Tunable LED Grow Light System for Plant Spectral Optimization

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Solution Overview

Problem

Conventional grow lights fail to efficiently provide light wavelengths that match the specific energy absorption demands of plants, leading to suboptimal plant growth and unattractive lighting for humans, with limitations in spectral control, energy efficiency, and operation lifetime.

Innovation Solution

A lighting system featuring a controller and multiple light sources, including hyper-red, amber, and blue-white LEDs, that can adjust emission characteristics to optimize photosynthetic active radiation while maintaining a desirable color temperature and high color rendering index, using pulse modulation to minimize light saturation and adjust for varying plant needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional grow lights use blue and red LEDs to match plant absorption peaks, then photosynthetic efficiency is improved, but color rendering for human vision deteriorates (appears purple and unattractive)

Engineering Contradiction:
Improvephotosynthetic efficiencyVSAvoidcolor rendering quality
Core Design Contradiction:
ProductivityVSIllumination intensity

Solution Approach 1:

The lighting system segments the spectrum into multiple discrete wavelength bands (450nm blue, 530nm green, 630nm red, 660nm far-red) using separate LED modules, allowing independent optimization of each band for both plant photosynthesis and human visual perception

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the spectrum are assigned different quality characteristics: blue and red regions are optimized for plant absorption peaks while green and other regions are optimized for human color rendering, creating locally optimized spectral quality throughout the emission spectrum

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If conventional light sources (incandescent, fluorescent, metal halide) are used, then broad spectrum coverage is achieved, but electrical efficiency deteriorates (only 10-40% conversion to visible light)

Engineering Contradiction:
Improvespectral coverageVSAvoidelectrical to optical conversion efficiency
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The system extracts only the specific wavelength bands that are most effective for plant photosynthesis (blue 450nm, red 630nm, far-red 660nm) and human vision (green 530nm), eliminating wasteful emission at other wavelengths to achieve >50% electrical to optical conversion efficiency

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system changes the spectral parameters from broad-spectrum conventional sources to narrow-band targeted wavelengths, and changes the efficiency parameter by using LED technology with internal quantum efficiency >50%, achieving both full spectral control and high energy efficiency

Inventive Principle:
Principle #35Parameter changes

3Power

If conventional light sources are used, then initial light output is achieved, but operation lifetime deteriorates (1,000-24,000 hours)

Engineering Contradiction:
Improvelight outputVSAvoidoperation lifetime
Core Design Contradiction:
PowerVSDuration of action of stationary object

Solution Approach 1:

The system uses multiple individual LED modules that can be independently replaced, where each LED has long lifetime (>50,000 hours), and the modular design allows replacement of only failed modules rather than entire lighting systems

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Use of energy by moving object

If fixed spectrum LED arrays are used, then energy efficiency is improved, but adaptability to different plant species and growth stages deteriorates

Engineering Contradiction:
Improveenergy efficiencyVSAvoidspectral adaptability to plant needs
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The system dynamically adjusts the intensity of each wavelength band (450nm, 530nm, 630nm, 660nm) independently through controllable LED modules, allowing real-time adaptation to different plant species, growth stages, and environmental conditions while maintaining high energy efficiency

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The modular LED array with independent control of multiple wavelength bands serves multiple functions: supporting different plant species with different spectral requirements, accommodating various growth stages, providing both high photosynthetic efficiency and good color rendering, and enabling pulsed operation modes

Inventive Principle:
Principle #6Universality (Multi-functionality)

5Productivity

If continuous light emission is used, then constant photosynthesis stimulation is achieved, but light saturation and energy waste occur

Engineering Contradiction:
Improvephotosynthesis stimulationVSAvoidenergy waste from saturation
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The system uses periodic pulsed emission of light rather than continuous emission, synchronizing light delivery with plant photosynthetic cycles to stimulate photosynthesis during active periods while avoiding saturation and energy waste during rest periods

Inventive Principle:
Principle #19Periodic action

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 system achieves high photosynthetic efficiency, attractive color rendering, and extended operation lifetime by optimizing light emission to match plant absorption spectra and human visual sensitivity, providing superior plant growth and aesthetic appeal.

Implementation Method 1

The plurality of light sources has light emitting diodes in a ratio of about 6 hyper-red LEDs to 1 amber LEDs to 5 blue-white LEDs

Methodology Applied
Scientific EffectLight-emitting diode (LED): Light Emitting Diode

Implementation Method 2

The best AllnGaP red and AllnGaN green and blue HB-LEDs can have internal quantum efficiencies better than 50%

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 3

Promotion of plant growth using artificial light to augment or replace solar light has been the focus of significant research and experimentation

Methodology Applied
Scientific EffectPhotosynthesis: Photosynthesis

Implementation Method 4

The absorption spectra of many plants containing chlorophyll exhibit peak absorption in the wavelength ranges of about 410-490 nanometers ('blue light') and of about 590-650 nanometers ('red light')

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentEP2785171B1Illumination and grow light system
Publication Date: 2020.06.24 HEALTHE INC
  • EP2785171B1 patent drawingFigure 1~2
  • EP2785171B1 patent drawingFigure 3
  • EP2785171B1 patent drawingFigure 4

AI summary

An illumination and grow light system and associated methods are provided to produce an emission spectrum which may be optimized for plant response curve, as well as provide high quality light with respect to the human response curve. Embodiments of the present invention may include highly efficient tunable lamps and associated modulation controls that allow specific radiation wavelength bands to be manipulated, the emission direction and intensity to be varied, and the output power to be coordinated to create high fluxes of photosynthetic active radiation while maintaining a desirable color temperature and high color rendering index.