Multiple Quantum Well LED for Plant-Matched Blue-Violet Spectrum
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Solution Overview
Problem
Existing plant illumination technologies lack the ability to precisely control light-emitting diodes (LEDs) to emit light within a specific band in the spectrum to promote light energy absorption by plants, which is crucial for healthy growth.
Innovation Solution
A light-emitting diode with a multiple quantum well structure that generates a broadband blue-violet light spectrum, matching the photosynthetic action spectrum of plants, by using a specific design of indium gallium nitride well layers and aluminum gallium nitride barrier layers, achieving higher photosynthetic photon flux (PPF) and photosynthetic photon efficacy (PPE).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional single-peak LED structures are used for plant illumination, then the device complexity is low, but the photosynthetic photon efficacy is insufficient because the light spectrum does not match the photosynthetic action spectrum of plants
Solution Approach 1:
The LED structure is segmented into multiple quantum well layers with different indium concentrations (InGaN wells with x=0.15, 0.20, 0.25 respectively), where each layer emits at a different wavelength. This segmentation creates a multi-peak broadband spectrum that matches the photosynthetic action spectrum, resolving the contradiction between maintaining simple device structure and achieving high photosynthetic photon efficacy.
Solution Approach 2:
The patent uses composite material structures combining InGaN quantum well layers with different indium concentrations embedded in GaN barrier layers. This composite approach enables the emission of multiple wavelengths (blue-violet region with peaks at different wavelengths) from a single LED device, improving photosynthetic photon efficacy without requiring multiple separate LED chips.
2Adaptability or versatility
If the indium concentration in quantum well layers is increased to broaden the emission spectrum, then the broadband light output is improved, but the manufacturing precision control becomes more difficult due to varying indium concentrations across layers
Solution Approach 1:
Each quantum well layer is assigned a specific indium concentration (0.15, 0.20, 0.25) tailored to emit at a particular wavelength range. This local quality approach allows precise control of the emission spectrum by optimizing the indium concentration in each specific layer, achieving broadband coverage while maintaining manufacturability through standardized growth parameters for each layer type.
Solution Approach 2:
The patent systematically varies the indium concentration parameter across different quantum well layers to tune the emission wavelengths. By changing this single parameter (indium concentration) in a controlled manner from layer to layer, the patent achieves broadband spectrum emission while maintaining consistent manufacturing processes, thus resolving the contradiction between spectrum coverage and manufacturing precision.
3Productivity
If multiple quantum well layers with different indium concentrations are used to achieve multi-peak emission, then the photosynthetic photon flux is enhanced, but the energy loss increases due to non-radiative recombination in high indium concentration layers
Solution Approach 1:
The patent optimizes the thickness and composition of barrier layers between quantum wells to dynamically control carrier confinement and transport. By adjusting barrier layer parameters, the patent enhances radiative recombination in high-indium-concentration layers while suppressing non-radiative recombination, thus maintaining high photosynthetic photon flux with reduced energy loss.
Solution Approach 2:
The GaN barrier layers act as intermediaries between InGaN quantum well layers with different indium concentrations. These barrier layers facilitate efficient carrier injection into the quantum wells while preventing carrier leakage and reducing non-radiative recombination at interfaces, thereby enabling high photosynthetic photon flux generation with minimized energy loss in high-indium-concentration layers.
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 LED emits a light beam with a broadband blue-violet spectrum that closely matches the absorption spectrum of chlorophyll a, providing higher PPF and PPE, thereby enhancing light energy absorption by plants.
Implementation Method 1
a light-emitting diode with a multiple quantum well structure is designed to generate a broadband blue-violet light spectrum
Implementation Method 2
matches the absorption spectrum of chlorophyll a, achieving high photosynthetic photon efficacy and flux
Data Source
AI summary
A light-emitting diode for plant illumination is provided. The light-emitting diode has a multiple quantum well structure for generating a light beam with a broadband blue-violet light spectrum. The broadband blue-violet light spectrum has a first peak and a second peak within a range from 410 nm to 450 nm, a wavelength value of the second peak is greater than a wavelength value of the first peak, and a difference between the wavelength value of the second peak and the wavelength value of the first peak ranges from 5 nm to 30 nm. The broadband blue-violet light spectrum generated by the light-emitting diode can better match a photosynthetic action spectrum of plants.