Research On Phosphor Coating Process And Cooling Technology Of High-power White LED

White LED lighting had become a newly high technology with great economic and social importance in the world. The packaging technique of high power LED lighting was focused in this thesis.In the first chapter, the development of LED lighting in the world, the structure and mechanism of white LED, and packaging process applied currently, especially the coating technique of phosphor for high power white LED and its limitation, were reviewed.The matching of the spectra between blue LED chip and yellow phosphor was then evaluated so as to improve the conversion efficiency and the output light quality of white LED lighting. The measurement of the emission spectra for the LED chip, and, the emission and excitation spectra of the phosphors was carried out to optimize the conversion efficency of white LED lighting.A novel technique for the coating of phosphor was proposed, and then adopted to obtain a phosphor layer with controllable and uniform shape ,which was developed by using of fumed SiO₂ particles. New kind of mould and a switch were made by ourselves which controlled the chip up or down. Therefore high power LED samples with the phosphor layer of uniform thickness and shape and excellent performance were achieved. The effect of the fumed SiO₂, organic resins, shape of the phosphor layer and the phosphor on the performance of LED lighting was discussed in details.Based on the heat transfer theory, a theoretic simulation was conducted .With the finite element method, a model of LED lighting was adopt by the Ansys software. The result of LED lighting was influenced by the structure, material and processing of the packaging.According to the result, a ceramic plate was made and compared with the Al plate for the effect of heat transmission.