Heat Transfer Process Analysis And Simulation Of Eutectic Furnace For High-Power LED Encapsulation And Lamps

With the rapid development of electronic information technology, electronic products have been developing towards the trend of high-performance and high-reliability, which leads to higher requirements for the performance of eutectic devices. Eutectic furnace is a special equipment based on the eutectic principle, packaging chip according to different eutectic technological requirements of welding alloy materials under a vacuum or inert gas protection environment. It has the advantages of low empty rate and good heat dissipation, especially for high frequency components with temperature requirements.This thesis introduced the structure of the eutectic furnace body, proposing heating method for eutectic furnace, analyzing eutectic furnace comprehensively on stress, strain and heat transfer finite element with finite element analysis (FEA) and thermal aspects on the packages, that is LED lamps. The chapter one describes the application and package of LED and research on eutectic Furnace recently. The chapter two carries out an analysis on the structure of eutectic furnace chamber with FEA. The results show that the stress and deformation of the furnace chamber mainly concentrated in the bottom arc area and the center of the furnace chamber, meeting the design requirements, moreover further for completing optimization design on the furnace body. The chapter three introduces the whole heat transfer process of high-power LED chip packaging in the vacuum controlled eutectic furnace and its simulation. The simulation results indicate that there is little differences in each time point for the ceramic substrate temperature in the heating process, and reveals of welding chip with good thermal uniformity on the condition that the ceramic substrate temperature difference of no more than±1℃while meeting eutectic furnace temperature. Besides the maximum temperature in the cover outer surface of furnace chamber is 21℃, meeting design demands. Obtaining different substrate temperature curves in different fixtures materials and the same material with different thickness provides a reference for the fixture design. The chapter four simulates the eutectic furnace packaged products, that is high-power LED lighting, in thermal aspect. The simulation analysis shows that four kinds of LED lamps in the same conditions, the higher chip power, the greater the junction temperature, and there is a linear relationship between Junction temperature and ambient temperature. The junction temperature is almost unchanged among the air flow rate 0.001～0.25 m/s. There is significant differences in junction temperature between 14,18 LED lamps with the holes and without the holes, however, there is little differences in junction temperature between 20W,30W LED lamps with the holes and without the holes. Therefore it is indispensable to punch cooling holes on the 14,18 LED lamps. The chapter five concludes design and analysis process of eutectic furnace, also including thermal analysis on LED lamps, looking forward into the development. The innovations in this thesis is not only proposing the structures of high-power LED package eutectic furnace, heating method,but also analysing on stress, strain and heat transfer finite element with FEA.