and delamination, especially as displays become larger and flex during handling.
Innovation Solution
Incorporating compliant regions within the encapsulation container and substrate that can flex, compress, or expand to absorb stress, reducing the transfer of mechanical stress between the container and substrate, and using materials with different expansion characteristics while maintaining a robust seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the substrate and encapsulation container are rigidly connected, then structural stability is improved, but stress transfer causes mechanical damage and delamination
Solution Approach 1:
The encapsulation container is divided into rigid portions and compliant regions, creating segmented zones with different mechanical properties. The rigid portions provide structural stability while the compliant regions absorb stress, preventing stress transfer to the substrate and perimeter seal.
Solution Approach 2:
The compliant regions are formed using flexible materials that can deform elastically under stress. These flexible regions act as stress absorbers, accommodating thermal expansion differences and mechanical stresses without transmitting them to the rigid substrate or seal, thereby preventing delamination and cracking.
2Adaptability or versatility
If materials with different coefficients of expansion are used, then design flexibility is improved, but thermal stress causes cracking and delamination
Solution Approach 1:
Different regions of the encapsulation container are assigned different mechanical properties. The rigid portions use materials optimized for structural integrity while the compliant regions use materials with higher elasticity and compliance. This local differentiation allows the use of materials with different thermal expansion coefficients without causing system-wide stress problems.
Solution Approach 2:
The patent changes the mechanical parameters (compliance, elasticity, thickness) of specific regions to accommodate thermal expansion differences. By adjusting these parameters in the compliant regions, the system can tolerate a wider range of material combinations with different thermal expansion coefficients, preventing thermal stress-induced failures.
3Area of stationary object
If the display is made larger, then viewing area is improved, but flexing during handling causes stress and damage
Solution Approach 1:
The encapsulation container is designed with dynamic compliant regions that can adapt their shape and volume in response to external forces. When the larger display flexes during handling, these compliant regions deform elastically to accommodate the stress, preventing it from being transmitted to the rigid substrate and seal, thereby maintaining reliability despite increased size.
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 solution reduces damage to the substrate, encapsulation container, and perimeter seal, increasing manufacturing yield and reducing costs by minimizing stress-induced damage and allowing the use of diverse materials, while maintaining a secure moisture barrier.
Implementation Method 1
Incorporating compliant regions within the encapsulation container and substrate that can flex, compress, or expand to absorb stress
Implementation Method 2
Desiccant material is formed on the inside surface of the enclosure to protect the OLED from moisture
Data Source
Figure 1~2
Figure 3~5
AI summary
An OLED display, comprising: a substrate; an OLED having two spaced-apart electrodes and organic layers disposed there between, and the OLED disposed over the substrate; an encapsulation container fixed by perimeter seal to the substrate and disposed over the OLED to provide an enclosure; and the substrate or the encapsulation container, or both, including compliant regions that flex, compress, or expand under stress and reduce stress transfer between the substrate and the encapsulation container through the perimeter seal.