Fabrication of micro-lens array by means of ion wind for chip-on Board (COB)

Light-emitting diode (LED) lamps, regarded as `green lighting' fourth-generation light sources, are applied widely to many applications around us. Meanwhile, the chip-on Board (COB) packaging is a fatal important kind of packaging method for LED, with many advantages, such as bigger optical power, more compact size, loss manufacturing cost, and good reliability. However, low light extraction efficiency (LEE) is one of the most challenging points for the COB packaging. In this paper, a method of fabricating micro-lens array was proposed based on the ion wind generation. Using this method, fabricating of micro-lens array, the structure of the micro-lens array can be controlled through the process of adjusting the parameters of the ion wind generation, such as changing the voltage or the distance between the electrodes. As a result, the experimental results show that the light extraction efficiency of COB improved obviously, increasing the light extraction efficiency to 8.24%, 6.36%, 8.59%, 5.94%. This method of fabricating micro-lens arrays would be a potential way in improving the LEE of COB with high luminous efficiency.