AlGaInP LED Strain Adjustment Layer for Plant Growth
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Solution Overview
Problem
Conventional red light emitting diodes with emission wavelengths around 660 nm struggle to achieve high output, efficiency, and monochromaticity, especially for plant growth applications, where longer wavelengths can inhibit growth and require high-speed response speeds, and existing techniques fail to extend emission wavelengths beyond 655 nm effectively.
Innovation Solution
A light emitting diode with a strained light emitting layer composed of AlGaInP, where the composition is restricted to specific ranges (0≤X≤0.1 and 0.39≤Y≤0.45) to achieve an emission wavelength of 655 nm or greater, combined with a strain adjustment layer that is transparent and has a smaller lattice constant than the GaAs substrate to reduce strain fluctuations and enhance mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional AlGaAs-based LEDs are used for red light emission around 660 nm, then the emission wavelength is suitable for plant growth, but the light output and efficiency are insufficient
Solution Approach 1:
The patent changes the material composition parameters by using AlGaInP instead of conventional AlGaAs, and specifically controls the composition ratios (0≤X≤0.1 and 0.39≤Y≤0.45) to achieve both high light output and improved emission efficiency while maintaining the 655 nm or greater wavelength suitable for plant growth
Solution Approach 2:
The patent employs composite material AlGaInP which combines aluminum, gallium, indium, and phosphorus to create a light emitting layer that simultaneously achieves high light output, high efficiency, and appropriate emission wavelength, overcoming the limitations of single-material systems
2Productivity
If the emission wavelength is extended to 655 nm or greater for plant growth, then photosynthesis efficiency is improved, but conventional techniques cannot achieve this wavelength extension effectively
Solution Approach 1:
The patent achieves precise wavelength control at 655 nm or greater by carefully adjusting the composition parameters X and Y in AlGaInP, where X represents Al content (0≤X≤0.1) and Y represents Ga content (0.39≤Y≤0.45), enabling accurate wavelength tuning for optimal plant growth illumination
Solution Approach 2:
The patent applies local quality optimization by creating a light emitting layer with specific compositional gradients and uniformity control, ensuring that the emission wavelength is consistently 655 nm or greater across the entire device area, which is critical for effective plant growth illumination
3Speed
If high-speed response is required for plant growth illumination, then the response speed must be improved, but conventional LEDs exhibit slower response characteristics
Solution Approach 1:
The patent improves response speed by optimizing the material composition and layer structure of AlGaInP, reducing carrier recombination time while maintaining stable light output through controlled composition ratios and appropriate layer thicknesses
4Loss of energy
If a quantum well structure is used to improve light emission, then emission efficiency increases, but the emission wavelength is shortened which is unsuitable for plant growth applications
Solution Approach 1:
The patent overcomes the wavelength shortening effect of quantum well structures by carefully selecting and controlling the composition parameters of AlGaInP, specifically maintaining higher Ga content (Y≥0.39) and controlled Al content (X≤0.1) to ensure the emission wavelength remains 655 nm or greater while still benefiting from quantum well emission efficiency
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 results in a light emitting diode with improved emission efficiency, monochromaticity, and fast response speed, achieving an emission wavelength of 655 nm or greater, with light emission efficiency approximately 4 times that of conventional AlGaAs-based LEDs, suitable for plant growth illumination.
Implementation Method 1
A light emitting diode with a strained light emitting layer composed of AlGaInP, where the composition is restricted to specific ranges (0≤X≤0.1 and 0.39≤Y≤0.45) to achieve an emission wavelength of 655 nm or greater
Implementation Method 2
combined with a strain adjustment layer that is transparent and has a smaller lattice constant than the GaAs substrate to reduce strain fluctuations and enhance mechanical strength
Data Source
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AI summary
A light emitting diode including a compound semiconductor layer having at least a pn junction-type light emitting unit and a strain adjustment layer stacked on the light emitting unit, wherein the light emitting unit has a stacked structure containing a strained light emitting layer having a composition formula of (AlXGa1-X)YIn1-YP (wherein X and Y are numerical values that satisfy 0≤X≤0.1 and 0.39≤Y≤0.45 respectively) and a barrier layer, and the strain adjustment layer is transparent to the emission wavelength and has a lattice constant that is smaller than the lattice constants of the strained light emitting layer and the barrier layer. The light emitting diode has an emission wavelength of not less than 655 nm, exhibits excellent monochromaticity, high output and/or high efficiency, and has a fast response speed.