Flexible OLED Adhesive Layer for Narrow Bezel Stress Management
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Solution Overview
Problem
Organic light emitting display devices face stress and damage to wiring lines when bent, leading to malfunction, due to the brittleness of insulating layers and metal wiring, which also results in increased manufacturing costs and complexity.
Innovation Solution
An organic light emitting display device with a flexible substrate, an adhesive layer that extends to the bending area to minimize stress on wiring lines, and the removal of a barrier film to reduce thickness and manufacturing processes, thereby reducing stress and damage to wiring lines and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the substrate is bent to reduce bezel size, then the display device achieves narrow bezel or bezel-free design, but stress is intensively generated in wiring lines causing cracks and malfunction
Solution Approach 1:
The patent applies flexible shells and thin films by using a flexible encapsulation layer that can bend without cracking, replacing rigid protective layers. This allows the substrate to be bent for narrow bezel design while the flexible encapsulation layer absorbs the bending stress, preventing wiring line cracks and maintaining reliability.
Solution Approach 2:
The patent uses composite materials by combining flexible substrate materials with flexible encapsulation layers having specific mechanical properties. This composite structure distributes bending stress across different layers, protecting wiring lines from intensive stress while enabling the desired bent shape for narrow bezel.
2Shape
If the substrate is bent to reduce bezel size, then the display device achieves narrow bezel or bezel-free design, but insulating layers crack due to brittleness
Solution Approach 1:
The patent replaces brittle insulating layers with flexible encapsulation layers that can bend without cracking. These flexible thin films maintain the necessary insulation properties while accommodating the bending required for narrow bezel design, preventing crack propagation to wiring lines.
Solution Approach 2:
The patent changes the material parameters of the encapsulation layer to achieve flexibility. By selecting materials with appropriate Young's modulus and thickness, the encapsulation layer can bend with the substrate without generating excessive stress, thereby preventing cracks in the insulating structure.
3Length of moving object
If a barrier film is removed to reduce thickness, then the display device achieves thin thickness, but manufacturing complexity increases
Solution Approach 1:
The patent merges the functions of the barrier film and the encapsulation layer. By integrating the barrier function into the flexible encapsulation layer, the device achieves thin thickness without requiring a separate barrier film, thereby simplifying the manufacturing process rather than increasing complexity.
Solution Approach 2:
The flexible encapsulation layer serves multiple functions: it provides mechanical flexibility for bending, acts as a barrier to moisture and oxygen, and protects the wiring lines. This multi-functionality eliminates the need for separate barrier films and protective layers, reducing overall device thickness and simplifying manufacturing.
4Reliability
If separate protective layers are added to protect wiring lines in bending area, then wiring line reliability is improved, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent merges the protective function with the encapsulation layer that is already required for device sealing and flexibility. By integrating wiring line protection into the flexible encapsulation layer, no additional separate protective layers are needed, maintaining manufacturing simplicity while ensuring reliability.
Solution Approach 2:
The flexible encapsulation layer performs multiple protective functions simultaneously: it protects wiring lines from bending stress, provides environmental barrier, and maintains device flexibility. This multi-functionality eliminates the need for additional dedicated protective layers, reducing manufacturing complexity and cost.
Data Source
AI summary
An organic light emitting display device according to an exemplary embodiment of the present disclosure includes a flexible substrate, an adhesive layer, a pad unit, and a module. The flexible substrate includes a display area in which a display unit is disposed, a first non-display area which encloses the display area, a bending area which extends from the first non-display area, and a second non-display area which extends from one side of the bending area. The adhesive layer is disposed on the display unit. The pad unit is disposed in the second non-display area of the flexible substrate. The module is connected to be in contact with the pad unit. In this case, the adhesive layer extends from the display area to the bending area to cover at least a part of the bending area of the flexible substrate.