| faithlu |
2007-03-15 12:58 |
華中理工大學(xué)碩士研究生論文（LED的封裝）
摘 要 ^T079=$5
隨著發(fā)光材料的開(kāi)發(fā)和半導(dǎo)體制作工藝的改進(jìn)，白光LED的發(fā)展迅速，它已經(jīng)趨向取代傳統(tǒng)的照明，白光LED的光效已經(jīng)由以前的20lm/w上升到了45lm/w。由于白光LED具有的長(zhǎng)壽命、無(wú)污染、低功耗的特性，未來(lái)LED還將逐步替代熒光燈、白熾燈成為下一代綠色照明光源。 f
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本文首先簡(jiǎn)單介紹LED的概念、特點(diǎn)、分類(lèi)以及現(xiàn)階段全球和國(guó)內(nèi)LED技術(shù)研究的進(jìn)展，提出了現(xiàn)階段白光LED存在的問(wèn)題。 xJhU<q~?
接著根據(jù)白光LED所存在的問(wèn)題，對(duì)白光LED的封裝工藝和原材料的選擇搭配進(jìn)行改進(jìn)，在本文中白光LED有兩種封裝方式，一種是支架式封裝形式，一種是大功率LED的封裝形式。整個(gè)封裝設(shè)計(jì)過(guò)程從以下幾個(gè)方面進(jìn)行的： t;O1IMF
(1)熒光粉涂抹的方式。熒光粉的涂抹方式對(duì)白光LED的發(fā)光分布與色溫的均勻度影響很大，熒光粉厚度較厚的位置黃光產(chǎn)生較多，色溫會(huì)較低，因此在芯片上形成的涂抹層必須是均勻。 iRw&49
(2)散熱的研究。由于結(jié)溫的上升會(huì)使發(fā)光復(fù)合的幾率下降，發(fā)光二極管的亮度就會(huì)下降，壽命和輸出光通也會(huì)隨著溫度的升高而下降，如果PN結(jié)產(chǎn)生的熱量能盡快的散發(fā)出去，不僅提高產(chǎn)品的發(fā)光效率，同時(shí)也提高了產(chǎn)品的可靠性和壽命。 I1=(. *B}
(3)封裝原材料的選擇。外封裝材料的選擇是建立在散熱的基礎(chǔ)上的，因此芯片、基板、支架、散熱器和填充材料必須是低熱阻，高導(dǎo)熱率的材質(zhì)。 ;YH[G;aJ
最后是對(duì)封裝好的兩種白光LED的特性參數(shù)進(jìn)行了測(cè)試和分析，并且通過(guò)改變封裝條件進(jìn)一步探討和分析了兩種封裝方式。 aC^$*qN-)
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關(guān)鍵詞：固體照明 白光半導(dǎo)體發(fā)光二極管 封裝工藝 熒光粉 散熱 U A-7nb
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Abstract $8 =@R'
With the development of material and the innovation of semiconductor manufacture technology, the efficiency of White LED is increasing from 20 to 45 lumens/watt, and has already begun to exceed that of incandescent lamps. Their life characteristics are important factors. When LEDs replace filter white light sources or colored neon lamps in signage, decorative and signaling applications, they will often be viable and efficient alternative. So LEDs will take a new era in “green lighting”. \N6\v5vh
First, The thesis introduces the concept and characteristics of LED and the development of LED technology research in the world and in china. p3]Q^KFS
Secondly, It states the package process of White LED in detail and discusses the following aspects: sYn[uPefj
One aspect is the coating method of phosphor, which influences the LED’s color temperature and range of available color properties, so，phosphor coating in manufacturing process must be uniform in thickness. pJ^ N A2
Another aspect is the heat dissipated. In general, the cooler the environment, the higher an LED’s light output will be. Higher temperatures generally reduce light output. and LED’s life. If the heat within the junction is dissipated by convection and conduction, their useful life and the efficiency of LED would be increase. 0A[e
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