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交流发光二极管热特性的模拟分析 总被引:2,自引:0,他引:2
由于交流发光二极管(AC-LED)在实际应用中无需交流/直流整流变压器,它的发展越来越被关注。随着器件功率的增大,芯片结温升高,对器件的光通量、光功率及寿命等产生负面影响,所以精确掌握AC-LED的温升规律就成为芯片设计的关键。运用FloEFD有限元软件进行模拟仿真1 W白光AC-LED分别在直流和交变功率驱动下的瞬态热特性,结果表明在加载交变信号情况下,器件结温会以直流信号的结温为中心周期振荡,振荡的频率与输入功率频率相同,但有明显的相位移动。同时,AC-LED在不同的输入功率和频率下的结温变化显示稳态时的平均结温和结温振荡幅度都随功率的增大而线性上升,但随着频率的增大而降低。 相似文献
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由于芯片之间存在的热耦合效应,多芯片LED器件内部存在复杂热学规律。本文通过多芯片LED热学模型描述多芯片LED器件系统内部热阻支路路径,进而通过有限体积数值计算多芯片LED器件结温。通过本文试验验证,单颗芯片、2颗芯片、3颗芯片以及4颗芯片在负载不同电功率(0.3~1.2 W)情况下,结温的测试值和计算值的最小误差值为0.8%,最大误差值为6.8%,平均误差值为3.4%,计算结果与测试结果基本保持一致,因此有利论证了多芯片LED热学模型可为评价多芯片LED器件热学性能提供重要的参考作用,有助于更全面分析多芯片LED热阻内部芯片之间的热耦合效应。该实验结果为准确预测多芯片LED器件内部结温提供了重要理论依据。 相似文献
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为了降低单管半导体激光器的结温、提高器件的散热效果,基于C-mount热沉的热特性分析提出了一种优化的台阶热沉结构,研究了单管激光器结温和腔面侧向温度分布曲线的影响。在热沉温度298 K和连续输出功率10 W的条件下,腔长为1.5 mm的典型C-mount封装结构激光器的结温为343.6 K,热阻为4.6 K/W。通过在典型C-mount热沉中引入台阶结构,使封装激光器的结温降低为333.8 K,热阻减小到3.5 K/W。计算表明,其输出功率可提高近20%。 相似文献
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《发光学报》2021,42(5)
有机发光二极管(OLED)器件性能的提高一直是有机电致发光领域备受关注的研究课题之一,通过优化OLED器件中的载流子平衡是提高OLED器件性能的一个非常重要的手段。但是,调控空穴传输层或电子传输层中的分子取向,从而优化器件中的载流子平衡未被关注。本文通过对空穴传输层进行不同温度的退火处理来改变空穴传输层中的分子取向,研究分子取向对其空穴迁移率和OLED器件性能的影响。研究发现,退火温度的升高使得空穴传输层中具有垂直取向的分子的比例增加,促进了空穴迁移率的提高。当把具有不同分子取向的空穴传输层应用于OLED器件时,可以清楚地观察到载流子平衡因子对器件性能的影响。 相似文献
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有机发光二极管(OLED)器件性能的提高一直是有机电致发光领域备受关注的研究课题之一,通过优化OLED器件中的载流子平衡是提高OLED器件性能的一个非常重要的手段。但是,调控空穴传输层或电子传输层中的分子取向,从而优化器件中的载流子平衡未被关注。本文通过对空穴传输层进行不同温度的退火处理来改变空穴传输层中的分子取向,研究分子取向对其空穴迁移率和OLED器件性能的影响。研究发现,退火温度的升高使得空穴传输层中具有垂直取向的分子的比例增加,促进了空穴迁移率的提高。当把具有不同分子取向的空穴传输层应用于OLED器件时,可以清楚地观察到载流子平衡因子对器件性能的影响。 相似文献
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In this paper, we describe an optimization process of thermal design for the light lamp which utilizes the Light Emitting Diode (LED) module as a lighting source. The thermal performance of the LED module was shown to significantly improve by the optimization process of cooling system attached with it. A wind circulating cooling system was designed for the LED arrays with the input power of 60?Watts and another heat pipe cooling system was designed for the input power of 144?Watts. The effects of design parameters such as air temperature and air velocity on the thermal performance of LED lamp were investigated. Thermal performance of the two cooling systems was compared for practical application. 相似文献
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Thermal and induced flow characteristics of radio frequency surface dielectric barrier discharge plasma actuation at atmospheric pressure 下载免费PDF全文
Thermal and induced flow velocity characteristics of radio frequency(RF) surface dielectric barrier discharge(SDBD)plasma actuation are experimentally investigated in this paper. The spatial and temporal distributions of the dielectric surface temperature are measured with the infrared thermography at atmospheric pressure. In the spanwise direction, the highest dielectric surface temperature is acquired at the center of the high voltage electrode, while it reduces gradually along the chordwise direction. The maximum temperature of the dielectric surface raises rapidly once discharge begins.After several seconds(typically 100 s), the temperature reaches equilibrium among the actuator's surface, plasma, and surrounding air. The maximum dielectric surface temperature is higher than that powered by an AC power supply in dozens of k Hz. Influences of the duty cycle and the input frequency on the thermal characteristics are analyzed. When the duty cycle increases, the maximum dielectric surface temperature increases linearly. However, the maximum dielectric surface temperature increases nonlinearly when the input frequency varies from 0.47 MHz to 1.61 MHz. The induced flow velocity of the RF SDBD actuator is 0.25 m/s. 相似文献
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有机发光二极管(OLED)具有功耗低、重量轻、色域宽、响应时间快及对比度高等优点,在全彩平板显示和固态照明等领域均显现出巨大的应用潜力,受到人们的广泛关注.然而,较低的光输出效率使得器件的外量子效率远低于内量子效率,这严重制约了OLED器件的发展和应用.因此如何提高OLED器件的光耦合输出效率已成为备受关注的研究课题.本文主要介绍了采用非周期微纳结构提高OLED器件光耦合输出效率的最新研究进展,对随机微纳透镜结构、光散射介质层、聚合物多孔散射薄膜、随机凹凸波纹结构及随机褶皱结构等多种对器件亮度分布和光谱稳定性无明显影响的光耦合输出技术进行了总结和讨论.最后,对提高OLED器件光耦合输出研究做了总结和展望. 相似文献
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Since microspeakers are widely used in mobile phones, high power is usually applied to obtain sufficient output sound pressure. However, the electric power is almost converted into heat, leading to the thermal problem in microspeakers. Compared with large loudspeaker, microspeakers are smaller and the under yoke is relatively closed, causing the heat transfer more complex. In this study, a three-stage nonlinear thermal model was proposed for analyzing the thermal behavior in microspeakers. The inside air is a buffer area between the voice coil and magnet, and modeled as a middle stage of the heat transfer. The forced convection is still significant in microspeakers while the eddy current can be ignored. In order to obtain the thermal parameters of the model, a corresponding parameter identification method was put forward. The basic linear parameters and forced convection parameters were all obtained by measuring and fitting the temperature curves of voice coil at different single tones. A series of experiments were conducted to verify the proposed model and parameter identification method, and the results showed good aggrement between the measured and predicted temperature curves for different input signals. The proposed model was valid and accurate, and may be helpful for the design and application of microspeakers. 相似文献
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有机电致发光器件的稳定性与其封装结构密切相关,封装技术的优劣直接影响有机电致发光二极管器件的寿命.本文采用热阻抗模型对三种常用有机电致发光二极管器件封装结构进行热阻抗分析,并利用ANSYS有限元分析软件的热分析模块对热特性进行研究,得出各种器件封装结构的温度场分布,根据温度场分布比较得出各种封装结构散热性能的差异.分析得出,传统后盖式封装结构与混合封装结构散热效果相差不大,Barix封装结构具有最好的散热性能.模拟仿真结果显示,当玻璃厚度从0.5 mm增加至0.9 mm时,传统封装结构的发光层温度升高了0.124℃,Barix封装结构的发光层温度升高了0.262℃,表明玻璃层厚度的增减对有机电致发光二极管器件的散热影响较小.改变器件表面空气流动速度,使对流系数从25W/(m2·K)变为85W/(m2·K)时,传统封装结构有机电致发光二极管发光层的温度由42.911℃递减到26.85℃,可见增大表面空气流动速度对降低有机电致发光二极管有源层的温度作用显著. 相似文献
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分析比较了在不同输入功率条件下1 W GaN基LED样品的热学特性,得出了有效热阻随加载功率的变化规律。基于瞬态热测试方法,讨论了结-环境热阻与输入功率之间的关系。加载电流为100~500 mA的区域随着电功率增加,有效热阻明显降低;当电流增至500 mA以上时,有效热阻减小幅度越来越小;而当加载电流为900~1 650 mA时,结-环境的热阻随着电功率的增加而缓慢升高。随着注入电功率的增加,在不同电流区域同一个样品的热阻变化趋势却是相反的,这个现象归因于串联电阻热耦合随输入功率的变化。该结果对分析功率型LED热特性具有一定参考价值。 相似文献
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Previous work on the thermal etching of (100) surfaces of NaCl single crystals is extended to the other surface orientations by using polycrystalline samples. The results obtained with (110), (111), (520) and (144) surfaces are used to corroborate the correctness of the mechanisms proposed in a previous paper to explain the thermal etching in air of (100) surfaces; it is also shown that these mechanisms are only dependent on crystal structure and not on the surface orientation.When such surfaces were treated with wet silk, concentrated HC1, and Moran's reagent, a very different behaviour was observed for each orientation. The reactivity is very sensitive to crystallographic orientation, being very low in the case of the (144) surface. 相似文献