Pulsed operations can be used to improve the efficiency of light-emitting diodes (LEDs) on human perception. We conducted an experiment asking 46 observers to compare the brightness of a viewing area that was separated into two similar parts and illuminated by both pulse-modulated LEDs and DC-driven LEDs. Using filters, we eliminated the influence of color shift on human perception. The results show that the efficiency improves more when the duty ratio decreases. In addition, the perception enhancement has a linear relationship with duty ratios ranging between 20% and 80%. When the duty ratio is close to 100%, there is almost no effective enhancement.