Display Device High Refractive Index Member Light Direction
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Solution Overview
Problem
Conventional display devices suffer from inefficient light emission due to radial light production and lack of light directionality, leading to reduced efficiency, and organic materials in these devices are prone to degradation from outgassing, which compromises reliability.
Innovation Solution
The implementation of a display device structure featuring a high refractive index member, a low refractive index member, and a capping member, where the high refractive index member is positioned between the low refractive index member and the emission layer, and the capping member surrounds the high refractive index member, directing light vertically and preventing outgassing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If light is emitted radially from the emission element, then the light can be emitted in all directions, but the emission efficiency is reduced because light leaves at angles where users can't see it
Solution Approach 1:
The patent changes the refractive index parameter by introducing a high refractive index member (refractive index > 1.5) between the emission layer and the upper structure. This parameter change redirects light rays that would otherwise escape at oblique angles to travel more vertically, increasing the proportion of visible light and improving emission efficiency.
Solution Approach 2:
The high refractive index member acts as an intermediary optical element between the emission layer and the upper structure (encapsulation substrate, polarizing plate, or window). This intermediary component modifies the light path by refraction, directing light vertically to improve visibility and reduce energy loss.
2Reliability
If layers above the emission layer are disposed directly on the emission layer, then the structure is simplified, but material offgassing from these layers degrades the emission layer and reduces reliability
Solution Approach 1:
The high refractive index member serves as a physical barrier and intermediary layer between the emission layer and the upper structure layers. This intermediary structure prevents direct contact and material exchange, blocking offgassed materials from reaching and degrading the emission layer, thereby improving reliability without significantly increasing overall structural complexity.
Solution Approach 2:
The patent segments the device structure by introducing a distinct high refractive index member layer that separates the emission layer from the upper structure layers. This segmentation creates a protective barrier zone that prevents harmful material interactions while maintaining the functional integrity of each layer.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances light emission efficiency by directing light vertically and reduces damage to the emission layer, thereby increasing the reliability and efficiency of the display device.
Implementation Method 1
a high refractive index member disposed on the second electrode, overlapping the emission layer, and having a first refractive index, a low refractive index member disposed between the high refractive index member and the emission layer and having a second refractive index smaller than the first refractive index
Data Source
AI summary
A display device includes a first substrate, a first electrode disposed on the first substrate, an emission layer disposed on the first electrode, a second electrode disposed on the emission layer, a high refractive index member disposed on the second electrode, overlapping the emission layer, and having a first refractive index, a low refractive index member disposed between the high refractive index member and the emission layer and having a second refractive index smaller than the first refractive index, a capping member disposed between the low refractive index member and the emission layer, and a second substrate overlapping at least a portion of the first substrate and disposed on the high refractive index member.