Abstract
This thesis conferring LED that operates in full power and nature convection circumstance. By changing the different arrangements, we hope to improve its performance, less junction temperature increase and less influence on total luminous flux. If possible, we hope to decrease the number of LED, and still maintain its own regulation specifications, achieving the purpose of energy saving, extending its life and cost down. The method for analysis is using datasheet on internet which is supplied by LED manufacturers. The datasheet has to include three important parameters that relate to thermal, electrical, and optical properties, and its optical spectrum distribution diagram. The three parameters is TSP (it is a coefficient which stands for the relationship of thermal-electrical coupling), the decline curve illustration that describes the increase of temperature, and the decrease of luminous flux, and the directly proportional coefficient to the red shift of dominant wavelength when the temperature is increasing. After finishing thermal-electrical coupling iterations till convergence, one can get the reduction of luminous flux and the change of mixing color that represent by correlated color temperature Hoping this analysis method of LED arrangement will achieve the aim of cost down by decreasing the number of LED. With simulation and programming, we can obtain the result that under such difficult conditions, if we can decrease 3W LED from 15 to 14 by pulling up the lager distance of structure(for example: from 0.5cm, 1cm to more than 3cm, like 4.5cm,7cm, or 10cm). Also we hope this method which can find out the limit of number decreasing and the distance it should has would apply to illumination which owns more power or fewer heat dissipation area.