What is “Flicker” mean in LED monitor?


“Flicker” is inevitable in LED Displays because it is related to the LED backlight technology, LED’s brightness can be controlled by adjusting the current intensity so we call this is the analogy dimming modulation. But the LED’ color will have some change when the current strength is up or down. This problem has no impact in our normal using when we need to light up somewhere. So it is the general using in LED lighting. But LED for high end using like in monitor display, color shift is unallowable because customer need more colorful and lightness leaves to see a picture or entertainment using. For this reason it needs another backlight technology to solve the color missing problem. For now on, LED monitor all most us the PWM modulation to control to control monitor’s light grade. But it cause another problem is “Flicker”, and it is more easy to see when we reduce the brightness.

PWM (Pulse width modulation) is a technology that using digital to control analog signal output, it commonly used in the buzzer, electric, motor, fan speed and light control.

PWM is set the LED lamp power on or off in high frequency in 200 times/ sec (200hz) that human eye can’t easy to find. If we want the 25% backlight, we put the brightest time to 25%, dark to 75% in quick repeatedly turn on and off while we will see the 25% bright.

So the lamp always in the on and off situation and keep the frequency over 100hz ~200hz to avoid people see the flicker. Although the frequency over 200hz human can see the flicker but it still cause a damage of our eyes, because our optic nerve still work to get with flash frequency change from black to white, which can cause our eyes tired.

Here's how you test your monitor with a smartphone, it's really that simple.

Some of my office monitor still use CRT and their flickers at 50hz really make me mad. I'm glad gone are the days of CRT monitors.

I do miss its color, contrast, gamma, non-existence input lag, blur free (Nvidia ULMB can simulate flicker for that!)

I don't miss their heat, radiation and that flickers even at 80hz.

CRT monitors, darn those really can give headache.

Home CRT is fine but if your work place gives you an old CRT - man, tough luck staring at it for hours a day.

Really dinosaur la those company which still using CRT...

Thanks for the sharing guys!

Anyway, check out the video below (from 0:30 onwards) for using a table fan to test screen flicker.

Good thing I only need to use those monitor twice a year...