OLED Cathode Mesh Structure for Bending Stress Dispersion
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Solution Overview
Problem
Flexible OLED display panels face challenges with bending-resistance and impact-resistance due to stress concentration, leading to potential damage and display defects such as dark spots, bright spots, and color spots when subjected to repeated bending or impact.
Innovation Solution
A display panel design incorporating a compensation electrode connected to the cathode via a contact hole forms a three-dimensional mesh structure, dispersing impacting stress and preventing cathode damage, thereby enhancing bending-resistance and impact-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional OLED display panel structure is used, then the display panel achieves thin thickness and flexibility, but the bending-resistance strength and impact-resistance strength are insufficient
Solution Approach 1:
The cathode is segmented into multiple cathode electrodes that are spatially separated and connected through compensation electrodes, forming a distributed network structure. This segmentation allows stress to be distributed across multiple connection points rather than concentrated at single locations, thereby improving bending-resistance and impact-resistance strength.
Solution Approach 2:
The patent introduces a three-dimensional mesh structure by adding vertical connectivity through contact holes that penetrate the pixel definition layer. This transforms a planar cathode structure into a multi-layered three-dimensional network, providing additional stress distribution pathways and improving mechanical strength without significantly increasing overall device complexity.
2Strength
If the cathode is designed as a continuous layer, then electrical connectivity is ensured, but stress concentration occurs during bending or impact leading to cathode damage
Solution Approach 1:
The continuous cathode layer is divided into multiple discrete cathode electrodes that are connected through compensation electrodes via contact holes. This segmentation prevents stress concentration by distributing mechanical loads across multiple isolated connection points, reducing the likelihood of cathode breakage or separation during bending or impact events.
Solution Approach 2:
Compensation electrodes serve as intermediary elements that connect the segmented cathode electrodes through contact holes in the pixel definition layer. These intermediaries provide flexible electrical connectivity while allowing the pixel definition layer to act as a stress-absorbing buffer, preventing direct stress transmission between cathode segments and improving overall cathode integrity.
3Reliability
If a compensation electrode structure is added to improve strength, then bending-resistance and impact-resistance are enhanced, but the device complexity increases
Solution Approach 1:
The compensation electrodes serve multiple functions: they provide electrical connectivity between segmented cathode electrodes, act as stress distribution elements during bending, and maintain structural integrity through the three-dimensional mesh network. This multi-functionality allows the added structural elements to justify their presence by delivering multiple benefits simultaneously.
Solution Approach 2:
The pixel definition layer serves as a flexible thin film that covers the compensation electrodes and provides mechanical protection while allowing bending. This thin film structure enables the device to achieve flexibility and bending resistance without requiring thick rigid protective layers, thereby limiting the increase in device complexity.
Data Source
AI summary
The present disclosure provides display panels and methods for manufacturing the same. The display panel includes a pixel definition layer, a cathode, and a compensation electrode. The pixel definition layer defines a plurality of pixel definition openings and a spacing region located between two adjacent pixel definition openings of the plurality of pixel definition openings. The cathode covers the pixel definition layer. The compensation electrode is located in the spacing region. The pixel definition layer covers the compensation electrode and defines a contact hole, the cathode and the compensation electrode are connected via the contact hole.