| dc.description.abstract | In the 21st century, lack of energy or greenhouse effect has become one of top ten problems not only in global but also in many countries for next 50 years in which light is one of main reason that takes a high number of total energy consumption with traditional light equipments like fluorescent lamp and incandescent bulb etc…. When LEDs is invented, it has been used in many fields of living and industry in order to replace for foregoing light since it runs with high efficiency and save more energy. By the advanced technique at moment, it can be expected to reach over 150lumens/W, and as a result it reaches to the luminous efficiency. Because of this, it is essential to study the heat problems as well as the effective of thermal management for white light LEDs.
In this study, the Measurement System of Thermal Resistance and Numerical Analysis Module have been done via experiment and simulation analysis in which focus on the high power LEDs at different work conditions in order to find out better MCPCB structure design and operated condition, that for the purpose of reduce the thermal resistance and junction temperature.
In numerical simulation of the LED device outside thermal-fluid field, there is phenomenon of secondary flow that emerges above LED device when keep the horizontal downward of MCPCB, the velocity of free flow in the vertical angle orientation of device increased nearly 2 times of the efficiency than the horizontal, and the junction temperature as well as the total thermal resistance reduce around by 4℃ and 2.4℃/W respectively. In addition, due to the change of the structure of the substrate（slice, via…）, junction temperature as well as the total thermal resistance reduce around by 4℃ and 4℃/W respectively. Simulation results are accurate more than 90% if compare to the experimental results. On the other hand, in this study the Standard Measurement System of Thermal Resistance has been finished that results are similar and closed to 98％compare with the industry and define the thermal convection coefficient correlation module of LED device by experiment data. These results may give the directions for LED’s design in the future. | en_US |