【摘要】：為了解決未來人口的糧食問題,植物工廠應(yīng)運(yùn)而生。而光照作為植物生長(zhǎng)發(fā)育的重要因素,開發(fā)高效、無污染并且適宜植物生長(zhǎng)的光源則成為重中之重。隨著發(fā)光二極管(Light Emitting Diode,LED)的迅速發(fā)展,LED以其節(jié)能、環(huán)保、冷光源并且光譜可調(diào)逐漸成為植物工廠的主流光源。由于近些年紅色熒光粉種類增多和穩(wěn)定性不斷提高,不同于傳統(tǒng)將紅藍(lán)光LED芯片組合實(shí)現(xiàn)紅藍(lán)光的方式,本文提出一種新型紅藍(lán)光的實(shí)現(xiàn)方式:將紅色熒光粉混合硅膠涂覆在藍(lán)光LED芯片上,即熒光粉轉(zhuǎn)化LED(phosphor converted LED,pc-LEDs),即可在單顆芯片實(shí)現(xiàn)植物所需紅藍(lán)光。(一)為了得到理想的植物照明效果pc-LEDs器件,本文分別采用傳統(tǒng)熒光粉點(diǎn)膠技術(shù)、自適應(yīng)涂層技術(shù)實(shí)現(xiàn)紅藍(lán)光,并對(duì)器件進(jìn)行結(jié)溫測(cè)試、脈沖寬度調(diào)制(Pulse-Width Modulation,PWM)調(diào)光測(cè)試、以及老化性能測(cè)試,結(jié)果顯示:傳統(tǒng)球形涂層結(jié)溫為90℃,而自適應(yīng)涂層結(jié)構(gòu)結(jié)溫在80℃左右;PWM調(diào)光下器件紅藍(lán)光量子數(shù)比基本不變;而隨著時(shí)間的推移,紅藍(lán)光量子比從5.3衰減,在2000h后穩(wěn)定于5.0。當(dāng)粉膠比大于1:13時(shí),傳統(tǒng)球形熒光粉結(jié)構(gòu)在空間紅藍(lán)光子比分布上呈現(xiàn)不均勻性,中心紅藍(lán)光子比偏小,邊緣偏大;自適應(yīng)涂層結(jié)構(gòu)在-60~60°內(nèi)呈現(xiàn)出比較高的均勻性,但由于杯碗的反射作用以及杯碗粘附的熒光粉,邊緣區(qū)域呈現(xiàn)出不均勻性。為了改善傳統(tǒng)球形結(jié)構(gòu)的空間紅藍(lán)光子比分布均勻性,采用改進(jìn)的雙冠型熒光粉涂層技術(shù),在一定程度上提高了中心紅藍(lán)光子比,但效果不明顯,邊緣紅藍(lán)光子比依舊很高。(二)為了得到空間紅藍(lán)光子比分布均勻的熒光粉層結(jié)構(gòu),本文采用蒙特卡洛思想借助matlab模擬該LED的光子傳輸過程:包括LED發(fā)光模型、吸收和散射模型、隨機(jī)步長(zhǎng)和隨機(jī)波長(zhǎng)的獲得算法、熒光粉層離散化處理和出界判斷算法。通過仿真和實(shí)驗(yàn)對(duì)比確立仿真各項(xiàng)參數(shù),其中散射系數(shù)為2.0mm-1,吸收系數(shù)為1.0mm-1,并在仿真模型上驗(yàn)證了球形結(jié)構(gòu)的缺陷。本文提出一種類似正態(tài)分布的新型紅色熒光粉層結(jié)構(gòu),對(duì)于小角度前向散射機(jī)制的藍(lán)光光子進(jìn)行全反射和增加光程處理,對(duì)于邊緣區(qū)域光子進(jìn)行減少光程處理。將這種新型結(jié)構(gòu)同與傳統(tǒng)球形結(jié)構(gòu)置于紅藍(lán)光子比為6.0區(qū)間對(duì)比,通過模擬確定該結(jié)構(gòu)最大厚度為2.2mm以及該結(jié)構(gòu)σ2值為0.25。相比于傳統(tǒng)球形結(jié)構(gòu),該結(jié)構(gòu)下不同角度對(duì)應(yīng)紅藍(lán)光子比方差從0.445減少到0.0429,下降了90%。該結(jié)構(gòu)下空間紅藍(lán)光分布具有非常高的均勻性。(三)為了驗(yàn)證pc-LEDs用于植物照明的可行性,本文采用自制不同紅藍(lán)光子比的pc-LEDs燈具照射豌豆苗,各組光量子通量密度(Photosynthetic Photon Flux Density,PPFD)均為70μmol·m-2·s-1。收獲后,測(cè)量結(jié)果表明:當(dāng)紅藍(lán)光子比為9.3時(shí),豌豆苗的干重和莖長(zhǎng)都達(dá)到最大值;紅藍(lán)光子比為7.2時(shí),葉綠素的含量最高。
[Abstract]:In order to solve the food problem of future population, plant factory came into being. Light as an important factor in plant growth and development, the development of efficient, pollution-free and suitable for plant growth light source is the most important. With the rapid development of (Light Emitting diodes, LEDs have become the mainstream light source in plant factories because of their energy saving, environmental protection, cold light source and adjustable spectrum. Due to the increasing variety and stability of red phosphors in recent years, it is different from the traditional combination of red and blue LED chips to achieve red and blue light. In this paper, a new kind of red and blue light is proposed: the red phosphor mixed silica gel is coated on the blue LED chip, that is, the phosphor transforms the LED (phosphor converted LEDX pc-LEDs), which can realize the red and blue light needed by plant on a single chip. (1) in order to obtain the ideal plant lighting effect, the traditional phosphor dotting technique and the adaptive coating technology are used to realize the red and blue light, and the junction temperature and the Pulse-Width modulation dimming test are carried out. The results of aging test show that the junction temperature of conventional spherical coating is 90 鈩，

本文編號(hào)：2182662