Impact Of Microstructures By Femtosecond Laser Direct Writing On The Led Efficiency

We report on fabricating microstructures on the surfaces of LED chips by femtosecond laser direct writing. The changed trend of LED light extraction efficiency with the variation of the laser power and pulse was studied. It is found that there is an optimal surface treating condition (laser power and pulse number) in fabricating the microstructures on the surface of the LEDs to make the LED luminous flux maximum. In our experiment, the luminous efficiency of LED is close to the optimum enhancement value when the LED was surface structured with a laser power of 0.48 mu W, three laser pulses at one point and the point spacing of 5 mu m. In this condition, it can be improved by 23.53%.