| dc.description.abstract | This thesis is mainly focused on developments of new technology of thermal dissipation design and measurement using nano-materials, as traditional methods of temperature measurement are not direct non-destructive ways measuring the inner temperature of the chip, and it’s not easy to know the real inner chip temperature using infra-red thermal imager since only temperature of partial surface can be measured. In this thesis we put forward a new method to calculate the internal chip temperature via thermal conductivity or property of materials. The actual internal LED temperature distribution is calculated by using of heat transfer principles such as characteristics of isothermals, as well as conversion to the equivalent circuit. Experimental data are measured in constant temperature environment to improve the accuracy of measurements. Voltages and currents are provided via the digital power supply. Long-term multi-point voltages values are recorded via thermocouple combined with NI CompactDAQ data interceptor, and then are inputted to a LabVIEW graphical programming platform and are finally converted to Celsius temperature data with a LabVIEW program developed by the author which simplifies the process of complex computing as well as reduces the calculation error.
During the experiment of the effect of thermal dissipation, we found that within the same period of cooling time, liquid nano- materials are better than silver conductive plastics by a temperature difference of about 2℃, and better than nano-powder materials by a temperature difference of about 4℃. So the liquid nano-materials are with better heat conductivity and convection, and nano-powder materials are with poorer performances as a result of irregular arrangement. Although silver conductive plastics are good in heat conductivity, they are poorer in heat convection. It’s a major breakthrough in nano-technology using nano-liquid materials as the heat carriers to increase the effect of heat dissipation of LED.
Nano-liquid materials with the temperature monitoring system mentioned above will not only enhance the heat transfer performance, increase the thermal conductivity, lower the costs, but can also directly calculate the internal chip temperature. This technique can be developed into a 3D temperature measurement system used in IC packaging industry in the future. We also confirmed that the actual temperature within the chip can be measured by the combination of heat transfer theory and the material properties. This system will be upgraded into a small error, rapid calculation system of the temperature measurement.
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