A LED display screen is a full digital equipment which is driven by the impulse current. The Gray-scale and Brightness is realized by PWM (pulse-width-modulation) and the illumination of a LED is a pulse-type. When the frequency of pulse repeating is not fast enough, the human sight would feel twinkling.
Ferry Porter Rule and Critical Fusion Frequency
So, how high the frequency can eliminate the twinkling? Ferry-Porter rule points out, when watching a pulse illumination, coming with the improvement of the pulse repeating frequency, there is a critical point for human eyes. People will feel the illumination continuous, when the frequency is higher than the critical point. That’s we call Critical Fusion Frequency.
Refresh Rates for Full Color LED Screens and LED Displays
A refresh Rate defines how many times the content on the LED display repeats in each second. According to the Ferry-Porter rule, and our experience, to eliminate the image twinkling, the refresh rate for full color LED displays should be higher than 240Hz, and for full color LED displays with a brightness higher than 4000nits, the refresh rate must be higher than 400Hz.
Refresh Rates for Full Color LED Screens for Camera Recording
If there is a camera catching the image and video on the LED display, or when relaying a TV broadcast (LED screens for stages, arenas, events, etc.), it’s necessary to enhance the refresh rate to 2000Hz+. For LED displays and LED screens, it is enough to ensure the smooth image and video with the 50/60Hz Frame-Changing Frequency. And the meaning is not so big to improve further.
Disadvantage High Refresh Rates for LED Screens
As a disadvantage of high refresh rate, the LED display lifetime would be short, to a certain extent.