lcd display issues free sample

This article is part of the LCD Motion Artifacts 101 series. This page illustrates overdrive artifacts (inverse ghosting) of different response time acceleration settings on a computer monitor. Different manufacturers uses different terminology. ASUS uses “Trace Free” for their computer monitors, while BENQ uses “AMA“, and Acer uses “Overdrive“.

Another method of reducing the visiblity of ghosting and coronas is to use a faster LCD display (e.g. 120Hz, 144Hz, or 240Hz monitor) and/or to use an LCD display with a strobe backlight such as ULMB or LightBoost (see Motion Blur Reduction FAQ) which hides pixel transitions by turning off the backlight between refreshes, as well as reducing motion blur (60Hz vs 120Hz vs ULMB). Ghosting and coronas are the visible pixel transitions being seen by the human eye.

Without overdrive, LCD displays are prone to ghosting. Ghosting is typically caused by the asymmetric speeds of pixel transitions. LCD pixels often transition faster (or more completely) to a specific color, than back from a specific color. This creates the differences in motion artifacts on the leading edge versus the trailing edge of moving on-screen objects.

The use of overdrive can also reduce motion blur very slightly, but only up to the limitations of the sample-and-hold effect. See www.testufo.com/eyetracking for an animation that demonstrates display motion blur unrelated to speed of pixel transitions.

A stationary camera is good for photographing pixel transitions statically. However, it is not a very accurate representation of perceived display motion blur and motion artifacts:

Pursuit camera are used by display manufacturers for testing (e.g. MPRT pursuit cameras). This is simply a camera that follows on-screen motion. These expensive cameras are extremely accurate at measuring motion blur and other artifacts, since they simulate the eye tracking motion of moving eyes.

LCD motion artifacts are frequently caused by pixel response imperfections. For more information about pixel response, see GtG versus MPRT: Frequently Asked Questions About Pixel Response.

Troubleshooting CRTs versus LCDs begins with similar steps, but diverges due to the differing natures of the two display types. The first troubleshooting steps are similar for either display type: power down the system and display and then power them back up; make sure the power cable is connected and that the outlet has power; verify that the signal cable is connected firmly to both video adapter and display and that there are no bent pins; verify that the video adapter is configured properly for the display; try the problem display on a known-good system, or try a known-good display on the problem system; and so on. Once you"ve tried the "obvious" troubleshooting steps, if the problem persists, the next step you take depends on the type of display. The following sections cover basic troubleshooting for CRTs and LCDs.

CRTs seldom fail outright without obvious signs, such as a loud snap or a strong odor of burning electrical components. Most CRT problems are really problems with the power, video adapter, cable, or hardware/software settings. To eliminate the CRT as a possible cause, connect the suspect CRT to a known-good system, or connect a known-good display to the suspect system. It is worth noting, that older CRTs eventually wear out, and starts dimming. Common signs of a weak CRT are a dim picture, dysfunctional brightness and/or color controls, image smearing at high brightness, and in color CRTs, a tint towards a single color (Red Green Blue)

CRTs contain multiple filaments, which can be broken, or gas may have leaked into the vacuum inside the CRT. CRTs damaged this way are unrepairable without specialist equipment. With the display open. check if all three filaments are glowing bright orange. Excessive redness or purple arcing signifies gas has leaked in. There may also be an internal short inside the CRT, which is also unfixable without specialist equipment.

If you have ACPI or APM power management enabled, it may be causing the problem. Some systems simply refuse to wake up once power management puts them to sleep. We have seen such systems survive a hardware reset without restoring power to the CRT. To verify this problem, turn off power to the system and CRT and then turn them back on. If the CRT then displays an image, check the power management settings in your BIOS and operating system and disable them if necessary.

The horizontal and/or vertical deflection system has failed. The CRT tube itself is fine, but the circuitry driving the tube has failed. Replace the display.

There are two likely causes. First, you may be driving the CRT beyond its design limits. Some CRTs display a usable image at resolutions and/or refresh rates higher than they are designed to use, but under such abuse the expected life of the CRT is shortened dramatically, perhaps to minutes. To correct this problem, change video settings to values that are within the CRT"s design specifications. Second, the power receptacle may be supplying voltage lower than the CRT requires. To correct this problem, connect the CRT to a different circuit or to a UPS or power conditioner that supplies standard voltage regardless of input voltage.

The video card settings are likely outside the range supported by the CRT, particularly if you have just installed the CRT or have just changed video settings. To verify this, restart the system in Safe Mode (press F8 during boot to display the Windows boot menu and choose Safe Mode). If the system displays a VGA image properly, change your display settings to something supported by the CRT.

Most modern CRTs can display signals at many different scan frequencies, but this doesn"t mean that the CRT will necessarily automatically display different signals full-screen and properly aligned. Use the CRT controls to adjust the size and alignment of the image.

The CRT may need to be degaussed. A CRT that sits in one position for months or years can be affected even by the earth"s very weak magnetic field, causing distortion and other display problems. Exposing a CRT to a strong magnetic field, such as unshielded speakers, can cause more extreme image problems. Many modern CRTs degauss themselves automatically each time you cycle the power, but some have a manual degauss button that you must remember to use. If your CRT has a manual degauss button, use it every month or two. The degaussing circuitry in some CRTs has limited power. We have seen CRTs that were accidentally exposed to strong magnetic fields, resulting in a badly distorted image. Built-in degaussing did little or nothing. In that case, you can sometimes fix the problem by using a separate degaussing coil, available at RadioShack and similar stores for a few dollars. We have, however, seen CRTs that were so badly "magnet burned" that even a standalone degaussing coil could not completely eliminate the problem. The moral is to keep magnets away from your CRT, including those in speakers that are not video-shielded.

An incorrect yoke may have been attached to the CRT. Unless you have a lot of spare time on your hands, this is usually not worth fixing. Replace the display.

If your LCD displays no image at all and you are certain that it is receiving power and video signal, first adjust the brightness and contrast settings to higher values. If that doesn"t work, turn off the system and LCD, disconnect the LCD signal cable from the computer, and turn on the LCD by itself. It should display some sort of initialization screen, if only perhaps a "No video signal" message. If nothing lights up and no message is displayed, contact technical support for your LCD manufacturer. If your LCD supports multiple inputs, you may need to press a button to cycle through the inputs and set it to the correct one.

Unlike CRTs, where increasing the refresh rate always reduces flicker, LCDs have an optimal refresh rate that may be lower than the highest refresh rate supported. For example, a 17" LCD operating in analog mode may support 60 Hz and 75 Hz refresh. Although it sounds counterintuitive to anyone whose experience has been with CRTs, reducing the refresh rate from 75 Hz to 60 Hz may improve image stability. Check the manual to determine the optimum refresh rate for your LCD, and set your video adapter to use that rate.

First, try setting the optimal refresh rate as described above. If that doesn"t solve the problem and you are using an analog interface, there are several possible causes, most of which are due to poor synchronization between the video adapter clock and the display clock, or to phase problems. If your LCD has an auto-adjust, auto-setup, or auto-synchronize option, try using that first. If not, try adjusting the phase and/or clock settings manually until you have a usable image. If you are using an extension or longer than standard video cable, try connecting the standard video cable that was supplied with the display. Long analog video cables exacerbate sync problems. Also, if you are using a KVM switch, particularly a manual model, try instead connecting the LCD directly to the video adapter. Many LCDs are difficult or impossible to synchronize if you use a KVM switch. If you are unable to achieve proper synchronization, try connecting the LCD to a different computer. If you are unable to achieve synchronization on the second computer, the LCD may be defective. Finally, note that some models of video adapter simply don"t function well with some models of LCD.

If the screen is displaying a full, stable image, but that image is of poor quality, first verify that the display is not connected through a KVM switch or using an extension cable. If so, connect the display directly to the video adapter using the standard cable. If that is already the case, adjust the brightness, contrast, and focus controls. If you are unable to get a proper image using these controls, the problem is most likely a clock or phase mismatch, which you can cure by taking the steps described in the preceding item.

Your video card is supplying a video signal at a bandwidth that is above or below the ability of your LCD to display. Reset your video parameters to be within the range supported by the LCD. If necessary, temporarily connect a different display or start Windows in Safe Mode and choose standard VGA in order to change video settings.

This occurs when you run an LCD at other than its native resolution. For example, if you have a 19" LCD with native 1280x1024 resolution but have your display adapter set to 1024x768, your LCD attempts to display those 1024x768 pixels at full screen size, which physically corresponds to 1280x1024 pixels. The pixel extrapolation needed to fill the screen with the smaller image results in artifacts such as blocky or poorly rendered text, jaggy lines, and so on. Either set your video adapter to display the native resolution of the LCD, or set your LCD to display the lower-resolution image without stretching the display (a feature sometimes referred to as display expansion), so that pixels are displayed 1:1, which results in the lower resolution using less than the entire screen.

This is a characteristic of LCDs, particularly older and inexpensive models, caused by defective pixels. Manufacturers set a threshold number below which they consider a display acceptable. That number varies with the manufacturer, the model, and the size of the display, but is typically in the range of 5 to 10 pixels. (Better LCDs nowadays usually have zero dead pixels.) Nothing can be done to fix defective pixels. Manufacturers will not replace LCDs under warranty unless the number of defective pixels exceeds the threshold number.

Some people claim that leaving the unit powered off for a day or two will "erase" a persistent after-image. Others suggest leaving a neutral gray screen (like the one used for phase adjustment) up on the screen to "equalize" the display. I dunno. FWIW, I"ve seen this problem on older Samsung panels but never on the Sony or NEC/LaCie panels I use.

Again, this is a characteristic of LCDs, particularly older and inexpensive models. The after-image occurs when the display has had the same image in one place for a long time. The after-image may persist even after you turn the display off.

Transistor-based pixels in an LCD respond more slowly than the phosphors in a CRT. The least-expensive LCDs exhibit this problem even with slow image movement, as when you drag a window. Better LCDs handle moderately fast image movement without ghosting, but exhibit the problem on fast-motion video. The best LCDs handle even fast-motion video and 3D gaming very well. The only solution to this problem is to upgrade to an LCD with faster response time.

Use the brightness control to increase image brightness. If you have set brightness to maximum and the image is still too dim, contact the display manufacturer. The CCRTs used to backlight the screen have a finite lifetime and may begin to dim as they near the end of their life.

If one or more horizontal and/or vertical lines appear on the display, first power-reset the computer and display. If the lines persist, run the auto-setup function of your display. If that does not solve the problem, power the system and display down, remove the video cable, and verify that the video plugs and jacks on both computer and display ends do not have broken or bent pins. Even if all appears correct, try a different video cable. If the problem persists, contact the display manufacturer.

Unfortunately, most of that stuff requires either a certified repair or a complete replacement to fix. Unless you’re especially handy with electronics and you just happen to have access to cheap replacement parts, it’s usually better to either return a monitor to the manufacturer (if it’s under warranty) or simply buy a new one. Even so, here are the most common ailments for modern LCD monitors, and what can be done to fix them…or not.

An incorrect refresh rate setting can also cause flickering. The refresh rate is the number of times the computer sends an image to the monitor per second, expressed in hertz. Most LCD monitors use either 59 or 60 hertz, though 75Hz, 120Hz, and 144Hz are also found on premium monitors. Go into your operating system’s display settings (right-click desktop and head to Display settings > Display adapter properties > Monitor in Windows 10) to make sure the right hertz setting is applied—you may need to update your video drivers as well.

Black or single-colored lines on LCD screens are caused by a lot of different issues, but if the standard fixes outlined in the flickering section above don’t fix them (check your video and power cables for problems, install new drivers), it’s probably a physical defect in the screen itself. Try your monitor on another computer or laptop to see if the problem persists; if it does, you’re probably looking at a replacement, since the error is almost certainly in the LCD panel (the most expensive component of the monitor).

A “dead” pixel is a single dot on your LCD screen that doesn’t illuminate, showing up as one or more black squares. “Stuck” pixels are similar, but instead of showing black they’re stuck on a single color that doesn’t match the computer screen’s image, typically either red, green, or blue.

If your monitor has a visible crack, a large discolored area, or a black/multicolored spot that doesn’t align with the pixel grid, it’s been subjected to physical trauma and the LCD panel is damaged. There’s nothing you can do here: even if your monitor is within its warranty period, it almost certainly won’t cover physical damage. You could try to replace the LCD panel itself, but since the replacement part will be almost as expensive as a new monitor anyway, you might as well start shopping.

If the problem persists even when you’re testing the monitor on another machine, there might be something wrong with the internal electronics. Try an alternative input (HDMI/DisplayPort/DVI) if possible.

Most of the above problems can happen to the LCD screens used in laptop PCs and tablets, too…but because of the compact build, they’re much harder to repair. That being said, the extra expense of a laptop versus a monitor might make it a much better candidate for a repair rather than a replacement. At the very least (assuming you’re out of the warranty period), it’s probably worth a diagnosis and quote at a repair shop, if you’re not comfortable replacing the screen assembly yourself.

Many Apple products use liquid crystal displays (LCD). LCD technology uses rows and columns of addressable points (pixels) that render text and images on the screen. Each pixel has three separate subpixels—red, green and blue—that allow an image to render in full color. Each subpixel has a corresponding transistor responsible for turning that subpixel on and off.

Depending on the display size, there can be thousands or millions of subpixels on the LCD panel. For example, the LCD panel used in the iMac (Retina 5K, 27-inch, 2019) has a display resolution of 5120 x 2880, which means there are over 14.7 million pixels. Each pixel is made up of a red, a green, and a blue subpixel, resulting in over 44 million individual picture elements on the 27-inch display. Occasionally, a transistor may not work perfectly, which results in the affected subpixel remaining off (dark) or on (bright). With the millions of subpixels on a display, it is possible to have a low number of such transistors on an LCD. In some cases a small piece of dust or other foreign material may appear to be a pixel anomaly. Apple strives to use the highest quality LCD panels in its products, however pixel anomalies can occur in a small percentage of panels.

In many cases pixel anomalies are caused by a piece of foreign material that is trapped somewhere in the display or on the front surface of the glass panel. Foreign material is typically irregular in shape and is usually most noticeable when viewed against a white background. Foreign material that is on the front surface of the glass panel can be easily removed using a lint free cloth. Foreign material that is trapped within the screen must be removed by an Apple Authorized Service Provider or Apple Retail Store.

If you are concerned about pixel anomalies on your display, take your Apple product in for closer examination at an Apple Store, Apple Authorized Service Provider, or an Independent Repair Provider. There may be a charge for the evaluation. Genuine Apple parts are also available for out-of-warranty repairs through Self Service Repair.*

If our video displays aren’t operating properly, then it will be very difficult to get anything done on our computer. In this video, you’ll learn how to troubleshoot video image issues, burn-in problems, pixel problems, artifact issues, and more.

We wouldn’t be asking if it wasn’t something that would actually solve the issue. However, if that doesn’t resolve the issue, we can move to more complex troubleshooting tasks, like checking the input for the monitor. Many monitors have different types of input. You might have an input for VGA, for HDMI for DisplayPort, and other interfaces as well. And if that input is set incorrectly, you’ll get a black screen, so check to make sure exactly which interface the computer is plugged into in the monitor, and make sure your input settings match that interface.

If the monitor is suddenly working, we can focus our troubleshooting efforts on the computer. If you get the normal startup messages from your BIOS and the Windows’ splash screen, but then everything goes black after that, the problem maybe related to Windows. This can sometimes occur if there are issues with the video driver, or issues with the monitor description file. In order to bypass both of those, you can press F8 during the startup process, and use VGA mode to use a basic mode configuration that nearly any monitor will be able to display.

Sometimes our display issues are complaints about the quality of the image. You may have flickering or color patterns that are not correct in the image. And this may make the entire use of the computer less than optimal.

You’ll want to check settings, such as the refresh rate and the resolution of your operating system settings, and compare those to what the native resolution is of the monitor. For the best possible display, you’ll want these settings to match the native resolution and settings for the monitor that you’re using. And if the image happens to be flickering on and off, you may want to also try replacing the cable and see if that resolve some of those issues.

Another configuration setting that could affect the visual display is hardware acceleration. This is often an option within the graphics card configuration settings, or within the driver itself. If you’re seeing odd patterns on the screen, you might want to try disabling hardware acceleration, and see if that resolves the issue.

As we mentioned earlier, the native resolution of an LCD display should match the resolution configuration in your operating system. If you set that resolution too low in your operating system, all of the icons and information on your screen will appear very, very large. So you may want to change those resolution settings to make everything appear a bit more normal on the screen.

Another problem you often see on many different kinds of monitors is burn-in. When an image is constantly displayed on a screen, you’ll find that that screen will lock that image in place. And even when that image is not being displayed anymore, we can still see at least part of that image still on the display.

Here’s an example of some burn-in, or ghosting, that you might see on a display that’s from an airport. This is showing all of the available flights you can see there are flight numbers and gates and times. And it shows if the flight is on time, or what the scheduled time might be. You can see that this on-time marker used to be a little further to the right, because you can see this discoloration on the screen. And you can clearly read, on time, where this image has been burned into this display.

Many modern displays will recognize when an image has been displayed on a screen for an extended period of time. And if that occurs, it will begin to move the image one pixel or two in a different direction to try to make sure that the image is moving around and not burning in any part of that screen. Certain LCD displays might even have a pixel that is stuck to a particular color that may have been left on for an extended period of time. If that occurs, you can sometimes remove that from the screen by displaying a white screen over an extended period.

If a display has a particular pixel that is always showing a color, we call that a stuck pixel, where it is constantly bright. Even if the entire screen is black, you will still see that brightly lit pixel on the screen. You have also pixels that aren’t working at all. We call these dead pixels, because they will never show any particular color. They will always be black on the screen.

If you have a stuck pixel or a dead pixel, this is usually related to a problem with the display itself. And to be able to resolve that, you would need to replace the LCD display.

Another problem you might find is image persistence, where you might close a window on the screen, and yet part of that window is still being displayed. That information should be refreshed, so usually changing the configuration of your graphics card or resetting the monitor might resolve that issue.

When your system starts, there are a number of processes that occur to load the operating system. In this video, you’ll learn about the steps of the boot process and the tools available to help troubleshoot any issues.

And if you’re still not sure why this monitor is not displaying anything, you may want to try swapping it out with a known good monitor to see if the problem follows the monitor, or if it stays with the computer that you’re using.

It may be that the monitor is working properly. In fact, you can see some images on the screen. But maybe you’re having problems with the image. Perhaps it’s flickering or the colors don’t look quite right. In this case, it’s almost usable, but it’s obviously a bit irritating to use and you do want to find out why you’re having these video issues.

If the image on the display itself is distorted or fuzzy, you may want to look at your operating system and makes sure that the settings inside of your OS match the capabilities of the monitor that you’re connecting to. Check the refresh rate in the resolution settings.

If at all possible, you want to be able to match the native resolution of the LCD display to have the best possible image. If your operating system and the monitor are matching up, you may also want to try checking or replacing the cable, especially if it’s an analog connection.

If you’ve ever worked with a laptop that did not have the proper video driver loaded, one of the things you’ll notice are that the images and the icons look really large on the screen. That’s because the resolution isn’t set properly. So you need to make sure that you match the native resolution of your LCD with the settings in your operating system.

And one problem that exists across all different kinds of monitors– CRTs, LCDs, plasma, and others– is a burn-in issue. This is when you have something on the screen that’s there constantly, and eventually that image becomes permanent on the display. Some displays have a function that will shift the pixels after a certain amount of time to avoid any of these burn-in issues.

LCDs also have this problem with images sticking on the screen for extended periods. You may want to try displaying a completely white screen on your LCD to try to get that image to fade away from being permanently displayed.

Sometimes your problem with the display is at the pixel level. You may run into stuck pixels, which are pixels that are always going to display a color. Even if everything else on the screen is a black screen, you may see one pixel that’s lit. That is a stuck pixel.

And you might also run into dead pixels. Dead pixels are always black. They never display a color. Even if your entire screen was white, you’d be able to very easily pick out where those dead pixels are.

If you are having a problem with image persistence, especially burn-in on your screen, make sure that you power your screen off for extended periods of time. And if you see motion trails, it may be that some of the advanced video features of your adapter card are causing a ghosting or an image display as you’re moving things around the screen.

Yes, it happens. It was 2013 when I had a phone call from BenQ, a multinational manufacturer of LCD monitors. The project manager mentioned that one kind of LCD TV screen they were currently shipping damage. BenQ team looked for a solution from us to prevent broken TV monitors when shipped because defective products are not what any good business would want to do.

It was BenQ’s biggest embarrassment. They had a factory in mainland China and every time certain models of LCD screens were produced, they would be shipped to PChome Taiwan for sale. However, the recent damage rate of the goods had been abnormally high up to nearly 20%. Taking preventive measures, such as adjustment of packaging materials or structure, etc., there is no significant effect.

The situation became increasingly serious and it’s not just that it was BenQ who noticed this problem; customers’ feedback also showed that their LCD TVs were suffering from abnormal damages when delivered to them. Without any big accidents happening during the transportation or delivery process at all – one could only imagine what was going on inside those.

We had conducted a study on what type of shock can affect the LCD screen and how much damage it entails. We first put types of indicators labels in the box of the LCD panel in order to determine how much force damage would occur during regular shipment and transit.

In fact, change the handling environment is the fastest and most effective way to solve damaged LCD TV screens, and where Impact Label comes to play! BenQ is not the first user of impact indicators in LCD TV manufacturers. To comply with your LCD TV, our free consultant and free samples for testing are waiting for you.

Have you ever left your TV or monitor on for days, stuck on the same image? You return to your screen, only to find an image burned into the display. No matter what you do, it won"t go away. It is a permanent image burn.

Why do monitors and TVs get image burn? Why can"t manufacturers prevent LCDs and plasma screens from a burnt image imprint? Moreover, what can you do to fix an image burn?

Before flat-screens and crystal displays, most TVs and monitors featured CRT (Cathode Ray Tube) technology. In CRTs, individual pixels comprise a red, blue, and green phosphor component. Depending on the intensity of each phosphor component, the pixel appears to the human eye as a unique color.

Plasma displays use plasma, a gaseous substance containing free-flowing ions. When the plasma is not in use, the particles in the plasma are uncharged and display nothing. With the introduction of an electric current, the ions become charged and begin colliding, releasing photons of light.

LCD and LED do not work in the same way as CRTs, either. LCD and LED screens use backlit liquid crystals to display colors. Although manufacturers market screens using LED and LCD, an LED screen is still a type of LCD. The white backlight filters through the liquid crystals, which extract particular colors per pixel.

LCD and LED displays don"t suffer from the same type of image burn as CRTs and plasma screens. They"re not completely clear, though. LCD and LED screens suffer from image persistence. Read on to find out more about image persistence.

Before you can fix screen burn-in, take a second to understand why these images burn in the first place. LCDs and LEDs don"t suffer from burn-in as seriously as plasma screens. But static images can leave an imprint on both display types if left alone for too long. So, why does image burn happen?

LCD and LED screens can also experience image burn, though the image burn process can take longer to develop into a permanent issue. In addition, LCD and LED screens suffer from another issue, known as image retention (also known as image persistence or an LCD shadow).

Image retention is a temporary issue that you are more likely to notice before it becomes a permanent issue. However, proper image burn can still affect LCD, LED, and OLED screens.

The other thing to consider is that LED and OLED image burn-in, when it happens, is irreversible. That"s because of how LED and OLED screens work. Individual pixels within an LED display decay when they emit light.

Issues arise when a screen shows a single news channel 24 hours a day, every day, causing channel logos to burn-in, along with the outline of the scrolling news ticker and so on. News channels are a well-known source of television burn-in, no matter the screen type.

Image burn-in fixes exist for LCD and plasma screens. How effective an image burn-in fix is depends on the screen damage. Depending on the length and severity of the image burn, some displays may have permanent damage.

My personal rule of thumb is to turn off the display if I plan on being away for more than 15 minutes. That way, it is difficult to get caught out, plus you save yourself money on electricity costs and monitor or TV wear and tear.

If your plasma or LCD screen already has image burn-in, you can try turning on white static for 12 to 24 hours. The constant moving of white-and-black across your screen in random patterns can help remove the ghost image from your screen.

Pixel-shift constantly slightly adjusts the image on your screen, which varies the pixel usage to counteract image burn. You might have to enable a pixel or screen shift option in your screen settings. Pixel-shift is a handy feature for LED and OLED screens that cannot recover from image burn and should help counteract an LCD shadow.

Other modern screens feature built-in screen refresh functions that the manufacturer will advise using to remove image retention and image burn issues.

While the Deluxe version uses advanced algorithms to repair burned screens and prolong plasma and LCD longevity, the official site is no longer up and running, and there is no way to download the full version officially.

When it is playing video content such as a DVD, the operating system has to synchronize playback with the display redraw rate. The video frame is updated during the vertical blanking interval so that the complete, correct frame will be displayed without any tearing every time that the video card refreshes the monitor.

When windows synchronizes DVD playback with the monitor refresh rate, it synchronizes with the timing of the primary monitor. This is determined by the video driver. Some video hardware supports multiple monitors but does not synchronize the display redraw timing of the two monitors. Even though the two monitors are configured for the same refresh rate (for example, 60 Hz), the second monitor may not be refreshed at the same time. In this case, there may be unavoidable tearing on the second monitor.Resolution

If the computer system meets the hardware and software requirements to run Windows Aero, you may be able to reduce or eliminate the problem by enabling Aero. Otherwise, set the display to PC Only or Extended. For more information about Aero, go to the following Microsoft website:

If your computer does not meet the requirements for Aero, set the display to PC Only or Extended. For information about how to change this setting, go to the following Microsoft website:

If you experience noticeable cut lines or tearing, and not only when you play a DVD movie, the display may be configured to a refresh rate that one of your monitors does not support. If this is the case, you can resolve the issue by configuring the display to a refresh rate that is supported by all monitors.

During the assembly process, the use of a liquid optically clear adhesive (LOCA) is important for ideal visual properties in LCD screen manufacture. The assembly process has evolved and advanced, but there are still potential weaknesses or defects that must be taken into account in both adhesive selection and process design. In this blog installment, we will discuss one of these potential defects: entrapped bubbles.

However, if the digitizer or LCD is also damaged during a fall, that screen no longer carries value because it cannot be refurbished. Repair shops cannot sell broken LCDs to refurbishing companies; therefore, they cannot offset the cost of an LCD repair. That is why repair stores often charge a little extra if there is damage to the LCD or digitizer, to make up for that loss. Repair stores that don’t have an additional charge for an LCD repair typically inflate their glass repair price to make up for the loss from damaged LCDs. If they have one price, that means everyone is paying more to cover the cost of customers who have damaged LCDs and customers who only have cracked glass. This is why TCR separates the price of glass and LCD repairs for you! If you only have cracked glass, you only have to worry about paying to replace the cracked glass.

If your phone or tablet’s glass is shattered there will be cracks or chips on the screen itself. If it is just the glass that is damaged, the device may still function and you may be able to use it normally. If this is the case, it is likely that only the glass needs to be replaced. To prevent further damage to your device it is best to get it repaired quickly. For example, if liquids seep through the cracks it could cause permanent damage to the LCD.

Many people may continue to use their touchscreen with shattered glass and delay fixing the glass on their devices; however, if the touchscreen isn’t responsive, it could be a sign of more significant damage to the device’s digitizer which is integrated with the LCD screen.

A pixelated screen can indicate LCD damage. This would look like a patch of multicolored dots, a line or lines of discoloration, or a screen with rainbow colors. For many people, these colors are an easy way to know that their LCD is broken and that they should get it repaired.

Dropping your phone isn’t the only reason you’ll end up with a pixelated screen. Over time, your screen’s LCD may break down through regular use. This happens to other devices aside from your smartphone or tablet. Pixelation can happen to TVs and computers, too. People typically decide to buy a new device when this happens. Fortunately, with an LCD repair, you can fix the device without needing to replace it.

A black screen or black spots on your smartphone or tablet is an indication of a damaged LCD. Often with a bad LCD, a phone may still turn on and make noises, but there is no clear picture. This does not necessarily mean any other part of the phone is damaged and a simple screen replacement will get it functioning again. Sometimes it can mean a battery or other internal component is damaged. It is best to have a highly qualified phone repair technician diagnose what is wrong so the appropriate repair can be made.

Fortunately, your mobile device is fixable whether you cracked the glass or damaged the LCD. Stop by or call TCR: Triangle Cellular Repair at (919) 263-2699 for a free diagnostic and quick, affordable cell phone repair in Chapel Hill and surrounding areas. We’re always happy to help!

Accidental Damage is any damage due to an unintentional act that is not the direct result of a manufacturing defect or failure. Accidental damage is not covered under the standard warranty of the product. Such damage is often the result of a drop or an impact on the LCD screen or any other part of the product which may render the device non-functional. Such types of damage are only covered under an Accidental Damage service offering which is an optional add-on to the basic warranty of the product. Accidental Damage must not be confused with an occasional dead or stuck pixel on the LCD panel. For more information about dead or stuck pixels, see the Dell Display Pixel Guidelines.

The LCD glass on the display is manufactured to rigorous specifications and standards and will not typically crack or break on its own under normal use. In general, cracked, or broken glass is considered accidental damage and is not covered under the standard warranty.

Spots typically occur due to an external force hitting the screen causing damage to the LCD panel"s backlight assembly. While the top layer did not crack or break, the underlying area was compressed and damaged causing this effect.

If your Dell laptop LCD panel has any accidental damage but the laptop is not covered by the Accidental Damage service offering, contact Dell Technical Support for repair options.

TFT LCD image retention we also call it "Burn-in". In CRT displays, this caused the phosphorus to be worn and the patterns to be burnt in to the display. But the term "burn in" is a bit misleading in LCD screen. There is no actual burning or heat involved. When you meet TFT LCD burn in problem, how do you solve it?

Burn in is a noticeable discoloration of ghosting of a previous image on a display. It is caused by the continuons drive of certain pixels more than other pixels. Do you know how does burn in happen?

When driving the TFT LCD display pixels Continously, the slightly unbalanced AC will attract free ions to the pixels internal surface. Those ions act like an addition DC with the AC driving voltage.

For normal white TFT LCD, white area presenting minimal drive, black area presenting maximum drive. Free ions inside the TFT may are attracted towards the black area (maximum drive area)

When the display content changed to full screen of 128(50%) gray color, all the area are driving at the same level. Those ions are free again after a short 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.

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.

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.

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.

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.

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!

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.

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.

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.)

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.

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).