LED Light Extraction via Insulating Layer and Transmission Electrode
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Solution Overview
Problem
Conventional light emitting diodes (LEDs) experience significant light loss due to the absorption of light by opaque metallic electrodes, leading to reduced efficiency in light emission.
Innovation Solution
A novel LED structure is introduced, featuring a light emitting structure with a superlattice layer and an insulating layer that reduces light absorption by spreading current and minimizing the contact area with the second electrode, combined with a light transmission electrode layer to enhance light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If opaque metallic electrodes are used in conventional LEDs, then electrical connection is achieved, but light loss occurs due to light absorption by the electrodes
Solution Approach 1:
An insulating layer with light-transmitting properties is introduced as an intermediary between the opaque metallic second electrode and the light emitting structure. This insulating layer allows electrical isolation while permitting light to pass through, thereby reducing light absorption by the electrode and improving light extraction efficiency without compromising electrical connection reliability
Solution Approach 2:
The patent applies different material properties to different regions: the insulating layer is positioned specifically where light extraction is critical, having both insulating properties for electrical isolation and light-transmitting properties for optical performance. This localized application of specific material qualities resolves the contradiction between electrical connection and light transmission
2Loss of energy
If the second electrode contacts the light emitting structure directly, then electrical connection is established, but light absorption by the electrode increases
Solution Approach 1:
The insulating layer serves as a mediator that reduces direct contact between the second electrode and the light emitting structure. By positioning this layer between them, light absorption by the electrode is minimized while the structural complexity increase is offset by the simplicity of the layering approach and manufacturing process
3Loss of energy
If current is concentrated in a small area, then electrical efficiency is improved, but light loss increases due to electrode absorption
Solution Approach 1:
The insulating layer extends in the vertical dimension between the electrode and light emitting structure, creating a new spatial dimension for light transmission. This dimensional approach allows current to remain concentrated for electrical efficiency while light travels through the insulating layer in another dimension, reducing absorption losses
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 minimizes light loss and improves light emitting efficiency by reducing the amount of light absorbed by the second electrode and increasing light generation from other regions of the active layer.
Implementation Method 1
A light emitting diode (LED) includes a p-n junction diode having a characteristic of converting electric energy into light energy
Implementation Method 2
an insulating layer extending from a lower portion of the second electrode to an upper portion of the second conductivity type semiconductor layer, wherein the lateral side of the insulating layer contacts with the superlattice structure layer
Data Source
Figure 1~2
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AI summary
A light emitting diode according to the embodiment includes a light emitting structure (145) including a first conductive semiconductor layer (130), an active layer (140) on the first conductive semiconductor layer, a second conductive semiconductor layer (150) on the active layer, a superlattice structure layer (160) on the second conductive semiconductor layer, and a third conductive semiconductor layer (170) on the superlattice structure layer; a light transmission electrode layer (190) on the light emitting structure; a first electrode (180) connected to the first conductive semiconductor layer; a second electrode (195) electrically connected to the light transmission electrode layer on the light emitting structure; and an insulating layer (120) extending from a lower portion of the second electrode to an upper portion of the second conductive semiconductor layer.