With the development of urbanization, the area of cultivated land is becoming scarce, and the environment is becoming worse and worse because of the long-term economic pattern. Food safety is becoming increasingly prominent. With the "Twelfth Five-Year Plan for the Development of Agricultural Science and Technology (2011-2015)" pointing out that "it is a key period for building a well-off society in an all-round way, and it is also a crucial stage for promoting agricultural modernization in the further development of industrialization and urbanization. The task of ensuring national food security, increasing farmers'income and sustainable agricultural development is even more arduous. We must speed up the innovation of agricultural science and technology and enhance the support ability of agricultural science and technology. " The idea of plant factory also flourished in the new policy and entered the stage of substantive application.

CSA Research pointed out that in 2016, China's application of beyond lighting technology has made some progress. The Shenzhou 11 manned spacecraft carried out scientific experiments on lettuce cultivation in space, and LED plant illumination became a bright spot in Shenzhou's flying sky. In 2016, semiconductor lighting applications market demand can be described as the East sunrise west rain, LED lighting and other traditional alternative markets are accelerating penetration, plant lighting and other emerging market segments become a hot spot. At the same time, the 13th Five-Year Plan of semiconductor lighting industry will be released in early 2017. The promulgation of the Plan will give a clear direction to the next development focus and development mode of the industry.

With the advent of the 13th Five-Year Plan, seven key areas of development will be put forward, namely, LED energy-saving light source, three-dimensional soilless cultivation, light-temperature coupling energy-saving environmental control, nutrient solution control, network-based intelligent management, artificial light plant factory, natural light plant factory integrated demonstration and so on, in order to alleviate the increasingly prominent food crisis. It has promoted the related disciplines research. As the "LED energy-saving light source" in the seven key areas of development, our UVLED in the field of plant factories can be said to be pivotal, broad prospects.

The productivity of open-field agriculture is directly related to the quality of illumination, so the saturation of light depends on the severity of weather effects. Similarly, the speed of plant growth is directly related to the weather-affected illumination. The plant factory concept has many advantages: high production efficiency, good controllability and wide application prospects. It is undoubtedly a high-efficient, harmless and high-tech agricultural mode that plants in plant factories use electric light sources to lengthen and replenish the deficiency of sunlight and provide the needed light.

The contribution of different spectra of sunlight to plant photosynthesis is different, only 400-700 nm range of light for plant photosynthesis for effective radiation, and plant carbohydrate synthesis photoreaction process. According to the distinction between visible light and invisible light, the invisible light contains a wavelength less than 380 nm, which is called "ultraviolet light" (UV), for effective radiation of plants, UV and far-infrared light on plant growth and development has regulatory function, has important application value for agricultural production.

The indoor UV radiation distribution is closely related to the transparency of glass, shading net and greenhouse film materials. The above materials affect the absorption, filtering, shading and aging of natural light, and ultraviolet light (UV) affects the coverage. The transmittance of the material is only 15.9-21.1%, which greatly reduces the utilization quality of sunlight and greatly damages the UV radiation. The UV radiation of plants in traditional agricultural factories is also caused by the extremely uneven distribution of UV radiation components and illumination in traditional supplementary lamps and lanterns.

At present, fluorescent lamp, mercury lamp and high pressure sodium lamp are the main spectra of traditional agricultural planting or artificial cultivation. They are only the combination of red and blue light emitted by LED, and obviously lack the components of ultraviolet spectrum. Due to the lack of ultraviolet light in the facility, serious growth and quality problems of plants have been caused. Optimizing the composition of high-efficiency spectroscopy for supplementary light is urgently needed. As a new type of energy-saving, controllable, adjustable and efficient application light source, LED has made breakthroughs in the core technology and applied technology has been continuously extended. Utilization and regulation of ultraviolet light in plant factories is very important to ensure high quality and high yield. The application of artificial controlled ultraviolet (UV) light source to supplement UV radiation technology can reduce chemical methods leading to plant growth and improve plant quality, which is an important guarantee for the production of green organic food. However, up to now, there is little research on the regulation mechanism of medium and long wave ultraviolet light supplementation on vegetable nutritional quality, especially antioxidants. Lack of effective technology and equipment for ultraviolet light management.

UV artificial light regulation has a very good application value in realizing high quality and high yield of facility horticulture, but it can be applied to the variety of crops, the application target as the choice of application dose and the opportunity of irradiation to ensure the application safety. Vegetables, medicinal plants, flowers and fruit trees can be used in the selection of crop species. The main application objectives are to control plant growth and improve crop quality, such as increasing the content of antioxidants in vegetables, increasing the accumulation of secondary metabolites in medicinal plants, and accelerating the synthesis and accumulation of chromogenic substances in flower leaves and petals. In order to control the ultraviolet (UV) effect, the UV radiation must be well controlled, such as short-term small dose, intermittent repeated irradiation, pre-harvest short-term irradiation and other reasonable dosage.

Therefore, the emergence of UVLED and its large-scale application in the field of agricultural lighting artificial light of various plants, its energy-saving environmental protection, cold light source, long service life, small size, light quality pure, high light efficiency, rich wavelength types, spectral energy easy to composite, convenient modulation and other outstanding advantages, will help a new round of plant factory model. In this way, the light source and wavelength band can be used more reasonably to meet the different needs of different plants for light, and to achieve the purpose of increasing production, environmental protection and pollution-free.