All visible light sources have an important parameter called luminous flux, and grow lights are no exception.The luminous flux is of great significance to human visual perception. On the one hand, according to the different luminous flux, the light response felt by the naked eye is also different; On the other hand, according to the difference of human vision, the visual perception of the naked eye to the same luminous flux in the same wavelength band is also different.
Understanding the relationship between the naked eye and luminous flux, what is the relationship between LED plant growth light flux and plants? Let’s first look at the concept of luminous flux.
Luminous Flux Concept
Luminous flux refers to the radiant power that the human eye can perceive, which is the product of the radiant energy of a certain band per unit time and the relative visibility rate of the band, and the unit is lumens (lm). Because the relative visibility of the human eye to different wavelengths is different, even if the radiation power of different wavelengths is the same, the luminous flux is not equal. Conversely, even if the luminous flux is the same, if it is light of different wavelengths, its radiation power is not the same.
Luminous flux calculation method
Luminous flux refers to the derived amount of radiant flux evaluated according to the international standard human visual characteristics, the representative symbol is Φ, and its calculation formula is:
Among them, Km is the maximum value of spectral luminous efficacy 683lm/W, V(λ) is the standard standard spectral luminous efficiency function, Φeλ is the spectral density, and λ is the spectral luminous efficiency. 1lm is equal to the luminous flux emitted by a point light source with a uniform luminous intensity of 1 candela (1cd) within a unit solid angle of 1 steradian (sr), that is, 1lm=1 cd·sr.
The relationship between LED plant light flux and plant growth
Luminous flux can be simply understood as the amount of light passing through a unit of time and a unit area, just like water flow, it flows out, flows or flows into less water in one second, and the luminous flux flows out, flows or flows into less light in seconds. That is to say, the red light with a wavelength of 680 can reach 1000 (lm) under certain conditions, and the green light with a wavelength of 520 can also reach 1000 (lm) under another condition.
For plants, the most important thing is to emit the red and blue light that the plants need, or to simulate the full spectrum of sunlight to help grow high-quality and high-quality plants,the most important factors affecting the lighting effect of LED plant lights include light quality, light intensity, and lighting time. So the same red light and green light with a luminous flux of 1000 (lm), one plant absorbs a lot, and the other plant absorbs almost no, therefore, the luminous flux cannot be fully used as a factor that an LED plant growth light may have an impact on the lighting effect of plants.
However, if it is the same wavelength of red light that plants need, the greater the luminous flux, the indirect indication that the red lamp beads of the LED plant light emit a large amount of light, the plants can get more sufficient light, and the growth effect will be better.
To sum up, for the field of using LED grow lights to grow plants, the luminous flux is not the main parameter to measure the value of LED grow lights for the time being. However, it can be used as a reference. If the wavelength is determined, the light source with the larger luminous flux can provide stronger illumination.
