大功率LED相变封装热沉强化沸腾结构犁削烧结成形机理

High power Light Emitting Diode (LED), a new type of solid-state light source, had exhibited many advantages including energy conservation, environmental friendly and long life time. With the miniaturization and highly integrated development of LED package and application system, the traditional solid heat sink was difficult to satisfy the industrial demand. In this project, a kind of phase change heat sink based on the principle of phase change heat transfer was used for high power LED packaging. The ploughing and sintering method were proposed to fabricate the enhanced boiling structure on phase change heat sink to improve the performance of heat transfer. The three-dimensional structure modeling of heat sink was firstly set up, enhanced boiling structure was then designed under multi-parameters coupling condition, and its mechanism of heat transfer was analyzed by using the numerical simulation method. According to the law of metal flow, both the modeling of three-dimensional micro-groove with multiple-micro-scale microstructure feature and the prediction model of cutting force were established. Forming parameters of three-dimensional burr of heat sink was optimized. Optimal sintering parameters were finally confirmed by experimental method to control the enhanced boiling structure to produce the porous layer. This project will not only provide the independent intellectual property rights in the manufacturing technology of high power LED, but also improve the theory research level of phase change heat transfer components.

大功率LED作为新一代固态照明光源具有节能、环保和长寿命优势，针对大功率LED芯片封装及应用系统的微型化和高集成度发展趋势，传统封装热沉难以满足其散热需求的现状。本项目提出利用相变封装热沉作为大功率LED封装传热器件，采用犁削烧结法在热沉内壁制造三维复合强化沸腾结构以提高其传热能力。通过相变封装热沉三维结构建模，利用数值模拟计算方法对热沉内壁强化沸腾结构进行多参数耦合设计并分析其热作用机理；研究微沟槽犁削成形时金属流动规律，建立表面具有多/微尺度特征的三维微沟槽结构模型和犁削力预测模型并优化热沉内壁三维独立微毛刺成形的工艺参数；研究三维沟槽与铜粉固相烧结成形机理，通过实验研究方法确定最优的工艺参数组合，实现多孔层强化沸腾复合结构成形主动控制的目的。本项目的研究对建立拥有自主知识产权的大功率LED封装热控制元件的制造技术以及对提高我国相变传热器件的理论研究水平具有重要意义。

大功率LED作为新一代固态照明光源具有节能、环保和长寿命等优势，由于其芯片封装及应用系统的微型化和高集成度的发展趋势，散热空间狭小导致高热流密度等致命问题，传统封装热沉难以满足其散热需求。本项目在建立大功率LED相变热沉热阻模型的基础上进行了数值分析得出了影响其传热性能的最大因素是蒸发面沸腾对流热阻，利用计算机优化方法对热沉内壁强化沸腾结构进行多参数耦合设计并分析其热作用机理。项目采用犁削工艺在热沉内壁制造了三维强化沸腾结构以提高其传热能力，对微沟槽犁削成形时金属流动规律进行了研究，优化了热沉内壁三维独立微毛刺成形的工艺参数，建立了表面具有多/微尺度特征的三维微沟槽结构的成形条件。采用固相烧结法在三维强化沸腾结构的基础上得到了沟槽和铜粉烧结的复合强化沸腾结构，同时研究了三维沟槽与铜粉固相烧结成形机理，通过实验研究方法确定了最优的工艺参数组合，在考虑LED封装系统的基础上，制造出了相变热沉样品并进行了测试，与铜质金属热沉相比具有较好的传热性能。在环境温度为20℃，单颗输入功率为10W时，LED基板最高温度为86.8℃。本项目的研究对建立拥有自主知识产权的大功率LED 封装热控制元件的制造技术以及对提高我国相变传热器件的理论研究水平具有重要意义。