Effective Illuminance Improvement of a Light Source by Using Pulse Modulation and Its Psychophysical Effect on the Human Eye

By using Blue, Green and Red LEDs it is shown that the Broca-Sulzer effect holds for a continuous pulse operated LED lighting system. The effective enhancement at 5% duty ratio and frequency of 60 Hz is between 1.01 to 2.22 times that of DC operation although this is not as high as it is in the single pulse discharge lamp case. However, this result shows that there is a possibility of improving the efficiency of an LED and a PWM circuit for pulsed operation for developing a highly efficient lighting system.