my lcd screen is flickering free sample

When TechRepublic first published steps to keep your monitor free from flickers it was 2001, and the computer world was vastly different. Cathode ray tube (CRT) monitors were the norm, and as anyone who has supported a CRT will tell you, they’re far more sensitive than modern LED screens.

That doesn’t mean flickering can’t still happen to a flat screen monitor: Many of the causes of screen flickers are the same in 2018. Some issues, like electromagnetic interference, are things of the past, but these five tips for fixing screen flickers are largely the same as they were almost 20 years ago.

It doesn’t matter if you’re using a VGA, HDMI, DVI, or displayport cable to connect your monitor to a computer: If the cable isn’t securely connected there are going to be issues.

Check the cable at both the computer and monitor ends. If tightening it down or reconnecting it doesn’t fix the problem try replacing the cable with a new one. If that doesn’t fix the issue it’s time to investigate something else.

Monitor refresh rate is the number of times the screen image is refreshed in a second, as measured in Hertz. If the refresh rate isn’t optimal, or is too low, flickering, lag, and other issues can occur.

You can check the refresh rate on a Windows 10 PC by hitting the Windows key, typing “refresh rate” into the search field, and then clicking on View Advanced Display Info. From there click on Display Adapter Properties For Display 1 (or whichever number display is causing the issue).

A video card that isn’t properly seated on the motherboard can cause a lot of problems, including a screen flicker. Turn the computer off and open the case. Find the video card and check to see if it’s properly connected.

If the card is seated on the motherboard properly but the issue persists, a faulty card is likely the issue. Testing this is easy, especially if the problem computer has an onboard GPU that you can plug into.

Power down the computer, remove the video card, and connect the monitor cable to the onboard card or a second video card you’ve replaced the old one with. If the problem persists then the issue isn’t the card–it’s something else.

If everything looks okay it could still be a bad monitor–unplug it and replace it with another one. If the new monitor is working properly you’ve found your culprit.

“It is possible that the complaining end user simply wants a newer or larger monitor and thinks complaining about his or her existing screen will accomplish this,” Detwiler said, adding that there’s a way you can make the user happy and not blow budget money on a new monitor at the same time.

Compared to older displays, LCD monitors are an excellent low-cost, low-power solution to our need for a computer display. Unfortunately, some monitor settings can make an LCD screen appear to flicker.

A flickering LCD monitor is more than just an annoyance. It can cause eye strain, headaches, and a host of other ailments, especially if you spend a great deal of time in front of your computer. Luckily, there are some steps you can take to stop the flickering and avoid these problems. In this article, I’ll show you how to stop your LCD monitor from flickering.

Although your computer monitor may appear to be a still image when no one is using it, it is actually being updated constantly. Much like a film strip is just a bunch of static images displayed quickly, your monitor updates at a fast rate to make it look like things are moving smoothly on the screen.

The rate at which your monitor updates is measured in Hertz. One Hertz is equal to one cycle per second. If your monitor is set to update at a rate of 100 Hertz, then it is refreshing 100 times per second. The Hertz used to measure monitor refresh rates is similar to the Gigahertz used to measure the speed of your CPU, except that Gigahertz is a measure expressed in billions of cycles per second.

If the refresh rate on your LCD monitor is set too low, it can appear to be flickering since there aren’t enough updates per second. While some people are comfortable with around 30 Hertz, others can see the flickering and require a higher refresh rate. The most common refresh rate is 60 Hertz.

The refresh rates that you can set for your LCD monitor are largely determined by the capabilities of your monitor. While some LCD monitors can take advantage of several different refresh rates, others are confined to just one or two.

To choose a new refresh rate for your LCD monitor in Windows, begin by clicking on Start > Control Panel > Appearance and Personalization > Display. If you are on Windows 8 or 10, just right-click on the Start button and choose Control Panel. If you’re in icon view, you can click directly on Display.

Click on the Monitor tab and you will notice a few things. First, notice the setting labeledScreen Refresh Rate. This is the current refresh rate for your LCD monitor. Click the drop down menu and Windows will display all of the refresh rates possible for your monitor.

It is likely that your monitor can only use one or two refresh rates, so this list may not be long. Some manufacturers build monitors that can display anywhere from 30 Hertz to 200 Hertz. Normally, monitors with higher refresh rates will be more expensive. A common refresh rate for gaming monitors is 144 Hertz. If the price of a monitor seems too cheap to you, it’s probably because it has a low refresh rate. For example, some new 4K monitors are cheap, but are only 30 Hertz, which can make everything look choppy on the screen.

From here, you can try a higher refresh rate and see if the flickering stops. Usually this does the trick. If it doesn’t work or there is only one refresh rate listed, there are two things you can try.

First, make sure you are using the latest driver for your LCD monitor. If the driver is outdated or Windows is using a generic driver, the number of refresh rates available may be limited. Visit the manufacturer website and download the latest driver for your version of Windows.

If that doesn’t work, you can force Windows to use a refresh rate that is not technically supported by the monitor. Be careful, though, because it is possible to damage your monitor hardware if you do this.

On the Monitor tab shown above, there is an option that is checked by default called Hide Modes That This Monitor Cannot Display. By unchecking this option, you can force Windows to use any refresh rate for your monitor that you want.

Notice that right underneath this option, Windows warns you about an unusable or damaged display. Uncheck this option and set your monitor to an unsupported refresh rate at your own risk. Depending on your version of Windows, this option may be grayed out, meaning you can only pick from the refresh rates listed in the box.

For Mac users running OS X, you can go to System Preferences and click on Display. Here you can change the refresh rate for an external display connected to your Mac.

If changing the refresh rate doesn’t fix the flicker on the screen, it could be related to other factors. Here is a list of other items you should check:

Input Port – Another solution is to use a different port on the monitor, if possible. For example, if you are connecting using HDMI, try DVI or DisplayPort or VGA instead and see if that fixes the problem.

Surroundings – In addition to hardware issues, electromagnetic fields can also cause screen flickering problems. If you have something else plugged into the same power strip like a heater, fan, etc., try removing it.

Video card – If there is an issue with your video card, it will obviously effect the output on the screen. Update the drivers and open your computer to ensure that the video card is properly seated in the slot.

Hopefully, this will help you figure out what’s causing the flickering issues with your monitor. If you have any questions, feel free to comment. Enjoy!

The monitor is the most visible and often underappreciated part of any computer system. It’s where your movies play, your spreadsheets get displayed, and where your gaming adventures come to life. Over the last twenty years, LCD and LED monitors’ slow but sure development and improvement have put top-quality displays within reach of even the most limited budgets. The older CRT monitors are all but extinct from the marketplace.

Monitor flicker, unfortunately, hasn’t followed CRT monitors onto the ash heap of history. Although the new monitors are far more reliable than the old CRT technology, it is still possible for them to develop a flicker, but don’t panic. If your computer monitor does start flickering, it doesn’t automatically mean it’s the death of that piece of hardware. It could just mean a driver refresh is required or that you or someone else previously made changes to the Windows configuration.

Even though the display on your computer screen looks like a static picture, it’s not. Instead, the image gets redrawn constantly and erased rapidly so your eyes can’t perceive it. If you’ve ever tried to take a picture of an LED monitor, you may have seen some degree of flicker in the form of lines. This scenario is especially prevalent in 60Hz monitors. Regardless, a modern screen can refresh up to 100 times per second or even more with new technology. This action refers to the refresh rate, which gets measured in Hertz. The lower the refresh rate, the more flicker you may experience.

Lastly, the backlighting on many budget-friendly monitors uses PWM (pulse width modulation) for the backlights, leading to more noticeable flickering.

When you look at monitor specifications, you will see a number such as 60Hz, 100Hz, or something else. The number indicates how many refreshes occur per second. On a 60Hz monitor, the screen refresh runs 60 times per second. A 100Hz monitor will refresh 100 times per second. The faster the refresh rate, the quicker the display reacts to changes and the smoother the experience. This outcome is why 100Hz TVs became so popular and why 100Hz computer monitors are ideal for gaming, where the display changes constantly.

Some people are keener to refresh rates than others. A gamer considers a higher refresh rate better for their gaming experience, mainly because a lot of movement and fast action occurs. Some people can run monitors as slow as 60Hz and still feel satisfied, such as businesses that only use the monitor for customer service or office spreadsheets. Other people, like video editors, prefer high refresh rates to produce better clarity in their editing processes.

Many monitors use PWM (pulse width modulation) backlighting techniques, which lead to rapid flickering, even if the eye cannot see it. PWM turns the lighting on and off rapidly and got designed for adjusting LED brightness levels. PWM’s method for dimming backlighting is to change the speed of the on/off action, which creates pulses that make the LEDs appear dimmer. As the brightness gets reduced, the flicker is generally more noticeable. Many monitors on the market use PWM to save money, but there are some bargains on non-PWM models. You just have to do your homework. Flickering generally leads to eye strain, headaches, and more. Overall, flicker-free backlighting helps prevent health issues and improves visual performance.

Check that both ends of the power cable are also secure. A loose power cable can sometimes cause a screen to flicker, and usually, a buzzing sound accompanies it.

If you have recently updated your graphics driver, check the display settings to ensure nothing has changed.Right-click a blank space on the desktop and select your graphics card—NVIDIA Control Panel in this example. The menu option will vary depending on the manufacturer of your video card.

Within the graphics control panel, click on Change resolution. Select the flickering monitor in the options and make sure the refresh rate is at least 60Hz. If you have a 100Hz monitor, set it to that. Save any changes and retest.

Issues with the graphics card can sometimes cause a monitor to flicker. These situations are unusual, but it is a possibility. The problem isn’t your graphics card if you have multiple monitors and only one screen acts up. If all monitors, or your only monitor, flickers, it is worth checking out the hardware and connections.

Ensure that your graphics card does not have accumulated dirt and dust on the surface. Ensure the cooling fan is working and that all case fans are running when they should. Use Speedfan or a similar program to monitor the temperature of your graphics card, as overheating is a prime cause of most issues. If all looks okay, it might not be your graphics card causing the flickering.

The final potential cause of your computer monitor flickering is the monitor itself. You can try testing it by changing the port you are using. If you use a DVI connection, try using the VGA or DisplayPort output. If nothing changes, you may need to borrow another monitor to test or test your monitor on another computer that you know works fine. If the monitor flickers on another computer or with a different hardware connection, then sad to say, your monitor has probably reached the end of its life.

In closing, there are several reasons why a monitor can start flickering. Thankfully, it doesn’t always mean you need to buy a new monitor. Often enough, a simple tweaking of display settings will remedy the situation. Hopefully, these suggestions will help you diagnose your monitor flicker problem.

If your Windows 10 or Windows 11 screen is constantly flickering, it"s likely because you have a troublesome application installed or an unsuitable display driver. It"s time for you to resolve that annoying screen flash.

The problem often begins when upgrading to Windows 10/11 from a previous version of the operating system, but it can occur at any time. We"re going to show you various methods to fix a Windows 10 or Windows 11 flashing screen.

First, you need to establish what might be causing the flickering screen. To do this, open Task Manager by pressing Ctrl + Shift + Esc simultaneously.

Now, watch your screen to see if Task Manager flickers. If it does, along with everything else on the screen, the problem is likely caused by your hardware or a faulty display driver. On the other hand, if everything except Task Manager flickers, the issue is likely due to an application.

If you have a flashing screen, the first thing to rule out is the hardware. Check all the cable connections from the monitor to the computer—take them out and plug them back in to ensure the cables are secure.

If you have a spare monitor cable, try using it instead. Or buy a replacement online, since it"s an inexpensive purchase. Cables can degrade over time, or maybe a pet has had a sneaky chew. Either way, switch the cable and see if it stops screen flickering.

If you can, try a different monitor. If this resolves the problem, you know it"s your monitor that"s the issue. At that point, contact the manufacturer for support or to raise a warranty claim.

A monitor"s refresh rate is the speed at which the screen updates the image per second, measured in hertz (Hz). Basic monitors can usually only handle a 60Hz refresh rate, while more advanced ones—typically aimed at gamers—can go up to 360Hz.

It"s important that you set a suitable refresh rate for your monitor. Sometimes a monitor manufacturer will support an overclocked refresh rate, but this can cause screen flickering.

Use the Refresh rate dropdown and incrementally select lower rates until the screen flashing stops. If the flashing continues, revert to your monitor"s recommended refresh rate.

The screen flashing could be caused by your display driver. You might have an old driver or a faulty new one. Let"s make sure you are running the right version for your system.

You now want to install the latest driver for your system. Windows Update will provide the driver it thinks is compatible with your system. To do this:

If the problem continues, it might be that the newest driver hasn"t patched the problem. If the screen flickering occurred after a driver update, try rolling back to an older version.

Follow the steps above to uninstall the driver, then head to the old driver page for either AMD, NVIDIA, or Intel. This might be a bit of trial and error, but try selecting one released when your screen wasn"t flickering.

If the problem isn"t with your display driver, it doesn"t mean your graphics card isn"t to blame. If your graphics card isn"t seated correctly in your motherboard, it can cause your monitor display to flicker on and off.

You can easily check this if your motherboard has inbuilt graphics. Remove the monitor cable from your graphics card and plug it into the motherboard"s display slot instead. If the flashing stops, you know the graphics card is the problem.

Power off your PC, unplug everything, open the case, and remove your graphics card from the motherboard. Then carefully reseat it, ensuring the card firmly clips into the motherboard. Of course, don"t do this if you"re not comfortable working inside a computer because you might make things worse.

Some apps are incompatible with Windows 10/11 and can cause screen flickering. Think about whether you installed any new software before the screen flashing began or if an app recently updated. In the past, three problematic apps have been Norton Antivirus, iCloud, and IDT Audio.

Across all your applications, make sure you"re running the latest versions. Either update within the app itself or head to the respective official websites and download the most up-to-date release. Alternatively, check the developer"s support page for recently updated apps to see if screen flashing is known as a recent bug.

How do you stop your laptop or computer screen from flickering? Well, many Windows 10 and Windows 11 problems can often be solved by creating a new user profile. Screen flickering is one of them.

As with most Windows 10/11 issues, no one fix will work for everyone. Hopefully, one of the steps above has solved your Windows 10 or Windows 11 screen flashing problem.

If it is time for a new monitor, there are plenty of productive and fun things you can do with the old one. Otherwise, take it off for recycling so it can rest in monitor heaven.

Backlight strobing, commonly known as black frame insertion (BFI), is an effect where the backlight flickers itself to try and improve the appearance of motion. We check for this in a separate test, but the BFI feature is tied into the flicker frequency; the only difference is that the image flicker is during regular use, while the BFI feature is usually something you can turn on and off. Below you can see an example of how introducing flicker on the LG 29UM69G-B helps improve the appearance of motion. However, there are times that the BFI features isn"t good and creates more image duplication, as you can see here.

Manufacturers implement different techniques of pulse width modulation, but one of the more common techniques is shortening the duty cycle. The duty cycle refers to the amount of time the pulse is sent for, and shortening the duty cycle reduces the intensity. Below are two examples from TVs that use different types of PWM, but the same techniques are applied with monitors that use PWM. You can see with the LG that the backlight flickers at all brightness levels, and the difference between the 100%, 50%, and 0% luminosity is the duty cycle. The backlight stays on for less time as you decrease the brightness. The Vizio starts to flicker at lower brightness levels with a short duty cycle, and by the time it reaches 0%, the cycle is almost 0.

A monitor can introduce image flicker at lower backlight levels, even if it"s flicker-free at its max brightness. If you"re concerned that your monitor flickers at lower backlight levels, set the brightness setting to its lowest, and wave your hand (or any object) in front of the screen. If you notice your hand is moving like it"s in front of a strobe light, then it has flicker. Increase the backlight until you don"t see this. If you don"t see this effect, then there"s no flicker.

This test is meant for LED-backlit displays and not OLEDs because they don"t have a backlight. Still, OLED monitors get a perfect 10 because they don"t have any flicker.

LED-backlit monitors have a backlight to display an image on the screen. Sometimes, these monitors will use a technique called pulse width modulation in order to dim the backlight, where it sends short impulses, creating a flicker effect. We want to know which monitors do this and at which frequencies the backlight flickers. Most monitors we"ve tested are completely flicker-free, but there are a few that flicker. Introducing flicker can help with the appearance of motion but may also create eye strain, so having a monitor that flickers or not is entirely up to you.

Some TVs use flickering to decrease the brightness of images by rapidly turning the pixels or backlight on and off. This can produce duplications following moving objects if the flicker frequency doesn"t match the content frequency. Most people shouldn"t notice flicker caused by backlight strobing, but some people who are sensitive to flicker may experience discomfort and prefer a TV with a continuous light output.

Those who aren"t sensitive to flicker can use it to help improve the clarity of fast movement, as shown below. This can be beneficial for sports and video games, because of the fast movement occurring in both. With movies and regular TVs, the low frame rate and the slow shutter speed of the camera during filming mean the video often includes significant amounts of blur intentionally, which can"t be improved through flicker. Intentional blur, however, can be reduced through motion interpolation (also known as the "Soap Opera Effect"), which increases the frame rate of content by interpolating extra frames to make motion look smoother. Motion interpolation and BFI are both methods of motion blur reduction that use different means and produce slightly different results.

The two photos above are from the same TV, the Sony X750H. You can see that the image with backlight flicker is noticeably darker due to the time that the backlight is off. The amount of flicker that a person will find acceptable is subjective. Some people are much more sensitive than others.

True Black Frame Insertion was first proposed by BenQ back in 2006 as a way to reduce blur on computer monitors. The idea was to insert a black frame in between every frame in content that was displayed on an LCD screen, while the backlight remained lit. This kind of BFI never really took off, though. Instead, manufacturers developed techniques like backlight scanning and backlight strobing, which flicker the backlight on and off to create "black" frames.

Backlight scanning tries to emulate old CRT screens by refreshing the image and turning off sections of the backlight in sequence from top to bottom. The idea works in theory but can lead to backlight leakage in between sections of the screen that are turned on and off, which can interfere with blur reduction.

Backlight strobing, on the other hand, strobes the whole backlight on and off at once, matching it to the refresh rate of the screen. As higher refresh rates on TVs have become more common, this method has become more practical. In practice, though, issues can still arise, including noticeable flickering, dimness, and image duplication (also known as "strobe crosstalk").

OLEDs are an interesting exception. Because OLED TVs don"t use backlights and can control each pixel individually, they not only have faster response times that result in smoother images but can also implement a much cleaner Black Frame Insertion, resulting in fewer issues like duplication and headache-inducing flickers.

Are the suddenly disruptive screen flashes of the Android screen flickering issue have you on your toes? Before you sweat a bucket, check out our complete guide on how to fix Android screen flickering issue the easy way.

In the olden days when the software was fundamentally basic and hardware wasn’t top-notch, screen flickering issue almost always meant hardware problem.

Now that we carry mini-computers in our pockets in the form of smartphones, the Android screen flickering issue has become far more rampant with plenty of forums filled with worried customers.

However, the Android screen flickering issue cannot be pointed directly toward the hardware. It may be abnormal behavior in terms of settings and not the phone"s hardware.

Don’t panic! It is not a problem with neither your smartphone not the Android OS. On every modern Android with a brightness sensor when the screen is on low brightness, browsing causes the screen to flicker.

Under normal circumstances, your phone will use the GPU (Graphics Processing Unit) to render images and whatever an app may ask for. However, there are also times when this needs to be done with a CPU (Central Processing Unit) encoder.

And here is where the problems start. If an app can"t "decide" between what it needs to use or if it bugs out in general, switching back and forth between CPU and GPU encoding can create this flickering issue while trying to watch a video, playing a game, or anything similar.

If the Android flickering issue came up after some sort of damage to the device and you don"t know much about hardware, maybe take the phone to an expert.

However, if the display issue came up thanks to a recent update, out of nowhere, or by installing new apps, maybe we can do something about it. Here are a few fixes that you can try and see if they work.

This is a fail-safe feature built into the Android OS. Safe mode allows you to go back to the stock Android device you got out of the box and test out any abnormalities that you’re facing.

When the Android screen flickering issue pops up, you can put your device into safe mode. Once there, check to see if the issue still persists and then diagnose accordingly.

The screen will ask you to confirm if you wish to “Reboot to safe mode”. So, go ahead and press the “OK” button to boot your Android device into safe mode.

This should leave you with only the stock apps - giving you room to see if the Android screen flickering issue is app-related or connected to the hardware.

Apart from all the awesome hidden features offered by Developer options, there are some options in the menu that can help you fix Android screen flickering.

Developer options give you the ability to disable options such as Show surface updates and Disable HW overlays. This is something that can be associated with Android screen flickering issue by several users.

The first tab under the Drawing section should be Show surface updates, so simply press the toggle switch next to it if the option is already enabled.

Basically, the Android screen flickering issue occurs when the system hardware switches between the CPU and the GPU for displaying content on the screen.

By toggling on the Disable HW overlays option, you can physically eliminate the Android screen flickering issue by putting the display operation under the GPU. Just keep in mind that this may increase power consumption which will effectively shorten your battery life.

The exact impact that this setting will have on your battery can greatly differ from device to device. Some phones use mower power-efficient GPUs. But, generally speaking, the GPU is more power-hungry than a CPU.

The Automatic/Adaptive brightness option means that the brightness of the screen changes depending on how much light there is in the room. So when you cover your phone’s photometric sensors, the screen becomes dark and when they are uncovered, the screen becomes bright again.

Since the screen flickering issue in relation to screen brightness is more transient that instant, this might not be the solution you"re after. If none of the above methods work for you, you might need to consider the last resort.

If none of the methods above helped you get the Android screen flickering issue to be resolved, get your phone checked out at a service center. You may have a hardware issue - which means you’ll need to have the front glass panel or the entire display screen replaced.

The exact cost of fixing hardware damage can greatly differ depending on the device. Also on how old it is, the kind of damage that we"re looking at, and also your local store as well.

For example, replacing a faulty display is one thing. Replacing a faulty light sensor or something similar - is another. Some parts are soldered into the motherboard and can"t be replaced at all. In which case, you"ll be forced to get a new smartphone.

If your device is out of warranty and you aren"t afraid to experiment, you"ll find a range of experts on the XDA Developers Forum that have a fix for you. However, these experimental processes need some amount of repairing knowledge and a bit of courage as well, so tread with caution.

You also need to save the device files to avoid them from being accessed when your phone’s screen flashes. Android Data Recovery apps can help in retrieving files on the phone if you aren’t able to touch the screen to operate it.

The software then starts to retrieve the files, you will be able to see their names displayed, the details in terms of size, artists, album, etc. of the music or format of the pictures.

Few things are more frustrating than an Android device when they don’t work, but having an Android screen flickering issue isn’t the end of the world.

In the meantime, you can use the process hoping that Android will release a permanent solution to retrieve data and to get rid of the flashing issue for good. This typical fix for this issue works on most Android devices.

All screens flicker to some degree — be they TV screens, car navigation displays, monitors, tablets, and yes, even smartphone displays. In this article, we will talk a little about what flicker is, what can cause it (on smartphones in particular), and how we at DXOMARK test for it, quantify it, and measure its impact on the end-user experience.

Flicker is a quick oscillation of light output between on and off; it is measured in hertz (Hz) to quantify the frequency at which the oscillation occurs. While we may not be consciously aware of the flicker phenomenon, it’s important to understand that our eyes still physically respond to it — that is, our irises expand and contract in response to these changes in brightness. This involuntary physiological response can certainly explain why we may have a headache and particularly why our eyes can feel tired after looking at a display for an extended period of time — they have been working hard! (This is especially true when looking at a display in dark ambient conditions, such as reading in bed with the lights turned off, for reasons we’ll touch on a bit more below.)

Given the ubiquity of smartphones, it is unfortunate that the flicker on their displays (especially OLED displays) is still an issue for many people. But wait! Why do they flicker? Well, let’s remember that smartphone display hardware is based on either LCD (liquid crystal display) or OLED (organic light-emitting diode) technology. LCDs don’t emit their own light; rather, they are back-illuminated by a strip of LEDs whose light intensity is quite powerful so as to compensate for the brightness drop due to the low transmission rate of the LCD panel (caused mainly by the RGB color filter). By contrast, in an OLED display, every pixel is itself an OLED that produces its own light.

Since both LCDs and OLED smartphone displays are composed of light-emitting diodes, let’s describe how these diodes are driven. Because of a diode’s intrinsic physical properties, it cannot be dimmed by changing the intensity of the current (mA) without impacting the color of the light. So how do phone manufacturers dim displays? They make use of a technique called pulse-width modulation (PWM), which means that they turn the diodes off and on at varying rates. Because we normally should not be able to see this switching between off and on (in other words, the flicker!), our brains are fooled into perceiving the screen as simply dimmer overall (a phenomenon known as the “brain averaging effect”). How dim depends on how long the diodes are off versus how long they are on: the longer they’re off, the dimmer the screen will appear.

So both LCDs and OLED displays power their light sources differently, but both technologies are subject to flicker effect; however, it is usually more noticeable on OLED displays than on LCDs. For one thing, OLED displays and LCDs show PWM at different frequency ranges — the PWM of OLED displays range from ~50 to ~500 Hz, whereas the PWM of LCDs starts at around 1000 Hz or higher. Second, as the human eye may experience flicker sensitivity up to about 250 Hz (at least for most people), it should come as no surprise that OLED displays are more likely to cause eyestrain than LCDs.

An on/off modulation pair is called a period, and the amount of time that the diode is switched on in a period is called a duty cycle. The chart below illustrates how different PWMs affect the perceived brightness of a display:

A significant disadvantage to using PWM technology can be that when a display adjusts to its minimum brightness in very dim or completely dark ambient light conditions, the duty cycle is very short and the interval when the diode is off is proportionately much longer (for example, minimum brightness may translate to a 10% duty cycle, meaning that the diode is off for 90% of the period). At lower PWM frequencies, flicker can become much more noticeable, which helps explain why reading text or watching videos in bed at night is more likely to cause headaches and eyestrain than when viewing screens in brighter conditions.

The video below was shot with a Phantom VEO-E 340L camera at 1500 fps (as were the other videos further below), slowed down to 4 fps to show display pulse-width modulation (PWM) — the white areas separated by black lines that extend across the screen when brightness diminishes at regular intervals. You can see the difference between the Samsung Galaxy S20 Ultra 5G on the left, which has a medium duty cycle (around 60%), and the Huawei P40 Pro and the Oppo Find X2 Pro, which have long duty cycles (roughly 90%; the black lines show that the OLEDs are turned off, albeit briefly):

So how does DXOMARK measure flicker? One major way is with a device called, appropriately enough, a flickermeter (specifically, a TRD-200 from Westar Display Technologies), whose sole purpose is to measure quick oscillations in brightness. Our engineers follow a strict protocol for measuring flicker on each smartphone display: all devices are individually tested using their default settings under the exact same dark (< 0.1 lux) ambient lighting conditions, and are placed at the same distance from the flickermeter. We chart the output on this graph (which we use to compare up to four phones in our display reviews; note that you can click on the name of a phone in the legend on the bottom of the graph to remove or redraw its results):

Yes, it’s a cool-looking graph, but what does it mean? How should we read this? Well, first of all, keep in mind that these results correlate with each device’s PWM — the on/off power cycle that helps control screen brightness. The horizontal X axis show the frequency of the oscillations over time measured with the flickermeter in hertz (Hz). The vertical Y axis shows the SPD(dB)— spectral power density in decibels, which is the amount of power associated with one frequency of the signal that the display generates.

The first spike in our flicker graph appears at a phone’s listed refresh rate, but it is the highest spike — that is, the one that comes closest to or surpasses 0 dB — that is of interest to us in terms of flicker, as it indicates the PWM frequency; in this case, 241 Hz for the Samsung (S20), 362 Hz for the Huawei, 481 Hz for the OnePlus, and 240 Hz for the other Samsung (Note20). (Just in passing, you can nearly always ignore values below -40 (dB) on the graph, as they correspond to testing noise.)

The very slow-motion video below imitates the results of a flickermeter test. What is interesting to note is that from left to right, the devices scroll faster, which indicates different PWM frequencies.

In this second very slow-motion video, we included the Samsung Galaxy Note20 Ultra 5G that has a refresh rate of 120 Hz; interestingly enough, however, its PWM frequency is 240 Hz (as the flicker graph above also showed). In the video of the Note20 Ultra 5G, you can see that it has one frame on (bright) to five frames off (dark); the P40 Pro ends up with one frame on to three frames off; and the Find X2 Pro varies between one frame on to two or three frames off. All this is to say that where flicker is concerned, even a phone with a fast refresh rate like the Samsung Galaxy Note20 Ultra 5G can have a low PWM frequency and thus noticeable flicker under certain conditions. If you are sensitive to flicker, you will likely notice it on the Samsung devices at this brightness level and these PWM frequencies, but not on other devices with higher PWM frequencies.

Keep in mind that our engineers base their evaluations and the scores they assign to smartphone displays not only on the objective tests they perform with flickermeters and other instruments, but also on perceptual tests that they conduct after being specially trained to see flicker.

To further illustrate flicker, our engineers used a DSLR mounted on a translation rail and moved it quickly while it took a slow (1/10 second) shot of the three mounted smartphone displays shown below to imitate the effects of PWM. In the image of the Samsung Galaxy Note20 Ultra 5G on the left, you can see each individual white dot; on the Huawei P40 Pro in the middle, the individual dots are much closer together, but are still largely discernible; in the image of the OnePlus 8 Pro, however, the dots look more like an almost continuous line. Unsurprisingly, flicker is stronger on the devices where the white dots are further from one another — that is, devices with a lower PWM frequency.

Let’s wrap things up by first repeating that flicker on smartphones is caused by the use of pulse-width modulation that turns light-emitting diodes off and on to control screen brightness levels. As we normally perceive flicker via our peripheral vision rather than via our “attending vision” (that is, what we specifically focus our eyes on), the small size of a smartphone screen makes it less likely that we will see flicker on it (unless we hold the phone very close to our eyes) than we might when viewing content on a laptop screen or monitor. When we do see flicker, however, it’s the PWM that is the culprit; and while flicker can be reduced on a phone with a higher refresh rate, you may sometimes see flicker on it anyway if the phone’s PWM is slow (as we saw with the Samsung Galaxy Note20 Ultra 5G).

Finally, it’s also important to remember that some people are more sensitive to noticing flicker than others; in fact, even people who may not consciously perceive flicker may nonetheless be sensitive to it, winding up with headaches or eyestrain after overdoing their screen time. Such people could choose an OLED smartphone with an anti-flicker feature, or one with an LCD. As you can see in the table below, the last entry shows the data for the Xiaomi Mi 10T Pro; since it uses LCD technology, its PWM frequency is so high that it in essence eliminates the flicker issue.

This all said, you can rest assured that if our testers do discover a smartphone that has noticeable problems with flicker at its default settings, we will let you know about it as part of its Display review. (And by the way, we’ll also mention if a smartphone comes with a “flicker-free” feature or setting.)

I’m using IRIS full version since last December, and do far I can tell the difference from before. Mostly my eyes can tell ? Less eyes strain for sure and more concentration on things I work on. Thank you!

Iris Pro is the full version of Iris that has all the advanced settings and features like more advanced timer settings, brightness, blue light, monitor manager, color schemes, font manager and much more.

I am not sure to understand where is the test. Is it the UFO test with just a line moving, or is it something with that text? Because I do not find anywhere that test with the text…

Now working experience is much better without that flicker but there’s still some weird color blinking being noticed via phone camera… Do you know if that’s ok?

There are some very rare cases, depending on your monitor, that Iris will not remove absolutely all of the flicker, it also depends on the settings of Iris that you have, so it’s possible

After some research I found that it is moire pattern effect caused by something like difference between monitor pixels and particular camera pixel scanning system. Sorry for inaccuracy describing the issue. I do believe that there’s no such effect if you are not filming the screen. Am I correct?

Additionally, the software does not dim my computer when on automatic and health. I think there’s a bug in the software and I am also confused on the above!

My old desktop monitor just died. We need to get another one and set it up with Iris. Can you tell me which monitor you would buy if you had to get a new one? We want to get the best possible one for eyes and then add Iris to make it perfect.

I could not follow at all what you were trying to teach. am I to view all these lines as they appear now on my computer? Are you trying to sell me some program or just help me know how bad or good my computer is for my eyes?

There is, however, a seemingly miss-placed text reading “PWM test” far to the left of the text reading “We will use this to determine if your monitor has PWM flicker….”. I’m guessing the test is meant to show up here?

Where did the GIF versions go? Is it possible to get them back as alternatives to the Youtube video, please? The video display seems to have some problems on my computer, it’s hard to clearly see if it flickers or not. I remember viewing this page earlier when it had the GIF versions, and they were displayed fine.

I agree with TJ and others, about the needless confusion engendered by this piece, and you have failed to address any of those comments. To be precise: this article lacks clarity. In particular, after your text “If your monitor doesn’t use PWM you will see a smooth moving line like this” you have a picture of a thick white bar that blurs into blackness. Which I don’t think represents a moving line at all and is not something that I see. There is no test for the text images displayed either. So why are they even there? Please review.

Completely same.. I am an Engineer and programmer ,and after 10 min. on the page I was suspicious about myself , if I am an idiot not to find a TEST ??.. Good to know I am not alone.. There is no “TEXT TEST” on the page to compare this

Forget about “Testing 123” text , I am just looking for the moving line (first iframe not the yt videos) and again comparing it with the lines in the : https://iristech.co/wp-content/uploads/2018/05/pwm-flicker-types.png

Result : Again None of the patterns , look like my pattern , I see 2 ghost lines moving with my original line with 1,5 -0,8 mm offsets (left and right of the original respectively)..

• Perform highly diversified duties to install and maintain electrical apparatus on production machines and any other facility equipment (Screen Print, Punch Press, Steel Rule Die, Automated Machines, Turret, Laser Cutting Machines, etc.).

• Perform highly diversified duties to install and maintain electrical apparatus on production machines and any other facility equipment (Screen Print, Punch Press, Steel Rule Die, Automated Machines, Turret, Laser Cutting Machines, etc.).

Flicker-free monitors are specially designed to produce a single continuous light source. A typical monitor adjusts its brightness through flickering, introducing periods of low light between higher brightness. While a user may not be aware of the flicker, it can cause a number of issues, including eye strain. However, many monitors now use flicker-free technology to put less strain on monitor users’ eyes.

Look around your typical office and what do you see? Perched on every desk is a computer. Your reliance on computers in the workplace means that office workers are exposed to computer monitors every day, and many of them use the monitor for the majority of their work tasks.

Research shows that the average American worker uses a computer for up to 7 hours a day for work, recreation, or both. Most of us have never realized the degree to which we’re regularly exposed to digital displays. That exposure takes a toll on the health of your eyes, as well as your overall health, over prolonged periods.

Unfortunately, continued exposure to computer monitors can be very harmful to your eyes, causing irritation and discomfort in the short term. It may also lead to more severe issues in the long-term.

Since your screen-centric lifestyles aren’t likely to change anytime soon, it’s vital for us to take proactive preventative measures to maintain the long-term health of your eyes. This includes making modifications to your workstation, as well as practicing healthy eye techniques and strategies.

However, the path to saving your eyes from long-term damage starts with the computer monitor you choose.  Choosing a flicker-free monitor – a display that maintains a steady stream of light – is one of the healthiest choices you can make to protect your eyes.

Before we talk about how the right computer monitor can protect your eyes, we need to first understand how digital displays can potentially degrade your vision over time.

The light emanating from a digital display is different from other kinds of light you’re regularly exposed to, like sunlight or incandescent lights you use when lighting your house.

Most computers on the market today are designed with LED backlighting, which enhances the computer screen’s clarity, brilliance, contrast, definition, and graphics. LED backlighting emits blue light waves that radiate at a brighter intensity than that of natural light or other light waves on the light spectrum. The light from a digital display is composed of what is known as HEV light (high-energy visible light). HEV light occurs in the violet/blue part of the visible spectrum.

Our eyes are not naturally equipped to protect against and filter out intense blue light, meaning that the higher energy of blue light waves can be particularly damaging to your lenses and retinas without taking the correct measures. (For example, switching from a screen to a projector.)

Consistent exposure to harmful blue light rays can cause eye fatigue, dryness, and irritation. It may also lead to digital eye strain or Computer Vision Syndrome, which encompasses a host of accompanying problems and issues, among them headaches, vertigo, and neck pain.

When selecting a computer monitor, you need to be aware of the potential for vision issues caused by blue light waves. Choosing a computer monitor designed to mitigate its harmful effects can be extremely beneficial in maintaining the long-term health of your eyes.

The harmful intensity and energy of blue waves isn’t the only thing you need to think about when selecting a computer monitor. Flicker also presents a genuine danger to the health of your eyes.

Monitors that use LED backlighting flicker through pulse-width modulation (PWM), which enables you to adjust the brightness of your screen easily. If you’re in a sunlit room, you’ll need a bright screen to help you see; when you’re working late at night, you may prefer to dim your screen accordingly.

PWM turns the backlight “on” and “off” quickly at a steady frequency, which decreases the brightness of the screen. This seems like it should be a good thing since you want to be able to fully control the brightness of your screen to adapt to fit your environment and your personal preferences.

The problem is that the computer screen flickers at a very fast rate imperceptible to the human eye as the backlight turns on and off. This flicker causes your pupils to rapidly move from larger to smaller, which in turn causes a multitude of eye issues, including eye strain and eye fatigue.

When you use a non-flicker-free monitor, you are exposing yourself to constant on-screen flickering, which—as we’ve discussed above—can jeopardize the health of your eyes over time. Studies reveal that after only 3 to 4 hours of use of a traditional computer monitor—one that’s not engineered with flicker-free technology – 90% of computer users may experience eye fatigue.

Short-term use of such a monitor may lead you to notice symptoms such as eye fatigue, irritation, eye dryness, short-sightedness, blurry vision, and headaches. Continued exposure could potentially cause irreversible damage to the retinal cells in your eyes.

Computer companies are beginning to address the concerns and dangers that digital displays pose to your eye health. When certain features are integrated into digital displays and computer monitors, your eyes can be successfully protected from digital eye strain.

For example, some companies have attempted to protect your eyes from on-screen flicker but have only created monitors that mask the issue or create the impression of being flicker-free.

Conventional computer monitors flicker at a fixed frequency with comparatively longer periods of time between the “on” and “off” states of the backlight. Consequently, the on-screen flicker of conventional computer monitors is very noticeable.

Some devices attempt to solve the problem of on-screen flicker by integrating PWD as well as high refresh rates. These modifications to the LED backlight actually result in an increase in the frequency of the on-screen flicker and shorten the period between the “on” and “off” states of the backlight.

Since these on-screen flickers are incredibly fast for the human eye to perceive or process, this gives a false impression that flicker has been eliminated. However, it fails to protect your eyes, as they still are forced to rapidly adjust to the “on” and “off” backlight states—only now at a faster rate.

It may seem like we’ve arrived at a catch-22. Non-flicker-free monitors have proven to harm your eyes, and traditional flicker-free monitors still, unfortunately, fail to solve this problem. So what’s the solution?

ViewSonic has used its 30 years of visual solution experience—along with a deep understanding of how traditional computer monitors harm your eyes—to develop a line of computer monitors designed to protect your eye health.

Engineered with flicker-free technology, ViewSonic’s line of monitors is created to reduce flicker and prevent eye strain, eye fatigue, and irritation as well as the development of Computer Vision Syndrome.

Each ViewSonic flicker-free monitor has integrated DC modulation LED backlights, eliminating the “on” and “off” in favor of maintaining a constant stream of light. By removing the “on” and “off” states of the backlight, flicker is completely eliminated at any brightness setting, creating a much healthier viewing experience for the user.

You can easily perform a flicker-free monitor test to determine whether your current computer monitor is flicker-free by using your computer and smartphone.

Start by setting your display to peak brightness. Turn on your mobile phone camera and point it at your computer screen. Now, with your phone’s camera focused on the screen, adjust the brightness to 50% and then eventually down to 0%.  As you lower the screen’s brightness, any flicker will become increasingly noticeable if it’s a non-flicker free monitor.

By conducting this test, you will be able to finally detect on-screen flickers that are usually imperceptible to the human eye. Once you see for yourself how much harmful on-screen flicker you’re exposed to on a daily basis, you’ll be inclined to purchase a more health-conscious computer monitor.

On-screen flicker isn’t the only problem computer users face. Companies have also tried to create monitors that protect your eyes from harsh blue light waves.

ViewSonic has designed a line of computer monitors with blue light filter technology that has been engineered to address this issue. This state-of-the-art technology helps the computer monitor maintain blue light waves that are closer in intensity to realistic, everyday colors.

Make sure your workstation is lit properly – it shouldn’t be too dim or too bright. The goal is to reduce glare and reflection so that you don’t need to strain your eyes and can maintain a healthy viewing experience

When your computer screen uses a cooler color profile, more harmful blue light can emanate. To protect your eyes, adjust the temperature profile to a setting that uses more warm tones and fewer blue ones.

Maintain a proper viewing distance at your workstation. You should not be situated too far or too close; according to the American Optometric Association, a healthy viewing distance means that your screen should be positioned 15 to 20 degrees below eye level, as well as 20 to 28 inches away from the eyes.

To remedy the constant exposure you receive to digital displays in everyday life, it’s critical that you take breaks to give your eyes time to recover, reducing the effects of eye strain. Follow the 20-20-20 rule: every 20 minutes, you should focus your eyes on a point 20 feet away from the computer screen for a total of 20 seconds.

If you find yourself leaning forward to peer at your screen or squinting to make out a word, it’s time toincrease the text size on your device. Your operating system will allow you to make changes to the size of the text you see across all programs, and may even allow you to choose a preferred typeface to aid you in reading.

Screens are everywhere today. If you work in an office, you use one to edit documents and create spreadsheets; if you work in a store or a restaurant, you use a digital point-of-sale system. When you’re off the clock, you use your devices to watch movies, text friends, and shop for clothes. Even when you’re driving, you’re looking at the GPS or passing by digital billboards.

To ensure that your eyes stay healthy, you need to stay aware of the potential dangers of continued exposure to computer monitors. The key is understanding how certain computer monitors can impact the health of your eyes, either positively or negatively.

Start by taking the flicker-free monitor test to find out what level of flicker you’re exposed to on a regular basis. If your test shows that your monitor performs poorly, or if you’re experiencing eye fatigue or other issues like headaches or neck pain, it may be time to consider a new monitor.

The next step is to configure your workstation as needed. When setting up your monitor, be sure to take into account ergonomics recommendations with regard to viewing distance and viewing angle.

For more information, visit ViewSonic to learn more about our innovative visual solution technologies, how to maintain an ergonomically sound workstation, and other healthy eye practices.

Screen flickering in Windows 11 is usually caused by a display driver issue or incompatible app. To determine whether a display driver or app is causing the problem, check to see if Task Manager flickers. Then, based on that information, you"ll need to update, rollback, or uninstall your display driver or update or uninstall the app.

If Task Manager flickers along with everything else on the screen, a display driver is probably causing the problem. In this scenario, see the Fix your display driver section.

If Task Manager doesn"t flicker while the rest of the screen is flickering, an incompatible app is probably causing the problem. In this scenario, see the Update or uninstall an incompatible app section.

If Windows Update recently made updates to your device, roll back your display driver. Otherwise, try updating or uninstalling your display driver to fix the flickering or scrambling problem.

After you uninstall the first app, restart your device and check if the screen flickering or scrambled issue is resolved or not. If it"s not, uninstall each app one by one until the issue is resolved.

Screen flickering in Windows is usually caused by display drivers. To update your display driver, you"ll need to start your PC in safe mode, uninstall your current display adapter, and then check for driver updates.

Expand the Display adapters section, select and hold (or right-click) the listed adapter, then select Uninstall device. Select Attempt to remove the driver for this device, then select Uninstalland restart your PC.

I"ve recently got an LCD monitor and it is occasionally "flickering" colors very noticeably. It"s not a new monitor, but the person I"m borrowing it from hasn"t had any trouble with it.

Computer monitors have come a long way from the bulky, heavy CRTs to the sleek, modern LCDs of today. One of the most significants improvements in display technology as of late is the LED backlight, which results in a brighter, sharper picture while reducing the power consumption. Manufacturers tout the benefits of LEDs over the older CCFL (fluorescent) backlights. However, some people experience issues like unusual eye strain, pain, or headaches which seem to be caused by their new monitor. And the most likely culprit is the LED backlight flicker.

"But wait," you might say, "I thought LCD displays were supposed to be flicker-free!". Indeed, while CRT monitors redraw the whole screen many times a second (determined by their refresh rate), LCD monitors provide a constant image, simply changing the pixel colors from one to another. The speed of this process depends on the monitor"s response time, which is different from refresh rate. So, the source of flicker in modern liquid crystal displays isn"t the LCD matrix itself, but rather the backlight.

In LED monitors, this flickering occurs when the brightness is reduced from 100% due to a backlight dimming method called PWM (Pulse-Width Modulation). In many cases, when a laptop is running on battery power, PWM will kick in even at maximum brightness to save energy. CCFL monitors also use PWM, but the resulting flicker might actually be less noticeable than with LEDs - more about that below.

Pulse-width modulation, or PWM, is a technique that is used for dimming LCD backlights, among other things. It involves cycling the backlight on and off faster than the human eye can see. PWM dimming kicks in as soon as you reduce the brightness setting on your monitor from its maximum value. It has many advantages over analog dimming, which provides continuous lighting: PWM is cheaper to implement, offers a wider range of adjustment, and prevents color shifting at lower brightness settings.

So if PWM-dimmed LEDs are so great, can they really cause problems like extra eye strain or headaches? Humans cannot see the LCD backlight flicker with a naked eye, after all. Certainly, provided a sufficiently high PWM switching frequency is used - such as 500 Hz - even the most sensitive people shouldn"t be affected. However, it seems that many LCD monitors currently on the market use backlight frequencies between 100 Hz and 200 Hz. Humans still can"t perceive the backlight cycling on and off at that frequency, but it doesn"t mean that this LED PWM flicker won"t hurt their eyes or affect their nervous system. Consider the following information:According to studies about 1 in 4,000 people are highly susceptible to flashing lights cycling in the 3 to 70 Hz range [...] Less well known is the fact that long-term exposure to higher frequency flickering (in the 70 to 160 Hz range) can also cause malaise, headaches, and visual impairment.

There is good evidence that fluctuations in the light signal are detected by the nervous system up to perhaps 200 Hz.http://grouper.ieee.org/groups/1789/public.html

Physiological evidence in humans and monkeys shows that flicker rates above the perceptual critical flicker frequency threshold can nevertheless generate cortical and subcortical visual responses.Martinez-Conde, S., Macknik, S.L., and Hubel, D.H. (2002). Proc Natl Acad Sci, USA 99, 13920-13925.

Different points in the visual system have very different critical flicker fusion rate (CFF) sensitivities. Each cell type integrates signals differently. [...] some retinal ganglion cells can maintain firing rates up to 250 Hz.http://www.bio.net/bionet/mm/neur-sci/2007-July/061925.html

This video shows the the LED backlight of a MacBook Pro flickering 40 times slower, so you can actually see what"s happening when you dim the brightness on your LCD screen. This video was taken with high speed camera by TFTcentral.co.uk crew.

You might wonder why people who nev