my lcd screen is flickering manufacturer

The reason for LCD Display flashing screen: shielding coil; Signal interference; Hardware; Refresh frequency setting; Monitor time is too long; Too high frequency; Similar to the frequency of the light source.

LCD display, divided into CCFL backlight and LED backlight two. When the display uses CCFL backlight (that is, usually said LCD display), backlight power off, the lamp will continue to emit light for about a few milliseconds; When the display is backlit with an LED (commonly referred to as an LED backlight display), the characteristics of the LED light allow it to control the speed of switching on and off the power supply more quickly, so there will be no continuous lighting when the power is off. Therefore, the LED backlight flashing screen will be more obvious than the CCFL backlight.

LCD is easily disturbed by a strong electric field or magnetic field, and sometimes the screen jitter is caused by the magnetic field or electric field near the LCD. To liquid crystal display ruled out clean everything around interference, the computer can be moved to an empty table, surrounded by then boot test, if the screen dithering phenomenon disappears, it means that your computer where you found it has a strong electric field or magnetic field interference, please send suspiciously (e.g., speakers of the subwoofer, power transformers, magnetizing cup, etc.) from a computer nearby.

Turn off the LCD and turn it back on a few times to degaussing. (today’s monitors have automatic degaussing when turned on.) LCD screen flashing reason: LCD screen refresh rate problem & display and video card hardware problems display.

In fact, the main reason for the LCD screen dither is the LCD refresh frequency set lower than 75Hz caused by, at this time the screen often appear dither, flicker phenomenon, we only need to put the refresh rate to 75Hz above, then the phenomenon of the screen dither will not appear.

Sometimes because the use of liquid crystal display time is too long, there will be a jitter phenomenon. In order to test whether the electronic components inside the display are old or not, the faulty display can be connected to someone else’s computer for testing. If the fault still disappears, the display is broken and needs to be repaired.

The frequency of the LCD display screen itself is too high, which leads to screen flashing. Generally, there are a few problems in real life that cause screen flashing due to high frequency. People’s naked eyes have no flicker feeling for the picture over 60hz, while the design standard of the general LCD display screen is basically maintained on this data, so the frequency will not be too high under normal circumstances, but at the same time, the screen itself can not be ruled out fault. After the relevant instrument measurement is indeed the fault of the screen itself, in addition to the replacement of a new monochrome LCD screen is the design of equipment-related software.

LCD display and light source frequency close to the situation of the splash screen is very common, because the frequency of the different light source is different, in certain cases, the frequency of the LCD display screen and artificial light similar flicker is also more common, the best way at this time is a kind of artificial light or LCD display equipment, avoid the splash screen.

LCD display, although the price is not high, there are various problems. It will have various effects on our work and life. In ordinary life, when using LCD, as long as pay attention to the following points, will extend the life of LCD.

• 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.).

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.

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.

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.

Is your phone"s screen behaving oddly? Have you noticed your iPhone or Android phone"s display glitching? It could be doing so for several reasons. From loose internal connections to buggy software, many issues can cause a smartphone screen to flicker.

The first thing to do when trying to fix a glitching phone screen is to restart your phone to ensure that this isn"t a temporary issue. Performing a restart kills any active third-party background services and processes that could be causing the display problem.

Restarting will also refresh your phone"s memory components if any of them crashed during a task. After rebooting, if the display is no longer flickering or glitching, you should review all the recent apps you"ve installed. If the problem comes back, try the next tip on this list.

Rebooting is the most basic troubleshooting step you can execute, and it does the trick for most problems. However, if it doesn"t fix your flickering display, consider wiping your phone entirely by performing a hard reset. Doing so will restore your phone to its factory settings and clear the cache.

If there"s any unprocessed data hampering your phone"s functions, a hard reset will clear everything right away. However, before performing a factory reset, don"t forget to back up your Android phone or your iPhone. Note that backing up a Samsung phone is slightly different since you need a Microsoft account to do so.

If your Android screen is still flickering, try switching to Safe Mode for a couple of hours. Safe Mode lets you use your phone without third-party apps and services. Unlike a factory reset, Safe Mode retains your phone"s data, and you can return to the regular experience anytime you want.

However, note that Safe Mode is merely a diagnostic tool and won"t solve the problem. If your phone works fine in Safe Mode, it means the problem is caused by a third-party app, not your phone.

The auto-brightness (Adaptive brightness) setting is responsible for constantly altering the screen"s illumination based on light sensor data. But a software update or hardware defect could lead to unexpected snags, including display flickers. Therefore, another straightforward action you can take is to disable the option from the Settings menu.

When rendering graphics, your phone dynamically decides whether the CPU or the GPU will handle the job. While the transition is usually seamless, a damaged or aged phone can struggle with screen compositing (layering images).

There is a minor delay between tasks when the phone doesn"t have anything to display. Hence, the flickering. But disabling hardware overlays can help. To do so, you"ll first need to enable Developer options.

Once in developer mode, head back to your phone settings and scroll to the bottom until you find Developer options. In it, scroll down to find Disable HW overlays and toggle it on. Note that this will consume extra power since disabling overlays forces the phone to use GPU rendering.

It"s possible that the display problem you"re facing might have spawned from a messy software build. Usually, a simple software update fixes the issue, so check if there"s an update available for your device. To check your software version on Android, go to Settings > System > System update. For iOS, go to Settings > General > Software Update.

You can also consider checking in with the manufacturer for updates or scour forums for a temporary solution. We don"t recommend this, but you can also try downgrading to an older Android version to see if it fixes the issue.

Unfortunately, there"s no guarantee that any of these steps will work. Sometimes, a glitching phone screen is due to a hardware failure, and there may be significant costs involved for repair or replacement. That"s why it"s worth giving each one of these tricks a shot first.

That said, your last resort is to get in touch with your device"s manufacturer and have your phone screen checked out by a professional. If none of these techniques worked, you might be facing a more complex issue. In these scenarios, the only option is to send your phone in for repair or replacement.

Since your phone plays such an active role in your life, you need everything to work correctly. Smartphones house many delicate and interconnected components, and the malfunctioning of any one can cause flickering displays.

Don"t worry; a flickering phone screen is usually fixable, assuming it"s a software issue. Even though mobile phones are complex and can be daunting to repair, trying these at-home tricks first can save you a lot of money versus buying a brand-new device.

Flickering and dimming are some of the common problems affecting flat-screen TVs today. You may have a highly acclaimed TV but can still experience some of these problems from time to time. Your TV may flicker due to a bad video input, a non-optimal lighting condition, or a connection problem. And, if you’re experiencing this while connecting a video player, you might want to learn how to connect a VCR to a TV.

So why is my TV flickering? Well, when your TV screen flickers, it’s often a fluctuation in the picture quality that either leads to dark or bright frames intermittently without displaying any content on the screen. And if you are a gamer that has been dealing with lag, you may want to check out our guide on reducing input lag on the TV.

When this happens, it’s normal to feel it could be an issue that requires technical repair. However, it is essential to note that a TV screen flicker might be caused by things other than internal hardware issues.

TVs that exhibit flickering can do so for a variety of reasons, both internal and external. In most cases, the user can fix the issues with basic troubleshooting. We also have great guides for other simple fixes. For pixelation problems, you can read our guide, so you never have to ask why is my TV pixelating again. Or if you are questioning, why does my TV keep turning off? We have you covered as well.

Defective or loose cables plugged into your unit can cause screen flickering. For example, on an HDMI cable, the result appears as flickering colors or “snow.” It is random, with abrupt color intensity and brightness on coaxial and other types of analog cables. Getting a replacement cable will fix this problem. Additionally, if you are seeing a black and white screen and it’s not supposed to be, a loose cable could cause this as well. For more ways to troubleshoot this, read about why your TV is black and white. This can also be the cause if you keep asking yourselfwhy your TV keeps buffering.

Faulty electrical appliances in your household could draw power affecting your TV, and cause flickering. If you turn on an appliance in your home, and your TV abruptly flickers before getting back to normal when the appliance’s power cycle is complete. The flickering, in that case, is caused by electrical interference.

To resolve this problem, have your primary household ground checked by a qualified technician at the service panel. Make sure there is a tight connection. If possible, have a dedicated power output to service the appliance or your TV to prevent the interruption causing the flicker.

Accumulated dust can harm your TV’s electrical arcing. However, this will only affect CRTs and large-chassis rear-projection units. The best remedy for this problem is good maintenance which means keeping a clean environment.

TVs are designed with a power supply circuitry that will maintain a proper voltage level to keep a picture at a stable level of brightness. If the power supply begins to fail, you will notice a marked abrupt brightness level change and dimming. The TV unit might also project a black screen. This is a sign of hardware damage that will require professional repair and service. Additionally, if you hear a pooing noise come from your TV the power supply, could be one of the reasons. You can read about why your TV makes a popping noise for more information and to troubleshoot the problem.

TVs like LEDs work by backlighting the projected image with a set of LED lights. If one or more LED bulbs malfunction, the user will begin to notice flickering spots. Unfortunately, there’s no simple way to fix this, and depending on the model, you’ll require LED replacement service and repair or a new TV unit altogether. If you require a new TV, check out our Samsung Q90R review or one of our many other reviews to help your search.

Smart TVs require regular over-the-air updates. In some cases, your TV screen might flicker due to outdated firmware. Updating the TV’s software or firmware with new updates and switching it off and on will solve the issue. While you are in the settings of your TV, you can check to see if your TV is HDR, if you are curious. You may also want to find out why your digital TV channels keep disappearing as software issues may be a cause too.

TVs that exhibit flickering can do so for various reasons, both internal and external, including; loose cables, faulty electricals, low power supply, dying bulbs, and outdated firmware or software.

STAT:The current global Cable TV share is under 50%. There are 1,775 TV stations and over 5,000 cable systems operated by 660 institutions, reaching an estimated 90% of the entire U.S (source)

Often, these TVs have capacitors that go bad. I have fixed many. You problem could be a PSU issue and specifically capacitors. You must pull the back off to see this. Other than that it is a guessing game without more visual clues unless it totally dies. Then it may be easier to find the problem.

Bad capacitors will be the usually black cylindrical ones on PCBs. There may be many of different diameters and lengths. Primarily you are looking for the larger ones to start with. The tops have an X mark on top and the top is flat to slightly concave. If the top is at all convex it is between going bad and totally bad. It may also be leaking around the bottom.

Dell has received reports from portable system users and users of some desktop LCD displays on how the LCD display would randomly dim/brighten or occasionally flicker for no apparent reason.

Ambient Light Sensors are devices that detect the amount of available light in the workspace and automatically dim or brighten the LCD display based on the amount of light the system is encountering. Most newer automobiles have similar technology to brighten or dim the dashboard lights. Generally, complaints about ambient light sensors on LCDs can be traced to the light source intensity changing rapidly and the LCD attempting to cope with the changes (Partly cloudy days, curtains blowing in a breeze even a failing flourescent lamp).

If a system is being used on battery power, and the LCD is too dim, then the brightness may be adjusted with the Fn Key keystrokes for your system. Portable LCDs are set to full brightness on AC power by default, and to less than 1/2 that on battery to save power. On battery the ALS is normally disabled.

You may need to disable the Ambient Light Sensor if you cannot control changing light situations (Working outdoors etc.) On most portable systems, this function is controlled in the BIOS (ALS enabled/Disabled.)

On desktop LCD equipped with ALS, the on screen display controls allow you to enable to disable the sensor. Often the ALS cannot be seen on the display bezel on a desktop LCD. In the image below you can see the ALS next to the camera in the LCD bezel of a Latitude E6410. (See Figure 1)

The on screen display (OSD) options for a ALS equipped desktop LCD display (Dell G2210 for example) may look something like the photo below. (See Figure 3)

Whether your laptop screen flickers occasionally or continuously, it"s not only a distraction but it could mean that a hardware problem has developed. Troubleshooting the exact cause of a flickering screen can be challenging, but the cause may be something as minor as a loose cable.

Inverter Board The inverter board provides the laptop"s backlight lamp power. It does this by converting AC current to DC. If the inverter board is shorting out or failing, it could cause your laptop screen to flicker.

Backlight Lamp The backlight lamp provides light to the LCD or LED laptop screen. LCD laptop screens generally use CCFL backlights, while LED screens use LED backlights. Your laptop"s screen may flicker if the backlight lamp is failing or if the power cable from the inverter board is not securely connected.

Loose Cables Your laptop screen can flicker if the connection between components is not secure. The easiest way to test for loose cables is to slowly open and shut the laptop screen while looking to see if this causes more or less flickering. If you are able to position the screen at an angle at which it stops flickering, this is a good indicator that your laptop may have a loose cable connection.

Replace or Repair Once you"ve determined whether your laptop has a faulty inverter or backlight, or a loose cable, you can replace the part or repair the connection. Manufacturers typically advise that you should bring the laptop to a repair shop for service, but if you are confident that you can do it yourself, visit the manufacturer"s website for documentation detailing the procedure.

Most laptop screens have LCD or LED displays that although may function correctly most of the time can have issues that can cause flickering. There are a lot of different reasons why the screen on your laptop may flicker. Perhaps it is hardware issues such as the connections on the screen but it can also be software issues. Whatever the cause, this problem is fairly common which means that it is easily fixed.

In this article, we take a look at some of the reasons why your laptop"s screen flickers and also provide you with some of the most effective solutions to this problem.

Some third-party apps have been known to cause a computer screen to flicker on Windows 10. These include Norton AV, iCloud, and IDT Audio. If you have one of these apps or other third-party apps that you think maybe incompatible with the system, it may be a good idea to update them.

Updating your display drivers may also be able to help you fix this flickering issue once and for all. But to safely do this, you need to boot the computer in Safe Mode, uninstall the current display adapter, and then check for driver updates. Here"s a step by step guide to do that;

You can also change the refresh rate of your monitor. The refresh rate refers to how many times the screen redraws each second. This setting may be related to older desktop monitors, but it may also affect the quality of LCDs in Laptops as well. To modify the screen"s refresh rate, follow these simple steps;

Data loss is another problem that many laptop users face. Like this flickering issue, data loss can also be caused by several issues including accidental deletion, malware and viruses, and even hardware and software issues. Therefore when you lose data on your laptop, you need a solution that will make the process of data recovery very easy, while ensuring a very high recovery rate. This tool is

The program will immediately begin scanning the selected location for any missing file. Keep in mind that this scan can take a while depending on the amount of data on the drive and the individual size of the files.

You can also double click on the file to bring up a popup preview window. When you are certain this is the file you need, click on "Recover" to save the file to your computer.

This laptop screen flickering issue is a problem that can occur at any time. The solutions above should be able to help you fix the issue once and for all. Let us know in the comments section below if the solutions worked for you. As always questions and comments on this and any other issue are also welcome.

If your laptop flickers when moved, you need to update your graphic card drivers. Go to the "Hardware and Sound" section of your Control Panel. Select the "Display Adapters" and choose the tab "Device Manager". This is where you will see the model and brand of your video card so that you can update it on the manufacturer"s website.

You can stop your laptop screen from flickering by disabling Windows Desktop Manager. Create alignment between the refresh rates of your external monitor and your laptop. Go to the manufacturer"s website and get the latest drivers to download.

Make an update of your graphics driver or video card to resolve this issue. You can also adjust the display settings of your computer to achieve the best resolution for your monitor. Log on with Safe Mode or perform a clean boot of your system.

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.)