Thermal Performance of AlN-Coated High-Power LED Optimized Using Taguchi Statistical Approach

Effective cooling leads to the integration of nanoscale coating and electronic components in light-emitting diode (LED) modules, because their excellent heat dissipation capacity and low thermal resistance strengthen their performance and reliability. This study analyzes and compares the electrostatic spraying process of aluminum nitride (AlN) ceramic substrate preparation methods (thin-film, thick-film, crystal structure, and AlN ratio) by scanning electron microscopy and x-ray photoelectron spectroscopy. High-power LED cooling modules are used in the Taguchi method for the cooling effect of the Cu and Al substrate temperature. Heat flux characteristics are established through the optimal design of the LED module temperature to obtain the optimum factor levels. The optimum LED assembly arrangement is 0.3 W × 4, made of an Al substrate, at a temperature of 180°C, thickness of 5 mm, spraying time of 20 s, reciprocating speed of 55 mm/s, spray flow rate of 3 cc/s, resin:AlN ratio of 1:4, and baking time of 25 min. The study results, according to the L18 orthogonal array of the optimal design module, showed that the difference between the maximum and minimum average temperatures was 4.83°C. The variance analysis showed the significant effects of the LED module temperature factors. The percentage contributions of the resin:AlN ratio, material, spraying temperature, reciprocating spray speed, and thickness are 41%, 16%, 12%, 11%, and 10%, respectively; these five factors accounted for more than 90% of the total significant effect. Additionally, the optimal design and commercially available 7.2-W power modules are compared; the average substrate temperatures were 66 and 82°C, respectively, and the luminous flux was 1499 and 1250 lm, respectively. The Taguchi statistical approach can effectively enhance the heat dissipation efficiency, provide high heat transfer capability and rapid cooling effects, and improve the crystal quality of AlN. Its application can hence achieve process simplification, precision design, easy production, and green production processes.