Power-LED Heat Dissipation Design And Packaging Research

The semiconductor lighting is an industry that saves energy and is widely used.With the increasing demand for power-LED devices in the market,the research on packaging and heat dissipation of LED light sources is becoming more and more important,which is a key technical point for realizing rapid development of the industry.In this paper,the power-LED light source chip-scale package is designed,and the white light source with good performance is obtained through testing.Besides,the finite element simulation software is used to optimize the size and structure of the dissipating fins,and form a complete heat dissipation system with the white light source of the flip-chip package.The main research work is as follows:Firstly,through the review of domestic and foreign literature,the LED development history and research status have been deeply understood.The light source packaging and heat sink optimization are determined as the research focus.Starting from the principle of LED illumination,the three structures of the chip’s dressing,flip and vertical structure of the chip are deeply analyzed.Outline the development of packaging and introduce thermodynamic theory.Then,the power flip-chip LED light source package design optimization.Integrated design of flip-chip LED chip layout and ceramic substrate layout achieve uniform current distribution on the chip surface;Good welding results are achieved by optimizing the reverse welding parameters(including the temperature of the ceramic substrate and the pressure value of the weld).Good soldering performance is that the chip has a pushing force greater than 2kg from the substrate,and the surface of the chip that is pushed open has a good soldering surface;By optimizing the phosphor coating process(optimizing the distance from the lance to the chip plane),a uniformly distributed phosphor layer can be obtained;After verification of the number of times of spraying,it is possible to accurately control the color temperature of the light source according to the setting of the number of spraying times;From the test data of the light source,it can be obtained that the light source has good photoelectric parameters: light efficiency over 120lm/W,illumination angle 120°,thermal resistance 4°C/W.Finally,the heat sink fins are dimensioned and structurally optimized.The light source of this design was used as the heat source,and the ANSYS finite element software was used for thermal simulation.The fin substrate thickness was determined to be 5mm by simulation analysis under the condition that other dimensional conditions were constant.On basis of the determining the thickness of the fin substrate,the fin thickness is divided into three types: 1mm,1.5mm and 2mm.Each fin has five intervals of 2mm,3mm,4mm,5mm and 6mm.Then,the established model is simulated,and the simulation results of different models are compared to obtain a heat sink with outstanding heat dissipation effect;On basis of the optimal size heat sink,the length of the fins is optimized,and the optimum value of the fin length is obtained by combining various factors.After the fin size parameter optimization of the heat sink is completed,the heat sink structure design is continued to further improve the heat dissipation performance.