OLED Substrate Support Layer for Crack Prevention
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Solution Overview
Problem
Inorganic insulation substrates used in organic light emitting diode display devices are prone to damage due to their low flexibility, and the fabrication process is complicated by height differences between display and non-display areas, which can lead to cracking or breaking during the formation of protective films.
Innovation Solution
A support layer made of opaque organic insulation material is disposed in the non-display area to uniformly support the inorganic insulation substrate, ensuring even pressure distribution and eliminating height differences, thereby preventing damage and simplifying the fabrication process by omitting the need for an opaque insulation material layer on the rear surface of the cover substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inorganic insulation substrate is used to improve the stability of thin film transistors, then the properties of components are improved, but the substrate is easily cracked or broken due to its low flexibility
Solution Approach 1:
The substrate is divided into two functional areas: the display area where the inorganic insulation substrate provides stability for thin film transistors, and the non-display area where a support layer made of flexible organic insulation material is added to provide flexibility and prevent cracking. This segmentation allows each area to have the properties needed for its specific function.
Solution Approach 2:
Different regions of the substrate are assigned different material properties: the display area uses inorganic insulation substrate for stability, while the non-display area uses flexible organic insulation material for bendability. This local differentiation resolves the contradiction by ensuring each area has the optimal properties for its purpose.
2Strength
If a support layer is added to the non-display area to prevent substrate damage, then the flexibility is improved, but height differences between display and non-display areas cause cracking during fabrication
Solution Approach 1:
The support layer in the non-display area is designed to extend to the same height as the display area, creating a uniform surface profile across the entire substrate. This equipotential design ensures that during roll laminating fabrication, there are no height differences that would cause cracking or damage to the inorganic insulation substrate.
3Object-affected harmful factors
If an opaque insulation material layer is formed on the rear surface of cover substrate to shield non-display area, then the shielding function is improved, but the fabrication procedure becomes more complex
Solution Approach 1:
The support layer made of opaque organic insulation material serves dual functions: it provides mechanical support to prevent substrate cracking in the non-display area, and simultaneously acts as the shielding layer to block light from reaching the non-display area. By merging these two functions into a single layer, the fabrication procedure is simplified as no separate opaque insulation material layer needs to be formed on the cover substrate rear surface.
Data Source
AI summary
An organic light emitting display device includes a substrate having a display area and a non-display area, an organic light emitting element and a sealing layer sequentially stacked on one side of the substrate in the display area, a support layer on the one side of the substrate in the non-display area, and a polarizing plate on the support layer in the non-display area and on the sealing layer in the display area, the polarizing plate covering an entirety of the support layer.