Characterization of the stroboscopic effect for OLED displays using the PWM dimming method

Organic light-emitting diode (OLED) displays have been widely used in smartphones in recent years. Manufacturers use the stroboscopic visibility measure (SVM) to characterize and compare the performance of OLED displays using the pulse-width modulation (PWM) dimming method in producing perceivable flicker, although the SVM was developed for lighting products. This study investigated how the dimming frequency and display luminance of an OLED smartphone display affected the stroboscopic effect by presenting an oscillating arm in front of the display. The results showed that the stroboscopic effect was visible when the dimming frequency was 480 and 960 Hz with the display luminance below 40cd/m², and when the dimming frequency was 1440 Hz, with the display luminance at 5cd/m², the threshold of the duty cycle was around 50%. When the dimming frequency was 1920 or 2160 Hz, the stroboscopic effect was invisible. The results also suggested that for OLED displays, the SVM may still be used, but an SVM of 1.5 to 2 can be used as a conservative threshold instead under the experimental conditions.