Pulsed Blue Light Plant Cultivation Method
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Solution Overview
Problem
Existing plant cultivation methods using alternate high-intensity red and blue LED light irradiation lead to physiological disorders, increased running costs, and worker psychological stress, while also causing plants to wither after harvest.
Innovation Solution
A plant cultivation method involving alternating periods of carbon dioxide absorption and emission, with a dark period and a bright period of blue light irradiation at intensities below the light compensation point, using blue pulsed light with a photosynthetic photon flux density between 0.001 and 4.0 μmol·m−2·s−1, and a duty ratio of 20% or less, to enhance photosynthesis efficiency and reduce stress on plants and workers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-intensity red LED light and blue LED light are applied alternately to accelerate plant growth, then the growth speed of plants is improved, but physiological disorders occur in leaves and plants are prone to wither after harvest
Solution Approach 1:
The patent applies periodic pulsed light irradiation instead of continuous high-intensity light. The light source emits light in short pulses (e.g., 10 μs to 10 ms duration) with dark intervals between pulses, creating a periodic action pattern. This periodic illumination maintains plant growth acceleration while preventing physiological disorders and leaf withering that occur with continuous high-intensity light exposure.
Solution Approach 2:
The patent changes the temporal parameters of light irradiation from continuous to pulsed mode, and adjusts the intensity parameters to be lower than light compensation point during dark periods. By modifying the duty cycle (ratio of light-on time to total cycle time) and pulse duration, the system achieves both rapid growth and plant health maintenance, resolving the contradiction between productivity and reliability.
2Productivity
If high-intensity red LED light and blue LED light are applied alternately to accelerate plant growth, then the growth speed of plants is improved, but the running cost is increased
Solution Approach 1:
By using pulsed light irradiation with dark intervals instead of continuous illumination, the system reduces total energy consumption while maintaining growth acceleration effects. The periodic on-off pattern allows plants to utilize light energy more efficiently during pulse periods and recover during dark periods, achieving the same or better growth results with lower running costs.
Solution Approach 2:
The patent applies light irradiation partially (only during specific pulse periods) rather than continuously, using just enough light exposure to trigger the desired growth response. This partial action approach avoids excessive energy consumption while still achieving effective plant growth acceleration, resolving the contradiction between productivity and energy cost.
3Productivity
If high-intensity red LED light and blue LED light are applied alternately to accelerate plant growth, then the growth speed of plants is improved, but the psychological load on workers is increased
Solution Approach 1:
The pulsed light system creates periodic illumination patterns with dark intervals, which reduces the overall light intensity exposure in the cultivation environment. This periodic action diminishes the harshness of continuous high-intensity light, thereby reducing psychological stress and discomfort for workers who spend time in these environments while maintaining plant growth acceleration.
4Productivity
If blue light is applied at low intensity below light compensation point during dark period to accelerate growth, then the growth of plants is improved, but the light intensity must be precisely controlled
Solution Approach 1:
The patent transforms the control approach by changing from maintaining a precise continuous intensity level to controlling pulsed parameters (duration, frequency, duty cycle). This parameter transformation makes the system more manageable because pulse timing and duration can be controlled with standard electronic timing circuits, avoiding the need for complex continuous intensity regulation while still achieving the desired growth effect.
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 method accelerates plant growth, reduces the risk of physiological disorders, lowers running costs, and minimizes worker stress, while maintaining a night environment for plants, thereby promoting healthy growth and increased yields.
Implementation Method 1
a bright period in which blue light whose wavelength is 400 nm or greater and 500 nm or shorter is applied... an amount of carbon dioxide absorbed by photosynthesis is larger than an amount of carbon dioxide emitted by respiration
Data Source
AI summary
A plant cultivation method includes providing a growth period and a rest period alternately. In the rest period, a dark period and a bright period is alternately provided. In the dark period, an intensity of light applied to a cultivation target plant is lower than a light intensity at a light compensation point. In the bright period, blue light whose wavelength is 400 nm to 500 nm is applied at an intensity that is lower than the light intensity at the light compensation point. A one-cycle time T of repetition of the dark period and the bright period is 2 μs to 500 μs. A duty ratio ΔT/T of a bright period time ΔT to the one-cycle time T is 20% or smaller. The blue light has a photosynthetic photon flux density of 0.001 μmol·m−2·s−1 to 4.0 μmol·m−2·s−1.