共查询到18条相似文献,搜索用时 93 毫秒
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使用发射波长为395~400 nm的近紫外LED芯片来激发发射峰值波长分别在615,505和445 nm的红绿蓝三基色荧光粉,建立三基色荧光粉混光理论模型,制作不同色温下高显色指数白光发光二极管,研究其光电特性。实验结果表明,采用近紫外激发的三基色白光器件色温为3 000~9 000 K范围内,其显色指数均能保持在80~90之间;当色温大于5 000 K时,显色指数可以达到85;测试结果与理论计算吻合良好。最后,实验证明加入TiO2粉末可消除白光LED中残余近紫外线,三基色荧光粉白光LED色度参数受工作电流变化的影响较小。 相似文献
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利用黄色、红色和黄绿色3种荧光粉混合的方法制备了一系列大功率平面发光LED光源,深入研究了黄色、红色和黄绿色3种荧光粉分别对大功率白光LED光源的发光效率、显色指数以及色温的影响规律。研究结果表明,随着黄色荧光粉含量的增加,其发光效率明显提高,最高可达140 lm/W,而显色指数和色温略有下降。随着红色荧光粉含量的增加,其显色指数明显提高,最高可达85,而发光效率和色温明显降低。随着黄绿色荧光粉含量的增加,其发光效率、显色指数以及色温均不同程度地略有下降,但是其对大功率白光LED的色容差起到很好的调节作用。 相似文献
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荧光粉的吸收散射特性、粒径分布及荧光粉涂层的形状对白光LED色温角空间分布具有直接影响。通过Mie散射理论对不同形状的荧光粉涂层进行了光学计算仿真,研究了荧光粉涂层形状对白光LED空间色温分布的影响规律,以及不同形状的荧光粉涂层效率,并从中找出色温均匀性最佳的荧光粉涂层形状。根据仿真结果,采用具有精确控制喷胶量和喷涂位置功能的高速喷胶技术对1mm2大功率芯片的荧光粉涂层的涂敷工艺进行实验制作,控制器件的平均色温在5 000K,获得荧光粉涂层形状对白光LED色温角空间分布影响的测量结果与计算仿真结果相吻合。通过该方法制作的荧光粉涂层使白光LED的最小色温差异达到537K,远优于目前一般采用的荧光粉涂敷技术。 相似文献
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光转换白光LEDs的研究 总被引:7,自引:3,他引:4
采用固相法制备YAG:Ce、Gd光转换荧光粉,测量其激发光谱和荧光光谱,发现激发光谱存在2条激发带,其中428—501nm的激发带与GaN LEDs的发射光谱匹配,荧光光谱呈黄色宽带。将荧光粉与GaN管芯用环氧树脂封装在一起,制成白光LEDs,其CIE色度坐标为(0.27,0.33),显色指数为78.2,发光强度8cd,流明转换效率为6.37,优于市场同类产品。 相似文献
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YU Xin-mei RAO Hai-bo HU Yue LI Jun-fei HOU Bin 《半导体光子学与技术》2007,13(2):97-103
As the blue and yellow lights are complementary colors, a blue InGaN LED chip is coated hy a yellow phosphor film to generate white light based on luminescence conversion mechanism. The emitted light of a blue LED is used as the primary source for exciting fluorescent material such as cerium doped yttrium aluminum garnet with the formula Y3Al2O12 : Ce^3+ (in short: YAG : Ce^3+ ). The matching of the spectrum of the blue LED chips and the YAG : Ce^3+ yellow phosphor is studied to improve the conversion efficiency. The packaging methods and manufacturing processes for high power single chip-white LEDs are introduced. The uniformity of the output white light is investigated. Based on the characteristics of the high power white LEDs, some approaches and processes are suggested to improve the light uniformity when they are fabricated. The effectiveness of those approaches on the improvement of LEDs is discussed in detail and some interesting conclusions are also presented. 相似文献
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We packaged a series of high power white LEDs by covering the blue LED chips with yellow phosphor, red phosphor and the two phosphors mixed by appropriate mass ratio, respectively, and discussed the excitation and emission spectrum of yellow phosphor and red phosphor and the characteristics of the LEDs. We found that the luminous efficacy of the white LEDs covered with the two phosphors mixed by appropriate mass ratio was lower than that of the white LEDs covered with yellow phosphor, but the color rendering index was improved observably. 相似文献
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We packaged a series of high power white LEDs by covering the blue LED chips with yellow phosphor, red phosphor and the two phosphors mixed by appropriate mass ratio,respectively,and discussed the excitation and emission spectrum of yellow phosphor and red phosphor and the characteristics of the LEDs.We found that the luminous efficacy of the white LEDs covered with the two phosphors mixed by appropriate mass ratio was lower than that of the white LEDs covered with yellow phosphor,but the color rendering index was improved observably. 相似文献
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荧光粉浓度和电流强度对白光LED特性的影响 总被引:4,自引:0,他引:4
讨论了荧光粉浓度及驱动电流强度对白光LED特性的影响。采用软件模拟实验和实际封装测试相结合的研究方法进行分析研究。对荧光粉浓度变化对白光LED光通量和相关色温(CCT)的影响进行了三维光线追迹模拟,并且进行了实际的封装验证。另外对白光LED的节温和显色性也做了深入细致的研究。研究结果表明:CCT随着荧光粉浓度的增大而减小,光通量则先上升后下降。同时由荧光粉浓度和驱动电流强度变化所引起的节温升高会降低荧光粉的转换效率。对显色性而言,采用高浓度荧光粉封装的白光LED有相对低的显色指数;并且显色指数随着驱动电流强度的增加而升高,最终趋于稳定。 相似文献
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根据色度学基本原理,对荧光粉转换白光发光二极管(LED)和两基色、三基色白光LED进行了配色计算,得到了距离理想白光点色度坐标(1/3,1/3)小于0.5%范围内的众多基色组合,同时对光视效能、显色指数和荧光粉转换效率等参数进行了分析,提出了荧光粉转换白光LED和两基色、三基色白光LED的最佳基色组合,并在实验上对荧光粉转换白光LED进行了验证。 相似文献