Nitride Semiconductor Light Emitting Device With Nano LED Array
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light emitting diodes (LEDs) face efficiency issues in producing white light without using fluorescent materials, particularly due to lattice mismatch and reduced light emission efficiency as the wavelength increases.
Innovation Solution
A light emitting device comprising a semiconductor light emitting diode with a nano light emitting diode array, featuring nitride semiconductor layers and active layers with InGaN quantum well structures, allowing for the emission of blue light and a complementary wavelength to produce white or pseudo-white light without fluorescent materials, utilizing nanorod, nano-pyramid, or core-shell nanorod structures to enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If InGaN layer with increased In content is used to emit longer wavelength light, then the emitted color shifts to longer wavelength, but lattice mismatch increases and light emission efficiency deteriorates
Solution Approach 1:
The device segments the light emission function into two independent parts: a first active layer emitting blue light (short wavelength) and a second active layer emitting green or yellow light (longer wavelength). Each layer is optimized for its specific wavelength range, avoiding the lattice mismatch problem that occurs when trying to emit longer wavelengths from a single InGaN layer. This segmentation allows both layers to operate at high efficiency while producing combined white or pseudo-white light.
2Illumination intensity
If fluorescent materials are used to produce white light, then white light can be obtained, but the device complexity and manufacturing cost increase
Solution Approach 1:
The invention extracts and eliminates the fluorescent material component from the white light generation system. Instead of using a blue LED with fluorescent phosphor coating, the patent uses two separate light-emitting diode structures with different active layers that directly emit light at different wavelengths. These lights combine to produce white or pseudo-white light, removing the need for fluorescent materials and simplifying the overall device structure.
Solution Approach 2:
The second active layer serves multiple functions: it emits green or yellow light to complement the blue light for white light production, and it can be independently controlled to adjust color coordinates. This multi-functionality allows the device to achieve white light output without fluorescent materials while providing additional control capabilities.
3Reliability
If nano light emitting diode array is added to semiconductor light emitting diode, then internal quantum efficiency and optical extraction efficiency are improved, but device complexity increases
Solution Approach 1:
The nano light emitting diode array is nested on top of the semiconductor light emitting diode, forming a hierarchical structure where the nano-LEDs are positioned to receive and utilize the light from the underlying semiconductor LED. This nesting arrangement improves optical extraction efficiency by providing additional light-emitting surfaces and reducing total internal reflection, while the modular nano-LED structure allows for scalable implementation that balances performance improvement with manufacturing 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 enables the production of white or pseudo-white light with improved internal quantum efficiency and optical extraction efficiency, simplifying manufacturing and reducing costs by eliminating the need for fluorescent materials and allowing real-time color coordinate control.
Implementation Method 1
a second active layer between the third and fourth nitride semiconductor layers... configured to emit light of a wavelength that is mixed with the blue light to produce white light
Data Source
AI summary
A light emitting device may include a semiconductor light emitting diode which may include a first nitride semiconductor layer doped as an n-type, a second nitride semiconductor layer doped as a p-type, and a first active layer provided between the first and second nitride semiconductor layers, and a nano light emitting diode array in which a plurality of nano light emitting diodes may be arranged on the semiconductor light emitting diode so as to be separated from each other.