OLED Edge Stress Distribution for Encapsulation Protection
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Solution Overview
Problem
OLED displays in devices like smart watches are prone to damage during the rolling lamination process due to concentrated stress, which can compromise the thin film encapsulation layer and lead to moisture permeation, damaging the OLED and pixel circuit.
Innovation Solution
The OLED display incorporates a stress distribution portion at the edge with a curved or angular shape, featuring insulating layers and openings arranged in specific angles to distribute stress, along with a crack preventing metal pattern and polarizer overlap to mitigate damage during manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the OLED display uses a thin film encapsulation layer to reduce thickness, then the display device can be thinner and more flexible, but the thin film encapsulation layer becomes vulnerable to damage from concentrated stress during rolling lamination process
Solution Approach 1:
The patent applies local quality by adding a stress distribution layer specifically at the edge portion of the substrate where stress concentrates during rolling lamination. This layer is not uniformly distributed across the entire substrate but is localized to the vulnerable edge region, providing enhanced stress distribution capability exactly where needed without adding unnecessary complexity to the overall structure.
Solution Approach 2:
The stress distribution layer is formed before the rolling lamination process to preemptively address the stress concentration issue. By preparing this protective structure in advance at the edge portion, the patent prevents damage to the thin film encapsulation layer during the subsequent lamination process, rather than attempting to repair damage after it occurs.
2Shape
If the edge portion has a curved surface shape or angular shape to improve aesthetics and flexibility, then the display device can be more visually appealing and adaptable to different form factors, but stress concentration occurs at the edge portion during manufacturing processes
Solution Approach 1:
The patent addresses stress concentration at the shaped edge portion by applying a stress distribution layer specifically to this region. The layer's material properties and structural characteristics are optimized for stress distribution, creating a localized solution that preserves the aesthetic and functional benefits of the curved or angular edge shape while compensating for the mechanical weakness introduced by the geometry.
Solution Approach 2:
The stress distribution layer is formed using a composite structure comprising multiple layers with different material properties. This composite approach allows the edge portion to maintain its desired curved or angular shape while the layered composite structure provides enhanced stress distribution capabilities, combining aesthetic form with mechanical function.
3Reliability
If stress distribution portions and openings are added to the edge portion to distribute stress, then damage to the thin film encapsulation layer is prevented, but the device complexity increases
Solution Approach 1:
The patent minimizes device complexity by confining the stress distribution features to the edge portion only. The stress distribution portions and openings are localized to this specific region rather than being distributed throughout the entire display structure. This localized approach provides the necessary protection against stress concentration while avoiding unnecessary complexity in the main display area.
Solution Approach 2:
The stress distribution layer is segmented into discrete portions and openings rather than being a continuous uniform structure. This segmentation allows stress to be distributed through multiple discrete pathways, enhancing the protective function while maintaining manufacturing feasibility and controlling overall structural complexity.
Data Source
AI summary
An organic light-emitting diode display and a method of manufacturing the same are disclosed. In one aspect, the OLED display includes a substrate including a display area configured to display an image, a peripheral area surrounding the display area, and an edge portion disposed at the peripheral area and having a curved shape or an angular shape. The display also includes a plurality of pixels disposed at the display area and including a plurality of transistors and a plurality of insulating layers disposed over the transistors. The display further includes a thin film encapsulation layer covering the pixels in the display area and at least a portion of the peripheral area, and a stress distribution portion disposed at the edge portion and including at least one of the insulating layers.