Light-Emitting Device With Intermediate Layer for Transparent Interconnects
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Solution Overview
Problem
In light-emitting devices with transparent electrodes, the refractive index differences between the insulating layer and the electrode lead to conspicuous edges when viewed from the opposite side of the transparent substrate, also reducing light extraction efficiency.
Innovation Solution
A light-emitting device configuration that includes a light-transmitting substrate, a light-transmitting interconnect, an insulating layer, and an intermediate layer with a refractive index between the interconnect and the insulating layer, which reduces edge visibility and enhances light extraction efficiency by minimizing refractive index mismatches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If transparent electrodes are used to make the light-emitting device transparent, then the device transparency is improved, but the electrode edges become conspicuous due to refractive index differences
Solution Approach 1:
An intermediate layer with refractive index n3 is introduced between the transparent electrode (refractive index n2) and the insulating layer (refractive index n1), where n1 < n3 < n2. This intermediate layer acts as a refractive index bridge, gradually transitioning the optical properties between the two layers and reducing the abrupt refractive index mismatch that causes edge visibility. The intermediate layer is positioned to cover the electrode edge region, effectively masking the conspicuous edges while maintaining device transparency.
2Illumination intensity
If transparent electrodes with different refractive indexes are used, then device transparency is achieved, but light extraction efficiency is reduced due to refractive index mismatch
Solution Approach 1:
The refractive index parameter is optimized by introducing an intermediate layer with a specific refractive index value (n3) that lies between the electrode refractive index (n2) and the insulating layer refractive index (n1). This parameter optimization reduces the refractive index contrast at the interface, minimizing light reflection and maximizing light extraction efficiency. The intermediate layer's refractive index is specifically selected to achieve optimal optical coupling between the electrode and insulating 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
The intermediate layer effectively reduces the visibility of electrode edges and improves light extraction efficiency by matching refractive indices, making the device more transparent and efficient.
Implementation Method 1
a refractive index of the intermediate layer is between a refractive index of the interconnect and a refractive index of the insulating layer
Data Source
AI summary
A light-emitting device includes a light-transmitting substrate, a light-transmitting interconnect located over the substrate, an insulating layer located over the substrate and the interconnect, and an intermediate layer formed in at least a region of a lateral side of the interconnect that overlaps the insulating layer.