A Study on the Effects of LED Light’s Pulse Width Modulation on Work Concentration

Abstract

This study examines the effects of changes in LED lighting on a subject’s work environment by varying the characteristics of LED light provided to an experimental work environment while subjects complete an error correcting activity. The study configured a variety of lighting environments using an LED lighting control system, through which the control of pulse width modulation (PWM) and illuminance can be conducted. For the indoor environment of the test bed, the comfort index in winter recommended by ASHRAE Standard is applied. The nine types of lighting environment are configured, according to PWM and illuminance. Concerning the configured lighting environment, the PWM ratio is set as R:G:B = 1:1:1, R:G:B = 4:1:5, R:G:B = 8:7:7, and illuminance is set as 400 lx, 700 lx, 1000 lx. This study also analyzes the change of subject concentration levels through real time measurement of brainwaves, while the error search and correction is carried out in the suggested lighting environment. This was analyzed through relative SMR analysis. The experiment did not find significant differences in concentration levels resulting from the different lighting conditions.