How Iris reduces PWM flicker?

Medium size explanation

How modern monitors work?

All monitor have some kind of flicker rate. This is normal, because the way semiconductors work requires them to turn ON and OFF in order to work properly. Every modern display uses some kind of LED, OLED, LCD and every other monitor technology used today.

The only way to completely eliminate the flicker from your electronic devices is to use E-ink or to not use electronic displays at all.

The flicker is not the actual problem. On maximum brightness most monitors have flicker rate with really high frequency and the iris of the eye will not start to synchronize with the ON and OFF cycles of the backlight.

The problem is PWM or the so called Pulse-width modulation and let me explain why.

The goal of monitor manufacturer is to make energy saving and cheap monitors. Well the solution to make the cheapest and the long lasting monitor is to use PWM to control the brightness. Basically this means that to control the brightness you make the flicker frequency of the monitor lower and you get not so bright display.

If you want to make it cheap you need to use PWM, if you want less power consumption you need to use PWM. If you need even less power consumption you lower the frequency of the backlight even at maximum brightness.

This is bad. For the eye it’s like turning the lights in your room ON and OFF hundred of times per second. Go and try and see the eyestrain after only a minute.

How Iris works?

Well to fix this problem I created special type of brightness reduction into Iris. Iris is using the video card to control the brightness. Basically instead of changing the frequency of the backlight, Iris is changing the white point of the monitor.

Yes, this will make your colors look a little bit more darker, but you will not feel eye pain. It’s not cure for everything and the best possible solution will be for me to start to make E-ink monitors, but it’s better than changing the flicker frequency.

The second good thing about Iris brightness is that it will not change contrast of the screen. You can achieve something similar by placing black transparent overlay on your screen, but this way you will change the contrast of the screen and it will be harder to read on it.

Are there any other solutions?

You probably have heard about this new flicker-free monitors. Well they are not exactly flicker-free. They just use something called DC dimming instead of PWM.

Direct current dimming is what the modern flicker-free monitors use. The design of the circuit is more complicated and they are more expensive. They are not energy saving also. Both Iris and flicker-free monitors do the same thing.

Flicker-free monitors still flicker, but they flicker at high frequency at both high and low brightness levels. At maximum brightness cheap monitors and flicker-free monitors are basically the same.

The Pro of flicker-free monitors is that even at minimum brightness the colors of the screen are calibrated and accurate.

The Pro of Iris is that it costs less than a sandwich and the basic things are actually in the free version which you can use forever for free.

Posted in Articles, PWM