Light-Emitting Device With Insulated Reflective Recesses
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Solution Overview
Problem
Conventional light-emitting devices face challenges with low light extraction efficiency due to absorption of light within the device and inefficient current spreading, leading to reduced optical output and increased operating voltage.
Innovation Solution
A light-emitting device structure featuring a reflective layer insulated from the light-emitting structure by an insulation layer, with recesses and connection electrodes to enhance light reflection and extraction, improving light extraction efficiency and optical output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light extraction path is lengthened in conventional light-emitting devices, then light extraction opportunity increases, but absorption inside the device increases and light extraction efficiency degrades
Solution Approach 1:
The patent introduces a reflective layer at the bottom of the light-emitting device to invert the conventional light extraction approach. Instead of relying solely on horizontal extraction paths, light that would normally be absorbed is reflected upward through the active layer, creating a second extraction opportunity and improving overall light extraction efficiency while reducing energy loss through absorption.
2Illumination intensity
If current spreading is concentrated at certain portions, then injection efficiency improves, but most emitted light is absorbed at the emission portion and light extraction efficiency degrades
Solution Approach 1:
The reflective layer is strategically positioned at the bottom region where current injection occurs but light extraction is limited. This local modification creates different light extraction qualities in different regions: the bottom region reflects light upward for extraction, while other regions maintain conventional extraction paths, thereby reducing energy loss at the emission portion without compromising injection efficiency.
3Illumination intensity
If reflective layer is added to enhance light reflection, then light extraction efficiency improves, but device complexity increases
Solution Approach 1:
The reflective layer serves multiple functions simultaneously: it reflects light upward to improve extraction efficiency, provides an additional current injection path through the transparent conductive layer, and creates a compact vertical structure that integrates multiple functionalities in a single layer, thereby improving performance without proportionally increasing device complexity.
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 solution significantly enhances light extraction efficiency and optical output while reducing operating voltage by effectively reflecting and directing light outward from the device.
Implementation Method 1
a reflective layer disposed inside the second recess... The reflective layer reflects light in an ultraviolet wavelength range
Data Source
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AI summary
Embodiments disclose a light-emitting device including a light-emitting structure including a first conductive semiconductor layer, a second conductive semiconductor layer, an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer, and a first recess and a second recess passing through the second conductive semiconductor layer and the active layer and disposed up to a partial region of the first conductive semiconductor layer, a connection electrode disposed inside the first recess and electrically connected to the first conductive semiconductor layer, a reflective layer disposed inside the second recess, and an insulation layer configured to electrically insulate the reflective layer and the light-emitting structure, and a light-emitting device package including the same.