Optimization Of LED Combined Light Source And Its Application In Cultivation Of Fagopyrum

Light emitting diode(LED) is a kind of semiconductor light source,which has the advantages of high luminous efficiency,low energy consumption,long service life,full color and environmental protection.LED is a kind of cold light source,which mainly exists in the form of monochromatic light and the spectrum is mainly distributed in the visible light area,which has a high degree of agreement with the plant photosynthesis absorption spectrum.Proper selection of LED type and combination design can obviously improve the supplementary lighting of plants,which overcomes the shortage of traditional artificial light source in greenhouse.In this paper,LED is used as Lambert light source.According to the sparrow rule,the physical and the mathematical models of LED combined array light source are proposed.Two evaluation indexes of uniform light intensity and uniform R/B or R/FR ratio distribution are established.The first index namely the uniformity of the light intensity for LED surface light source in the lighting area of the observation plane shall not be less than 0.81.When there are many kinds of LEDs,the uniformity of R/B or R/FR ratio distribution is the second index of design,and the treatment method is also applicable to the same type of light intensity and R/B or R FR distribution.The software of MATLAB2013 a and Originpro 2016 are used for calculation,design,optimization and simulation.Two software are developed to calculate the optimal LED center distance and the LED light intensity distribution in the simulated observation surface.Based on the modular design concept,the LED combined array light source with the optimal design scheme is also developed.Red,blue,and white LEDs are used to cultivate Fagopyrum seedlings,respectively.Through the measurement of four indexes of photosynthesis of buckwheat cultivated for 23 days and the determination of its component content after harvest,it is found that LED array light source has regular regulation effect on appearance,shape,light cooperation index,and component content of Fagopyrum.