| Summary: | 碩士 === 國立成功大學 === 工程科學系碩博士班 === 98 === In accordance with the improvement in its luminous efficiency, light emitting diode(LED) has been gradually developed with functions of high power, good reliability, long life, multiple purposes and low power consumption.As a result, the array LED has been broadly applied in human livings nowadays.
This study applies the ANSYS finite element analysis software to analyze the thermal behaviors of the array LED. The array LED is modeled by 4 same-size LEDs with metal core substrate on a heat-sink. The air natural convection coefficient is obtained by the Flotran heat flow analysis. Thus, this value of the convection can be verified through the iterative method since such convective value is set as the boundary conditions of the ANSYS thermal analysis to obtain the temperature distribution in which the chip junction temperature and heat-sink temperature are conformed the requirement of the C2-121 product.
Prior to the process of the optimal design on the chip junction temperature, the most significant parameters are chosen by the fractional factorial design method. The regressive models are set up by the double response surface method and the mixed response surface method respectively. Furthermore the genetic algorithm combined with the response surface is applied to obtained the optimal design parameters, then the results obtained by both two methods are discussed. Afterwards, a mixed response surface method is applied to analyze the interactive effects among various parameters on the chip junction temperature. Finally it is found that the metal core substrate thermal conductivity and the heat-sink height are the most significant factors. Besides, the interactive effects between the size of chip and the thermal conductivity of the chip adhesion layer are the most obvious effects on the chip junction temperature.
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