Through-Hole Display Encapsulation Structure for Crack Resistance
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Solution Overview
Problem
In organic EL display devices with through-holes for electronic components, moisture ingress through cracks in the inorganic encapsulation film around the through-hole leads to deterioration of the light-emitting function layers, causing display defects.
Innovation Solution
A display device with inversely tapered protruding portions surrounding the through-hole, comprising a resin substrate layer, inorganic insulating film, and a metal layer, which are separated by slits, and covered by an inorganic encapsulation film, to prevent crack propagation and moisture ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a through-hole is provided in the non-display region to install electronic components, then the functionality and versatility of the display device are improved, but cracks may occur in the inorganic encapsulation film around the through-hole due to processing and applied loads, allowing moisture ingress and deterioration of the light-emitting function layers
Solution Approach 1:
The inorganic insulating film is divided into multiple segments (first, second, and third inorganic insulating films) arranged in an inverted tapered manner around the through-hole. This segmentation allows each layer to independently manage stress and prevent crack propagation, while collectively providing comprehensive protection against moisture ingress through the through-hole region.
Solution Approach 2:
The protection structure extends from a two-dimensional planar configuration to a three-dimensional inverted tapered configuration. The inorganic insulating films are arranged in multiple layers with varying widths, creating a stepped structure that adds vertical dimensionality. This multi-layer arrangement provides enhanced crack resistance and moisture barrier properties compared to a single-layer structure.
2Manufacturing precision
If the inorganic insulating film is patterned to form an inversely tapered cross-sectional structure, then the common light-emitting function layer can be formed separately around the through-hole, but cracks may still occur and progress toward the display region
Solution Approach 1:
The inorganic insulating films are formed in an inverted tapered configuration before the encapsulation process. This preliminary structuring creates a built-in stress distribution pattern that prevents crack initiation and propagation during subsequent encapsulation and device operation. The wider base at the bottom provides a foundation that distributes mechanical loads, preventing cracks from forming during the encapsulation process.
Solution Approach 2:
The structure combines multiple inorganic insulating film layers with different dimensions and properties to create a composite protective barrier. The first, second, and third inorganic insulating films form a multi-material system that provides both mechanical strength to prevent cracks and chemical stability to resist moisture ingress, addressing both manufacturing precision and harmful factor resistance.
3Device complexity
If a single-layer inorganic insulating film is used, then the structure is simpler, but it cannot effectively prevent crack propagation to the display region
Solution Approach 1:
The inorganic insulating film is segmented into three distinct layers (first, second, and third inorganic insulating films) with progressively varying widths. This segmentation creates multiple interfaces that can absorb and distribute mechanical stress, preventing crack propagation. Each layer acts as an independent barrier, and the cumulative effect of all three layers provides superior crack resistance compared to a single-layer structure.
Solution Approach 2:
The transition from a single-layer to a multi-layer inverted tapered structure adds vertical dimensionality to the design. The stacked arrangement of inorganic insulating films creates a three-dimensional protective configuration that provides enhanced mechanical strength and crack resistance while maintaining a compact form factor suitable for display device integration.
Data Source
AI summary
A plurality of inversely tapered protruding portions are provided so as to surround a through-hole in a non-display region, each of the plurality of inversely tapered protruding portions includes a resin portion constituted by a resin substrate layer and separated by a plurality of substrate slits, and inorganic insulating layers provided on the resin portion, a first inorganic encapsulation film covers the plurality of inversely tapered protruding portions and the plurality of substrate slits, and a metal layer is provided on the inorganic insulating layer in at least one of the plurality of inversely tapered protruding portions.