植物照明用荧光粉转换白光二极管的研究

L ED具有效率高、体积小、功耗低、寿命长等优点,并且因其具有可轻易实现宽幅光谱调控的特性,在植物照明领域崭露头角.植物照明用L ED分为两大类,一类是单色光L ED,另一类是白光L ED,其中植物照明用白光L ED可与单色L ED混合或者单独使用从而实现植物补光照明.植物封装用白光L ED大部分采用蓝光L ED芯片或...

Phosphor-Converted White Light-Emitting Diodes for Plant Lighting

LED has the advantages of high efficiency,small size,low power consumption,long life and son on,and it can easily achieve wide spectral regulation,which makes it stand out in the field of agriculture.Plant-growth light-emitting diodes(LEDs)can be divided into two categories,one is monochromatic LED,and the other is a White light-emitting diode(WLED),WLEDs used for plant growth are either mixed with monochromatic LED or used alone to realize plant supplementary lighting.Most of the WLEDs on plant growth is composed of a blue LED chip or a UV LED chip packed with phosphors,that is,phosphor-converted WLEDs,however,the obtained spectra are concentrated in the bluish visible light,and the efficiency of photosynthesis to plants is relatively poor.The absorption spectra of the plant are not full-band but selective,based on the particularity of the absorption spectra of plant,the color rendering performance of the spectra of WLEDs is regarded as the standard to judge whether the spectra are suitable for plant growth,the average color rendering index Ra,special color rendering index R9(saturated red light)and R12(saturated blue light)were considered as the main performance evaluation parameters of WLEDs on plant growth.In order to design WLEDs with good performance and can be used in the field of agriculture,common commercial YAGG was selected as green color conversion material and(Sr,Ca)AlSiN 3 was selected as red color conversion material.(Sr,Ca)AlSiN 3 red phosphors were prepared by traditional high temperature solid state method and the spectral performance was analyzed.By importing the built LED structure models into the simulation software LightTools and introducing the characteristic parameters of green phosphor particles,red phosphor particles and blue chip respectively,the simulation models of WLED were built based on a single blue LED chip(450 nm)and two blue LED chips(450+470 nm)separately,the color rendering performance of the spectral power distribution of WLEDs under different correlated color temperature was studied under the two excitation modes.In order to verify the difference of the color rendering index of the spectra obtained by the two excitation modes,WLEDs were prepared by combining(Sr,Ca)AlSiN 3 and YAGG phosphors.Eventually,a real WLED was encapsulated by coating the combination of Sr_0.8Ca_0.12AlSiN₃∶0.08Eu²⁺and YAGG phosphors on two blue chips and led to an optimal spectrum of Ra=91.2,R9=96.1,R12=78.9,LER=126 lm·W^(-1 )which contains the blue and red light needed for plant growth.