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功率型白光LED封装设计的研究进展 总被引:2,自引:0,他引:2
综述了功率型白光LED封装的研究现状和存在的问题,着重从LED封装结构和封装材料两个方面进行了详细的评述,在现有蓝光芯片激发钇铝石榴石(YAG)荧光粉来实现节能、高效的白光LED照明的基础上,介绍了可以提高功率型白光LED的取光效率和空间色度的均匀性的各种封装结构和材料.指出新的封装结构、封装材料和封装工艺的有机结合以获得高取光效率,延长功率型白光LED的使用寿命,节约整体封装结构的成本,从而推进LED同体光源的应用是今后功率型白光LED研究的重点. 相似文献
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荧光粉发光LED作为白光光源在照明领域有着广泛的应用。长时间工作,荧光粉发光LED将出现色温偏移现象。荧光粉发光LED的色温偏移与芯片衰减和荧光粉衰减有关。提出了一种能同时考虑芯片衰减和荧光粉衰减的数学模型。从理论上分析了芯片衰减和荧光粉衰减对荧光粉发光LED的色坐标及色温变化的影响。提出了一种利用蓝光LED与荧光粉发光LED混合,通过对蓝光LED进行负反馈控制,保证蓝光辐射在全白光中的辐射功率比值恒定,从而实现色温稳定的白光LED照明系统。 相似文献
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荧光粉转换白光LED具有高能效、低成本、长寿命等优势,广泛应用于照明领域,提高荧光粉转换白光LED的光效一直是该领域的研究热点。为了对白光LED的高性能封装进行设计优化和制备,采用模拟仿真以及实验测试相结合的方式,对LED芯片封装进行研究分析,采用了特制支架和双芯片封装,提高灯珠光效,在此基础上,改进了荧光粉涂覆工艺,提高了荧光粉激发效率,整体提高LED光效约6%,且研究了远程荧光粉与芯片的距离变化时LED的光效变化。 相似文献
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荧光粉受激发产生的白光LED照明光源存在显色指数较低的问题.对此提出一种利用光谱拟合反演高显指目标光谱的方法,针对已知白光LED计算提高该光源所需补充的单色光LED种类及光谱系数.利用光谱拟合方法分析添加不同波段的光谱对白光LED显指和色温的影响.并通过拟合反演的方法进行补光设计,使用一到两种单色光LED,将冷白光源和中性白光源的显指分别提高至92.3和96.8.实验结果表明,使用红光与蓝绿光、低波长绿光LED补光后,大幅度提高了荧光粉受激发产生的白光LED光源的显色性. 相似文献
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Phosphor-Concentration-Dependent Characteristics of White LEDs in Different Current Regulation Modes
Jiun Pyng You Nguyen T. Tran Yuan-Chang Lin Yongzhi He Frank G. Shi 《Journal of Electronic Materials》2009,38(6):761-766
Phosphor-concentration-dependent characteristics of white light-emitting diodes (LEDs) under different current regulation
conditions were investigated. It is found that the phosphor conversion efficiency of white LEDs driven under constant current
is lower than that under pulse current. In addition, white LEDs driven under constant current exhibit higher junction temperature
than under pulse current, and the difference is phosphor concentration dependent. For both pulse and constant current modes,
white LEDs show relatively stable optical characteristics at relatively higher drive currents, when relatively higher phosphor
concentrations are used. At relatively higher phosphor concentrations, the correlated color temperature and the chromaticity
coordinates have also been observed to be relatively stable for white LEDs in both constant and pulse current modes. 相似文献
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As well known, the light emission characteristics of the high power light-emitting diodes (LEDs) are very sensitive to the various driving conditions, especially the injected electric current and the junction temperature in operation. In this work, the dependency of the emission light from high power LEDs upon the driving electric current and the junction temperature will be explored in details. One integrated measurement system is proposed for the study in simultaneously obtaining all the thermal–optic–electric characteristics of LEDs throughout the measuring. Based on the basic feedback control methodology, one simple maintaining procedure is applied for the stable light emission in high power LEDs. It shows the robustness of the maintaining procedure from the environment change with the least heat dissipation in the operation of the high power LEDs. The results imply that all the thermal, the optic, and the electric properties of the high power LEDs should be taken into consideration in the same time rather than separately when maintaining their operation. 相似文献
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To improve the heat dissipation of high-power light-emitting diodes (LEDs), a cooling system with thermoelectric cooler (TEC) is investigated. In the experiment, the 6 × 3 W LEDs in two rows are used to compose the light source module and the environment temperature is 17 °C. The temperatures of heat dissipation substrate of LEDs and cooling fins of a radiator are measured by K type thermocouples to evaluate the cooling performance. Results show that the temperature of the substrate of LEDs reaches 26 °C without TEC. However, it is only 9 °C when the best refrigeration condition appears. The temperature of the substrate of LEDs decreases by 17 °C since the heat produced by LEDs is absorbed rapidly by TEC and dissipated through the radiator, and the junction temperature of LEDs reaches only 45 °C which is much lower than the absolute maximum temperature of LEDs (120 °C). The experiment demonstrates that the cooling system with TEC has good performance. 相似文献
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One of the methods to derive white light from light emitting diodes(LEDs) is the multi-chip white LED technology, which mixes the light from red, green and blue LEDs. Introduced is an optimal algorithm for the spectrum design of the multi-chip white LEDs in this paper. It optimizes the selection of single color LEDs and drive current controlling, so that the multi-chip white LED achieves the target correlated color temperature (CCT), as well as high luminous efficacy and good color rendering. A CCT tunable LED light source with four high-power LEDs is realized based on the above optimal design. Test results show that it maintains satisfactory color rendering and stable luminous efficacy across the whole CCT tuning range. Finally, discussed are the design improvement and the prospect of the future applications of the CCT tunable LED light source. 相似文献
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倒装大功率白光LED热场分析与测试 总被引:20,自引:7,他引:13
散热是影响大功率LED正常工作及器件寿命的关键因素,本文利用有限元法(FEM)对W级倒装大功率白光LED的空间温度场分布进行了模拟计算,结果与用自制的测试装置测量的温度分布相吻合。在此基础上,保持电流密度不变,研究芯片尽寸与结区温度的关系,计算出在当前的发光效率和封装结构条件下,由于散热条件的限制,芯片能承受的最大功率和能达到的最大尺寸。 相似文献
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开发了一种应用于大功率LED散热的排式热管散热器。在大空间自然对流冷却环境中,分别在0°、30°、60°、90°放置条件下对其启动性能、均温特性、散热性能进行了试验研究。试验结果表明:散热器启动性能良好,启动时间约为67min;在输入功率为30~70W的范围内,热源表面中心点温度不超过75℃;各倾角下散热器均具有较低的总热阻及扩散热阻,0°放置时总热阻最小。基于试验所得结果,通过计算LED结温论证了排式热管散热器在各倾角条件下均可满足热输出70W以下大功率LED散热的需求。 相似文献