Multi-Region LED Structure for Phosphor-Free White Light
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Solution Overview
Problem
Existing nitride semiconductor light emitting diodes (LEDs) are limited to emitting single-peak monochromatic light, making it difficult to produce mixed-color light, such as white light, which is necessary for applications like emotional lighting and general lighting that requires control of color temperature and luminance.
Innovation Solution
A light emitting device with multiple light emission regions, each emitting light of different peak wavelengths, connected in series or parallel, and optionally stacked with an intermediate layer, to achieve a desired color coordinate by combining light from these regions without using phosphors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single-peak monochromatic light emitting diode is used, then internal quantum efficiency is improved and light absorption losses are reduced, but the ability to produce mixed-color light such as white light is lost
Solution Approach 1:
The light emitting diode is divided into multiple light emission regions (first light emission region and second light emission region) with different areas, where each region emits light of a specific wavelength. This segmentation allows the device to produce multiple wavelengths simultaneously without requiring phosphor conversion, thus maintaining high internal quantum efficiency while achieving mixed-color light output.
Solution Approach 2:
Different regions of the light emitting diode are designed with different local properties - specifically, different emission wavelengths are generated in different spatial regions. The first light emission region and second light emission region have different areas and emit different wavelengths, creating local quality variations that enable mixed-color light production while avoiding phosphor-related energy losses.
2Adaptability or versatility
If multiple light emitting diodes emitting different monochromatic lights are combined or phosphor is used to implement white light, then mixed-color light is achieved, but device complexity increases
Solution Approach 1:
Multiple light emission regions with different emission characteristics are merged into a single integrated light emitting diode structure. The first and second light emission regions are formed within the same device, sharing common structural elements such as the substrate, electrode structures, and encapsulation, thereby achieving mixed-color light output without the complexity of multiple separate LED components or phosphor conversion systems.
Solution Approach 2:
The light emitting diode structure is designed to perform multiple functions simultaneously - it generates multiple wavelengths of light (blue and green/orange) within a single device structure. This multi-functionality eliminates the need for separate LEDs or phosphor materials, reducing overall system complexity while maintaining the capability to produce white light with adjustable color temperature.
3Adaptability or versatility
If multiple light emitting regions with different areas are used to emit different wavelengths, then mixed-color light is produced, but manufacturing precision requirements increase
Solution Approach 1:
The invention controls the emission characteristics by changing geometric parameters - specifically, the area ratio between the first light emission region and the second light emission region. By adjusting these area parameters during manufacturing, the intensity ratio of different wavelengths can be controlled, enabling color temperature adjustment while using standard fabrication processes for nitride semiconductor LEDs.
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 device efficiently produces white light by mixing light of different peak wavelengths, allowing for adjustable color temperature and luminance control without the need for phosphor conversion, enhancing lighting flexibility and efficiency.
Implementation Method 1
a light emitting device according to an exemplary embodiment of the present disclosure includes a first light emission region and a second light emission region. The first and second light emission regions include a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active region formed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer
Data Source
AI summary
A light emitting device according to an exemplary embodiment includes a first light emission region and a second light emission region. The first and second light emission regions include a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active region formed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer, respectively, an area of the first light emission region is larger than an area of the second emission region, and at least one of the first emission region or the second emission region emits light of a plurality of peak wavelengths.