Fiber-Optic Sheet Lighting for Controlled Horticulture
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current horticultural luminaires lack precise control over spectral power, spatial, and temporal distributions of optical radiation, limiting their ability to optimize plant growth and health in controlled environments, and they face challenges with heat management, LED packaging, and fixed spectral power distributions.
Innovation Solution
A horticultural lighting system utilizing a linear array of optical elements optically coupled via fiber optic cables to laser light sources, housed within a hollow linear optic with a holographic diffuser, allowing for precise control of laser wavelengths and light intensity to maximize photosynthesis and photomorphogenesis responses, and incorporating laser modules with diffractive optics and dichroic mirrors to generate composite monochromatic radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional HPS or MH arc lamps are used to provide sufficient optical radiation for plant photosynthesis, then plants receive adequate light for growth, but the luminaires must be positioned several meters above the plant canopy to avoid overheating the plant leaves and flowers due to large amounts of infrared radiation and conductive heat
Solution Approach 1:
The invention segments the light spectrum by using multiple LED chips with different peak wavelengths (blue, cyan, green, yellow-green, yellow, orange, red) to generate a tailored spectral power distribution. This segmentation allows selective emission of photosynthetically active radiation while minimizing infrared and heat-generating wavelengths, enabling close positioning of luminaires to plant canopies without overheating.
Solution Approach 2:
The invention changes the spectral parameters by using LED chips with specifically selected peak wavelengths and bandwidths to create a custom spectral power distribution optimized for plant photosynthesis and photomorphogenesis. This parameter optimization allows high photosynthetic photon flux density to be delivered at close distances without excessive heat radiation to the plants.
2Illumination intensity
If HPS and MH lamps are used to provide overhead lighting, then spatially even photosynthetic photon flux density can be achieved, but the spectral power distributions are fixed and cannot be dimmed
Solution Approach 1:
The invention introduces dynamic control by making the spectral power distribution and intensity adjustable through independent control of multiple LED channels. The system can vary the relative intensities of different wavelength components to match changing plant needs during different growth stages, and can be dimmed or brightened as required, providing adaptability that fixed HPS and MH lamps cannot achieve.
Solution Approach 2:
The invention creates a multi-functional luminaire that can serve multiple purposes: providing photosynthetically active radiation, controlling photomorphogenesis, adjusting spectral composition for different growth stages, and varying intensity levels. This universal design replaces the need for multiple fixed-function lamps by integrating spectrum control and intensity adjustment into a single system.
3Temperature
If linear fluorescent lamps are used to position within centimeters of the plant canopy, then heat issues are avoided, but each lamp can produce only a limited amount of photosynthetic photon flux making them unsuitable for greenhouses where PPFD levels comparable to daylight are typically required
Solution Approach 1:
The invention merges the advantages of fluorescent lamps (low heat emission, close positioning capability) with the high output capability of multiple high-flux LED chips. By combining seven different LED chip types in an array, the system achieves both efficient heat management and high photosynthetic photon flux density output, exceeding the capabilities of individual fluorescent lamps while maintaining safe operating temperatures near plant canopies.
4Adaptability or versatility
If incandescent lamps are used to control flowering in plants, then flowering can be advanced or delayed, but the spectral power distribution is fixed and the form factor makes it difficult to control spatial intensity distributions
Solution Approach 1:
The invention applies local quality by using an array of LED chips with different spectral characteristics positioned at specific locations within the luminaire. This allows different spatial zones to emit different spectral compositions and intensities, enabling precise control over spatial intensity distribution while maintaining the ability to control flowering through appropriate spectral selection. Each LED channel can be independently controlled to create localized lighting conditions.
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
This system provides improved control over the spectral distribution of light, enhancing plant growth and health by maximizing the excitation of plant photopigments, reducing heat-related issues, and allowing for flexible LED arrangement, thus overcoming the limitations of prior art luminaires.
Implementation Method 1
one or more optical components mounted on a substrate and each optically coupled to at least one optical fiber that delivers laser radiation to the optical component
Implementation Method 2
a linear or elliptical holographic diffuser located to diffuse light emanating from said optical components
Implementation Method 3
one or more laser light sources optically coupled to said optical fibers, wherein said laser light sources generate optical radiation with one or more monochromatic wavelengths
Data Source
AI summary
Laser light is coupled to optical fibers arranged in a sheet, which may be in the form of netting, mesh or fabric. Scattering centers or bends in the optical fibers allow the coupled light to escape from the sides of the fibers. Depending on the selection of wavelengths for the lasers, the resulting luminous sheet may be used for illumination of crops grown in vertical farms. The laser wavelengths excite plant photopigments for predetermined physiological responses, and the light source intensities may be temporally modulated to maximize photosynthesis and control photomorphogenesis responses. Each laser may be independently controlled, and at least one laser may emit ultraviolet-C radiation. The luminous sheet may be used for purification of air flowing through an air duct.