Flexible OLED Bending Area Stress Distribution via Layer Segmentation
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Solution Overview
Problem
Organic light emitting display devices using flexible substrates face damage and cracking of wiring lines and insulating layers due to bending stress, leading to malfunction, and face challenges in accommodating a large number of wiring lines or capacitors within a restricted space, making it difficult to implement a narrow bezel configuration.
Innovation Solution
The use of multiple planarization layers and a micro cover layer in the bending area to distribute stress and optimize the neutral plane, reducing the space required for metal material layers and enhancing the flexibility of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wiring lines and insulating layers are formed on a flexible substrate, then the display device achieves flexibility and can be bent, but the wiring lines and insulating layers are damaged or cracked due to stress caused by bending
Solution Approach 1:
The insulating layer is divided into multiple segments: a first insulating layer, a second insulating layer, and a third insulating layer. The first insulating layer is disposed on the substrate, the second insulating layer is disposed on the first wiring line in the bending area, and the third insulating layer is disposed on the second wiring line. This segmentation allows each layer to independently manage stress, preventing crack propagation and maintaining reliability during bending operations.
2Measurement precision
If more wiring lines or capacitors are disposed to increase resolution, then the display device achieves higher resolution, but the space or footprint area becomes insufficient
Solution Approach 1:
The patent utilizes vertical stacking to arrange wiring lines and capacitors in multiple layers (first, second, and third insulating layers with corresponding wiring lines). This three-dimensional arrangement allows more wiring lines and capacitors to be disposed within a restricted horizontal space, enabling higher resolution without increasing the footprint area.
3Area of stationary object
If the bezel area is increased to accommodate wiring lines or capacitors, then there is sufficient space for components, but it becomes difficult to implement a narrow bezel configuration
Solution Approach 1:
By stacking insulating layers and wiring lines vertically (first insulating layer with first wiring line, second insulating layer with second wiring line, third insulating layer), the patent accommodates more wiring lines and capacitors within a compact horizontal footprint. This enables narrow bezel configuration while providing sufficient space for all necessary components through vertical arrangement.
Data Source
AI summary
An organic light emitting display device includes a substrate in which an active area and a bending area are defined, a thin film transistor on the substrate in the active area, a first wiring line on the substrate in the bending area, a first planarization layer which is on the thin film transistor in the active area and on the first wiring line in the bending area, a second wiring line on the first planarization layer in the bending area, a second planarization layer which is on the first planarization layer in the active area and on the first planarization layer and the second wiring line in the bending area, an organic light emitting element on the second planarization layer in the active area, and a micro-cover layer on the second planarization layer in the bending area.