Multi-Layer Organic Stack for Flexible Display Wiring Protection
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Solution Overview
Problem
Display apparatuses face challenges in maintaining effective interlayer adhesion and protecting wirings, especially in non-display areas, particularly when subjected to bending, which can lead to damage and reduced functionality.
Innovation Solution
The display apparatus incorporates a substrate with a display area and a non-display area that includes a bending section, featuring a connection wiring, an inorganic protective layer covering the wirings, and an upper organic layer with a specific stacking configuration of first, second, and third upper organic layers to enhance adhesion and protection, along with an inorganic insulating layer and organic layers to support the structure and prevent damage during bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple single-layer organic structure is used, then manufacturing is easier, but interlayer adhesion deteriorates and wiring protection is insufficient
Solution Approach 1:
The organic layer is segmented into multiple distinct layers (first organic layer, second organic layer, third organic layer) with different materials and functions. Each layer serves specific purposes: the first organic layer provides adhesion to the inorganic protective layer, the second organic layer offers flexibility for bending, and the third organic layer provides additional protection. This segmentation resolves the contradiction by achieving both good adhesion and flexibility through specialized layers rather than a single homogeneous layer.
Solution Approach 2:
The patent employs composite material structure by combining different organic materials (e.g., acrylic-based, polyimide-based, cyclic carbonate-based polymers) in a multi-layer configuration. Each material is selected for its specific properties: adhesion promotion, bendability, or protective characteristics. This composite approach enables the structure to simultaneously achieve strong interlayer adhesion and resistance to bending-induced damage.
2Adaptability or versatility
If the display apparatus is made thinner and more flexible, then adaptability to various technical fields improves, but wiring protection and structural integrity deteriorate
Solution Approach 1:
The patent incorporates a second organic layer with high flexibility (e.g., polyimide-based polymer) that acts as a flexible protective film over the wirings. This flexible layer allows the display apparatus to be bent and adapted to various shapes while maintaining wiring integrity. The flexible film absorbs bending stress and prevents crack propagation to the underlying connection wirings, thus resolving the contradiction between flexibility and wiring protection.
Solution Approach 2:
The multi-layer organic structure provides beforehand cushioning to the connection wirings by absorbing and distributing mechanical stress before it reaches the wirings. The different materials in the organic layers are selected to provide shock absorption and stress distribution capabilities, protecting the wirings from damage during bending operations before actual contact or excessive stress occurs.
3Reliability
If a thick inorganic protective layer is used, then wiring protection improves, but bending flexibility and stress distribution deteriorate
Solution Approach 1:
The patent applies local quality by having the inorganic protective layer selectively cover only critical wiring areas rather than uniformly covering the entire display area. The inorganic protective layer is positioned specifically where wiring protection is most needed, while other areas maintain flexibility. This localized approach allows strong protection where required without compromising overall bending flexibility.
Solution Approach 2:
The patent creates a composite structure combining inorganic protective layers with multiple organic layers having different mechanical properties. The organic layers, particularly the flexible second organic layer, compensate for the rigidity of the inorganic protective layer by providing stress distribution and bendability. This composite material system resolves the contradiction by combining the protective qualities of inorganic materials with the flexibility of organic materials in a coordinated multi-layer structure.
Data Source
AI summary
A display apparatus includes: a substrate including a display area and a non-display area surrounding the display area; a data wiring on the substrate in the display area; a connection wiring on the substrate in the non-display area and including a same material as the data line; an inorganic protective layer on the substrate covering the data line and extending to the non-display area; and an upper organic layer on the substrate covering the connection wiring and at least a portion of the inorganic protection layer, where the upper organic layer includes a first to third upper organic layers, and the second upper organic layer in a side of the upper organic layer adjacent to the display area is in direct contact with the inorganic protective layer, and the third upper organic layer exposes an end of the second upper organic layer in the side of the upper organic layer.