A quick FAQ about the common questions about PWM flicker, because sometimes it may be confusing with all the information out there.

Write me somewhere if your question is not answered and I will answer it and add the answer here 🙂

Do my monitor flicker?

Most of the time yes. This depends on whether your monitor uses PWM or DC dimming.

What is PWM flicker?

Some manufacturers use pulse-width modulation to control the brightness of the monitor.

What is Pulse-width modulation?

Basically turning the LED on the backlight ON and OFF.

Why is this unhealthy?

Your eyes start to contract like this

And you get eye strain and eye pain.

How to fix this?

Set your monitor Hardware brightness to 100% using your monitor buttons.

Why set my monitor Hardware brightness to the MAX?

Most monitors don’t use PWM at maximum brightness.

What happens if my brightness is set to 80%?

Your monitor may use PWM

What happens if my brightness is set to 50%?

Your monitor may use PWM

What happens if my brightness is set to 100%?

Your monitor probably is not using PWM and you don’t get this ON and OFF thing and eye strain.

Isn’t 100% brightness unhealthy?

Yes if your room lighting is really low.

Why is this unhealthy?

For best eye protection and least amount of eye strain and eye pain, your monitor should not look a light source in the room.

It should match the brightness of the room and not look like a light source.

100% brightness in dark room is bad?

Yes.

And with 50% brightness, I may get even more eye pain?

Yes, if your monitor uses PWM.

Then what to do?

Iris can control the brightness of the monitor without using PWM.

I don’t want it, what else?

Turn ON the lights in the room all the time and use your monitor at maximum brightness.

I like a dark room, what else?

You can buy some new monitor which is flicker-free or use Iris.

So I should use Iris at maximum brightness?

No, Iris brightness is healthy and doesn’t use PWM.

You can use whatever value you want with Iris, but your monitor hardware brightness from the buttons is good to be at 100%.

Ideally, match the brightness with Iris to your room lighting.

So I will not get eye pain if Iris is set to 50% brightness?

Yes.

Will I get eye pain if Iris is set to 40% brightness?

No.

Will I get eye pain if Iris is set to low brightness?

If your room is really bright and your monitor brightness is dark you may get eye pain.

Try to match the room lighting to the brightness of the screen.

If brightness is set to 150% from Iris will I get less flicker?

It will be the same as any other value.

Iris can’t change the hardware but can remove the PWM flicker when controlling the brightness.

When backlight Hz is lower there is more eye strain?

Yes, you have bigger breaks between ON and OFF and your eye contracts more.

When backlight Hz is bigger you get less eye strain?

Yes, you have really small breaks or there are just no breaks in the light and your eyes don’t contract.

What is our goal for Eye health?

Basically, our goal is to have a constant light level which is not possible with LED or the highest possible Hz rate with LED.

Lower Hz rate is like turning the lightbulb in the room ON and OFF all the time.

Is no flicker 0 Hz frequency?

No, we call flicker this ON and OFF.

Basically, in monitors, you strive for the biggest possible Hz for lowest eye strain.

In E-ink, you have 0 Hz frequency but the technology is different.

0 Hz is no flicker but you can’t have this thing with any light source.

You can get 0 Hz from a book or some physical object like a rock.

I’m confused, what to do?

Set your monitor hardware brightness to the MAX from the monitor buttons and use Iris to control the brightness.

Should I quit monitors altogether?

Well, this is the best solution but it is really hard in our world of technology and electronic devices altogether.

Are flicker and EMF connected?

Well, both came from electrically charged objects but there is no big connection.

Do all monitor use PWM?

No, but a lot of them, the other monitors use something called DC dimming.

What is DC dimming?

Instead of using short breaks to control the brightness like this

You change the DC like this

And this doesn’t cause flicker.

So DC dimming doesn’t flicker?

Well, there is subpixel flicker and all kinds of other stuff but it doesn’t use PWM to control the brightness.

DC dimming is better than PWM.

Do Iris does the same as DC dimming?

Yes, but Iris changes the contrast a bit so DC dimming is better.

However, if you don’t want to spend a lot of money for a new monitor and want automation Iris is better.

Anything else?

Try Iris for a couple of days and see if it helps you with eye pain and sleep problems.

If it doesn’t you can always uninstall it with 2 clicks.

Daniel Georgiev
CEO Iris Technologies

Publishing date: 15.05.2018

The post What I need to know about PWM flicker? appeared first on 💡👨‍💻 Iris - Software for Eye protection, Health and Productivity 🛌👀.

Iris is fixing this by controlling the brightness with the video card and by changing the white point of the monitor. This ensures that your backlight is at high frequency even at low brightness levels.

The best solution to this problem is to actually use E-ink device. Other solution is to buy flicker-free monitor. Using flicker-free monitor or using Iris is basically the same, but nothing can replace using E-ink or not using electronic devices at all.

The post How Iris reduces PWM flicker? appeared first on 💡👨‍💻 Iris - Software for Eye protection, Health and Productivity 🛌👀.

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.

The post How Iris reduces PWM flicker? appeared first on 💡👨‍💻 Iris - Software for Eye protection, Health and Productivity 🛌👀.

The interesting thing about monitors is that they should be like the Sun.

The second interesting thing about monitors is that they should be like a lightbulb.

They failed at both of this…

Monitors

Monitors are like the Sun. They emit all colors of the rainbow but as you can guess it’s probably not so normal to look at the Sun at night.

But unlike the Sun, monitors don’t emit full spectrum sunlight.

Sunlight

At the picture above you can see the light spectrum of the sun.

Notice how blue, green, yellow and red light are almost equal. We need this kind of ratio and this is embedded in our biology.

Yes, the Sun emits also UV light, but our body is attuned to UV light and produces important substances like Vitamin D when we get it from the Sun.

Direct UV light exposure to our eyes is also not so good, but UV light is stopped at the front of our retina while blue-violet light enters deep into our retina and may cause macular degeneration in the long run.

At the picture above you see the light specters of different light sources. The light emitted from the sun is like the first graphic while the light emitted from monitors is like the third graphic.

Notice how much blue light the LED lights emit and how little green light.

The problem is not actually the blue light, the problem is the ratio and that red light is almost missing from our monitors.

We can somehow fix this by reducing the color temperature of the screen, but the red light never becomes more and this is why we need more red light exposure.

If you read about this, red light is actually one of the most important lights. Science has proved that plants grow way bigger when they get a lot of red light and low amount of blue light.

In humans, blue light regulates our mood and it’s important also, but at night it stimulates our melanopsin photoreceptors in the eyes, our melatonin secretion stops and we can’t fall asleep if a lot of blue light is present around us.

The standard Incandescent Edison light bulbs are good at producing blue light, but they again fail in the morning when we need blue light to lift our mood.

The thing about sunlight is that not only it’s full spectrum light, but it also changes during the day and night. Well, there is actually no light at night, but still.

Our biology has evolved for millions of years to work together with this shift of light and we also need this change.

In our modern lifestyle, it’s best for us to try to replicate this gradual change with programs like Iris which tries to replicate the Sun spectrum change.

Light bulbs

Monitors are like a light bulb. But instead of one light bulb, we have millions of them in the size of several inches.

In order to reduce their energy use and brightness, you need to turn them ON and OFF hundred of times per second.

And this thing, this ON and OFF thing is called flicker.

Our brain is slow and we do not perceive this, but our eyes are fast and our iris starts to open and close like this

Of course, the amplitude here is much bigger to show the effect since the flicker rate of the monitor is much faster but basically, our eye starts to contract like a muscle.

You can test this by turning the light in your room ON and OFF fast and take a video or look in the mirror.

The science behind this thing is that in dark we need more light and our pupil is dilated.

When there is a lot of light around us or there is lots of daylight our pupil is undilated.

This is how our eye controls the amount of light entering it.

You may be thinking why do the monitors need to turn ON and OFF and why they can’t just glow all the time, but it’s not that simple.

LED lights will use a lot of energy if they are constantly ON and they may also overheat. Same goes for other monitor types.

The bigger problem is actually that the lower the frequency of this flicker and the bigger the breaks between these 2 states, the more energy-efficient the monitor is.

Energy efficiency sells. Better battery life sells and this is why manufacturers prefer to make low backlight frequency monitors.

This is why manufacturers use cheap and energy-efficient methods like Pulse-width modulation to control the brightness of the monitor.

The problem is that the lower the frequency of this flicker the bigger is our iris contractions and the more we feel eye pain.

One of the best ways to fix this problem is to just use E-ink devices but they are slow for real-time images.

We need new kinds of technology and new kind of monitors which change the colors fast without flicker and without excessive blue light.

Some flicker-free monitors actually still flicker but they flicker at a higher frequency which is better for the eyes.

The ideal flicker-free monitor has a constant voltage applied to the backlight.

PWM flicker

Pulse Width Modulation (PWM) is a method to control the brightness of your monitor by settings the backlight ON and OFF at high frequency.

Our brain doesn’t perceive this, but we get a lot of eye strain and headaches from this.

If this done at the really high frequency it’s not so unhealthy, but the problem is that the lower the brightness of the monitor the lower is the frequency of the backlight.

This is just an introductory article and I’m not going to get into more details, but what you need to know is that at maximum hardware brightness from the monitor buttons there is no PWM and your eyes will hurt less.

LED monitors with PWM at minimum brightness in slow motion look like the video below

CCFL monitors with PWM at minimum brightness in slow motion look like the video below

You may think now then Why is PWM used and the answers are actually really straightforward.

Why is PWM still used?

PWM is really easy to implement in a hardware circuit. You only need to switch the backlight ON and OFF fast.

PWM gives a wide range of brightness and luminance reduction while flicker-free monitors are capped at certain minimums and maximums.

PWM is energy efficient and requires less battery life.

Solutions

There are 2 good solutions to the PWM problem.

The first one is to buy a flicker-free monitor. Flicker-free monitors use something called DC dimming which doesn’t make the backlight to flicker but has a limited brightness reduction range.

Your second option is to use Iris which uses the video card to reduce the luminance of the screen. This changes the colors a bit, but for people who don’t need exact colors of the screen, it’s cheap and effective solution.

Now let’s look at both solutions at more details.

Flicker-free

Flicker-free monitors use DC dimming and don’t flicker. The current going to the backlight looks like this

Since they don’t use PWM they also have limited brightness reduction range.

Flicker-free monitors are much more expensive since the DC dimming circuit is more expensive to implement.

They are also not as energy efficient as the PWM monitors, but they preserve the colors even at minimum brightness.

Iris

Iris is software that can reduce the brightness of all monitors without PWM and without changing the backlight flicker-frequency or the current through the backlight.

It does this by using the video card to move the white point of the monitor. This gives you a really big brightness reduction range.

Iris can also gradually adjust your screen brightness depending on the time of the day so your screen will match the light around you at night.

Iris is a cheap and effective solution for reducing the negative effects of monitors with PWM flicker.

By controlling the brightness without PWM, Iris helps with eye strain, dry eyes, and headaches caused by PWM flicker.

Overclock your Monitor

On some laptops with old Intel HD Graphics graphics card and drivers, you can also control the PWM flicker Hz of the backlight to make it higher and more healthy.

Iris has this feature called PWM control integrated but hidden by default since this can damage your monitor if you set the frequency too high.

Recommendation

1. Set your monitor Hardware brightness to 100% using your monitor buttons.

2. Use Iris to control the brightness without PWM

Final Words

If you liked this article share it with friends. You can also try Iris, which is software for eye protection and better sleep.

Iris will automatically control your brightness depending on the time of the day and try to match it to the light around you. This will help you feel less eye pain when you use your computer.

The program also controls the brightness of your screen without using PWM. This will help you to use your computer for longer periods of time without feeling eye strain or headaches.

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The post How Мonitors Destroyed our Eyes? appeared first on 💡👨‍💻 Iris - Software for Eye protection, Health and Productivity 🛌👀.