Computer Display Monitor

Today computer monitors are safer than ever. But we have to expect that technology is in a continuous improvement. On of the most important things in computer is the display backlight. Display backlight has been improved a lot, especially to use less energy.

There are a lot of benefits of the new LED light monitors the old CCFL (fluorescent) backlights. But, many people say that they experience unusual eye strain, pain and headaches with their new computer monitors. Well, the main idea is that we use to much the computer, but it is not all about that!

How LED and LCD Monitors Work?

I bought an LCD computer monitor that should be hundreds of time better that the old CRT monitors. Unfortunately the new LCD computer are not flicker free! The old CRT monitors redraw the whole screen many times a second, this is determined by the refresh rate. The new LCD monitors draws a constant image. But in order you to see the image it has a backlight source that is used to flicker so you would see the image on the screen. So the matrix itself doesn’t flicker at all, it’s the refresh rate.

Pulse-Width Modulation (PWM)

Basically this flickering occurs when the brightness is reduced from 100%. For the backlight to be dimmed it has to flicker! This is called PWM (Pulse-Width Modulation). So when you make your brightness darker it will cause the monitor to flicker. By flickering it means that the backlight does stop and then lights up. See the image bellow:

PWM LLed Backlight Flicker

More stops, means that the brightness is lower. The only way to stop backlight from LED flickering is to set it at 100%. Unfortunately no on can work with the backlight at 100%, it is also a pain for out eyes.

In the video bellow you will find a Flickering test that you can even try on your monitor. The LED flickering is more noticeable when dropping the monitor contrast bellow 60%. The test is between, Dell U2412M (LED Backlight) monitor with a 2007 iMac, and a 2002 Cinema Display (CCFL backlight).

Other way to test you monitor, is to open your phone camera app in video mode and look through your phone at the white computer screen. You will see horizontal lines traveling your monitor.

Flickering Monitor

Does PWM Really Cause Eye Strain and Headaches?

Pulse-width modulation (PWM), is the technology used for dimming the LCD backlights. The flickering persists, but you don’t really notice it. PWM is cheap and saves energy, especially when it is on a laptop.

People are affected in different ways, some people have tears when using such monitors, someone has pain after a while, other have headaches time to time. Also doctors say that LED PWM flicker will hurt your eyes and can affect you  nervous system other the time.

Solutions and Recommendations

The best recommendation is to use less time your computer. Other thing, is that many people dim their display almost to minimum, thinking that there will be less light from the monitor and will not cause any trouble. Actually that is wrong. The more you dim the display the more flickering it causes.

You have to adjust your computer brightness to the optimal percentage. Also you have to adjust the position on the computer desk and some more things you ca Read Here.

Flicker-Free Monitors

Another great recommendation is to buy a LED Flicker-Free monitor. On the market you will find not too many LED Flicker-Free monitors, but you have quite a nice range to choose from. Manufacturers like BenQ, Samsung, Asus and Dell are producing led flicker-free monitors that are comfortable with your eyes. You can check Led Flicker Free Database from There you will find a big range of LED flicker free monitors.


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