Display Device Insulating Layer Crack Prevention
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Solution Overview
Problem
Display devices with through portions are prone to cracking during manufacturing, which can propagate and damage the surrounding pixel array, due to stress and particle accumulation in the recesses formed during the creation of these features.
Innovation Solution
A display device design that includes a substrate with a through portion surrounded by a pixel array, featuring a pattern portion with a recess concave along the insulating layer's thickness direction, covered by a cladding layer made of organic material, and an inorganic encapsulation layer that directly contacts the insulating layer, preventing crack propagation and particle accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a through portion is formed in the substrate and insulating layer, then the display device achieves a slim profile and diversified use, but stress accumulates in the surrounding insulating layer causing crack propagation that damages the pixel array
Solution Approach 1:
The insulating layer is segmented into two distinct layers: a first insulating layer directly surrounding the through portion and a second insulating layer above it. This segmentation allows the first layer to absorb stress from the through portion while the second layer maintains structural integrity, preventing crack propagation to the pixel array.
Solution Approach 2:
The first insulating layer has different properties (lower refractive index, different material composition) compared to the second insulating layer. This local quality difference enables the first layer to specifically address stress concentration at the through portion while the second layer provides overall structural support and optical uniformity.
2Ease of manufacture
If recesses are formed during through portion creation, then the through portion can be manufactured, but particles accumulate in the recesses causing display defects
Solution Approach 1:
The recesses in the first insulating layer are filled with a material having a different refractive index before the pixel array is manufactured. This preliminary action prevents particle accumulation by eliminating empty spaces where particles could settle, while still allowing the through portion to be formed subsequently.
Solution Approach 2:
A material with different refractive index properties acts as an intermediary substance filling the recesses. This intermediary material prevents particle accumulation by providing a continuous medium that eliminates void spaces, while also managing optical effects at the through portion interface.
3Weight of stationary object
If the insulating layer is made thin to achieve slim profile, then the display device becomes lighter and thinner, but stress concentration increases causing cracks
Solution Approach 1:
The insulating layer is divided into two layers with the first layer being thinner and positioned at the stress-prone through portion area, while the second layer provides additional thickness and structural support above it. This segmentation maintains the slim overall profile while distributing stress more effectively.
Solution Approach 2:
The two insulating layers are made of different materials with different refractive indices and mechanical properties. This composite structure combines the advantages of both materials: the first layer provides stress management at the through portion, while the second layer provides structural integrity and optical uniformity, achieving both slimness and strength.
Data Source
AI summary
A display device includes: a substrate; an insulating layer arranged above the substrate; a through portion configured to pass through the substrate and the insulating layer; a pixel array located above the insulating layer and including pixels each including a light-emitting element including, a pixel electrode, an opposite electrode facing the pixel electrode, and an emission layer arranged between the pixel electrode and the opposite electrode, the pixels at least partially surrounding the through portion; and a pattern portion arranged between the through portion and the pixel array, wherein the pattern portion includes: a recess that is concave along a thickness direction of the insulating layer; and a cladding layer arranged above the insulating layer, configured to cover the recess, and including a material different from the insulating layer.