Defective pixels. How many dead pixels are allowed? Number of permissible dead pixels depending on the monitor class
If you want to exchange an already purchased monitor with dead pixels, keep in mind that there is international standard ISO 13406-2 regulating the permissible quantity defective pixels on the LCD monitor. Thus, the seller may refuse to exchange your monitor or return your money if the number defective pixels V .
1Acceptable number of defective pixels on the monitor
The permissible number of defective pixels depends on the display class (pixel fault class). The ISO 13406-2 standard distinguishes four classes: first does not allow the presence of defective pixels. As a rule, everything is modern LCD monitors relate to second grade. Below you can calculate the acceptable number of defective pixels according to the ISO 13406-2 standard for monitors second class:
|
Note. In the calculation, the fractional number of defective pixels is rounded to a whole number by discarding the fractional part.
The ISO 13406-2 standard identifies the following defects: always-on white pixels (type I), always-off black pixels (type II), subpixel defects (type III), which appear as colored pixels always on/off in primary colors (red, green). , blue, cyan, magenta, yellow).
In addition, for resolutions of 1 million and higher, accumulation of color defective pixels (type III) is allowed nearby in a 5 x 5 pixel square. This defect is called a cluster. Second class monitors does not allow the presence of 5 x 5 clusters with defective pixels of type I or II. For more details see.
In practice this a large number of Defective pixels as specified in ISO 13406-2 are extremely rare. The wide tolerance can be explained by the fact that the standard was developed in 2000. Since then, LCD panel manufacturing technologies have undergone improvements.
2How to check your monitor for dead pixels
Examination LCD monitor on presence of defective pixels consists of carefully examining the screen to identify abnormal pixels. The inspection is carried out sequentially for the primary colors: black, white, red, green, blue, cyan, magenta and yellow.
Stuck or dead
Have you ever noticed a static pixel (small dot) on your LCD screen? If so, then you have a stuck pixel. Luckily, stuck pixels don't always stay stuck. As for dead pixels, these are hardware problems. They are often caused by manufacturing defects - pixels should not get stuck or burn out over time.
A stuck pixel is different from dead pixels in that it is more often one color - red, green or blue - all the time, while a dead pixel is often only black.
Usually a dead pixel is very rare; more often it is the consequence of the fact that you did not restore the stuck pixel in time. Subpixels within a pixel accumulate excess energy over time and burn out.
Many people come across the white pixel and confuse it with a bit/dead pixel, however this pixel is known as a “hot pixel.” all subpixels in it are active and it is always stuck.
Do you have defective pixels? Yes, it's hard to say. The easiest way to notice this is by setting your screen to a background with a single fill. We have made this procedure easier by adding a test to Bad Crystal.
Of course, a speck on your screen could be a piece of dirt or dust - run your finger over it (gently!) to make sure. if it doesn't move, then it's more likely a defective pixel
So you've found a defective pixel - what now?
Try BadCrystal if you're looking for a program that does this. Bad Crystal is a unique utility to clean your screen from stuck pixels, smudges and vertical stripes. The innovative algorithm and high technologies used in Bad Crystal make it possible to restore up to 90.7% of all defects on LCD screens in a few minutes.
Yes, but this is a hardware problem - how software will this fix it?
There are programs that quickly change colors, thereby affecting subpixels. If a matrix with rapidly changing colors is located in the area of a stuck pixel, the program constantly polls the stuck pixel for a color change, thereby supplying it with extra energy that contributes to its recovery.
It doesn't work, what should I do?
Chances are you either hit the 10% or the pixel that you are trying to fix is dead =(
Try the method of massaging the defective area. Again, be careful - don't press too hard or use anything sharp, you could easily damage your monitor.
Manufacturer's warranty
Unfortunately, one faulty pixel cannot be a reason to exchange the device under warranty - even if you just recently purchased the computer. Various manufacturers have different policies for dealing with stuck or dead pixels. Some manufacturers will replace a monitor that has at least one bad pixel, while most manufacturers require an N-minimum number of bad pixels before offering warranty service.
Documentation
Learn all about stuck pixels. What is a stuck pixel? How are they formed? and much more...
How to check a monitor or TV for dead pixels, glare and other defects? There are a huge number of different methods for these purposes, and we will look at some of them in this article. But, friends, in such a delicate matter as checking the screen, what is more important is not the specific method of checking, not the tools used, but a clear understanding of what possible defects we are looking for. And we will also talk about this below. So, you are going to buy a monitor or TV. How to check it before buying it in a store or before accepting it postal parcel, if this is an online order?
Tools
To check the quality and integrity of a monitor or TV screen, there are a lot of different Windows programs and web services. Among the first:
- Utility included in the AIDA64 program,
- Nokia Monitor Test,
- EIZO Monitortest,
- Monitors Matter CheckScreen,
- PassMark MonitorTest etc.
There are narrow-profile utilities only for checking for search dead pixels, For example:
- Dead Pixel Tester and
- Pestretsov Dead Pixel Test.
From web services offering services for various tests for the quality and integrity of screens:
- Monteon.Ru,
- Tft.Vanity.Dk etc.
Each of these programs, each service, of course, has its own advantages, but I, friends, will tell you that you don’t need any particularly ornate tools to check your monitor or TV. Some of the tests included in such tools are needed not for verification, but for image adjustment. To check the screen for quality and integrity, you can use simple means at hand.
If we, for example, are looking only for dead pixels, in Windows environment 10 do this:
Go to the “Personalization” section of the “Settings” application;
In the “Background” subsection, set “Solid color”, click “Additional color”;
Choose a white, light gray or red shade on the color scale. Click “Finish”;
We go down to the last subsection and hide the Windows taskbar;
Finally, we remove the display of shortcuts on the desktop in context menu the last one.
We do the same in others Windows versions taking into account differences in personalization settings.
In this simple way we can check the monitor for dead pixels, glare and color rendering quality. If you need to check for glare, then, accordingly, as background picture choose black color. We evaluate the behavior of problematic pixels when transmitting other colors, as well as the quality of color rendering in general, by alternately changing the color of the desktop background. We use blue, green, yellow, red, cyan and violet.
Regarding other nuances of the screen - smooth transition between colors, sharpness, correct geometry, absence of blurred boundaries, absence of trails during frame dynamics, etc. – You can check your monitor or TV using a video on YouTube. We go to the video hosting site and enter the query “monitor test” into the search engine. In the search results, we bypass all sorts of reviews and guides, and only run video tests directly.
We expand the video to full screen. Where you need to look closely, press the spacebar to pause and then continue playing the video.
Video tests on YouTube are often recorded screencasts of screen tests performed using the same specialized programs and web services. But, friends, another advantage of video hosting is that with its help you can check the quality of the screen on “live” pictures. Those. the same way we would use a monitor or TV in everyday life. For example, Samsung has a special video to present all the beauties of the company’s products, which perfectly demonstrates the quality of color rendering and the reproduction of dynamic scenes by the screens.
How effectively does the monitor display video footage? high resolution, we can see with the help of artistic videos on search queries"4K" or "8K".
Foreign inspection territory
The above screen testing methods are applicable when we have a Windows device or the Internet. These conditions will not be in the mail. It’s also not a fact that an electronics store will allow us to install some of their programs or surf the Internet on their test computer. You can only rely on the reproduction of a universal content format. If you need to check a monitor or TV on foreign territory, a flash drive will help. You can transfer test images and videos to it. Almost everything modern televisions and some functional monitors include built-in USB media players. Only if we buy a monitor with basic functionality will we have to ask the supermarket to arrange a connection to some image source. In the case of mail, of course, there is nothing left to do but drag your device and cable there.
- Note: friends, please read this first. full specifications purchased monitor. If the model provides support for MHL technology, video and audio output from mobile devices via the HDMI or MicroUSB port, you can check the quality of the screen when accepting a package at the post office using your smartphone. To do this, of course, you need an appropriate connection cable, as well as an application or media content for testing screens. The same goes for wireless connection technologies.
Where can I get media content to check my monitor or TV and put it on a flash drive? Pictures and videos need to be downloaded from the Internet. For example, I found a special selection of pictures with images for testing screens on Rutreker.
Well, now friends, let's get to the point. What screen defects should you look for? And how to look for them?
Correct color rendering
Color accuracy is a check of primary colors and shades to see how correctly the screen displays them. It can be checked using pictures like this.
Such images can also be used when setting up a monitor or TV - testing ready-made presets, adjusting brightness/contrast settings manually.
Smoothness of transitions (gradients)
Gradients - transitions of color shades - should be displayed smoothly, without sudden changes, without steps. Checked with pictures like this one.
You can also view gradient fills for each of the primary colors, for example, like this picture for the green spectrum.
Banding
Banding is vertical or horizontal stripes with a distinct shade of color.
Whether this defect is present is checked using pictures with a solid fill. Such pictures with primary colors (white, gray, black, yellow, blue, green, red, purple) must be part of the test content.
Tint
Tint is chaotic areas of incorrect display of white, usually with pinkish or greenish tints. To find this defect, we use an image with a solid white fill.
Geometric proportions
Images with grids of different sizes will help determine how correctly the geometric proportions of the screen are displayed.
Trail during dynamic video sequence
Test animation with fast moving objects will allow you to determine whether trails - traces from objects - remain on the screen during dynamic playback of the video sequence.
Defective pixels
When searching for dead pixels, we use a single-color image of white, light gray or red. Broken or dead pixels can be detected immediately; these are dark dots on the screen. So-called stuck pixels can glow as dots of white, red, green, purple, yellow or other colors. Stuck pixels, accordingly, will be visible when a contrasting single-color image is presented on the screen.
To detect any kind of pixel defects, you need to examine the screen up close. You can use a magnifying glass. If the TV or monitor is under warranty, it needs to be checked additionally to look for defective pixels, but after purchase, when it has worked for a couple of hours. Problem pixels may not appear immediately, only when the matrix is heated.
Highlights
Highlights are the light areas on dark background along the edges of the screen.
PLS matrices usually do not suffer from the problem of screen glare; MVA matrices do have them, but rarely. But, unfortunately, this problem is inherent in IPS matrices and old TN ones. When purchasing an IPS or TN monitor, especially a model in the budget segment, you must check the purchase for the presence of glare. To do this, you need to present a monochromatic black image on the screen and turn up the brightness to the maximum. It is advisable to carry out the test itself in a darkened room.
Here, friends, are the main problems of monitors and TVs that need to be checked before purchasing. If you have anything to add on the topic, write in the comments.
The user consumes information through a monitor or laptop screen, so the presence of defects on it is unacceptable. The monitor itself is a fairly simple device, but at the same time quite fragile. The main trouble that a user may encounter when purchasing a monitor is the presence of dead pixels, that is, screen elements that are not capable of correctly transmitting colors. To avoid such a problem, you need to carefully check it when purchasing a monitor, and in this article we will look at how to do this.
Table of contents:What is a pixel, what are dead pixels?
First we need to tell you a little theory. A pixel is the smallest part of the display that displays an image. Depending on the display resolution and its diagonal, a pixel may be larger or smaller in terms of physical size.
Please note: Modern monitors can use several million pixels.
If one pixel or group of pixels is not working, the image on that part of the screen will not match the one sent to the monitor from system unit. There are several types of dead pixels:
- Non-working. These pixels do not convey the image, and they are always black;
- Stuck pixels. Most often these are pixels that are stuck in blue, red or green. They are not capable of working with RGB colors;
- Constantly glowing pixels. These are pixels that are constantly lit in white.
Please note: Sometimes not just one pixel fails, but a group of pixels in a horizontal or vertical stripe, or “squares” of pixels, for example, 5 by 5 or 10 by 10 elements, are damaged.
Why is it important to check your monitor for dead pixels when purchasing?
When purchasing a new monitor or laptop, be sure to immediately check for dead pixels in the store. This is due to the fact that if you discover such a defect after purchase, it is far from certain that you can return the monitor under warranty. The fact is that there is a standard ISO13406-2, which determines the permissible number of defective pixels for monitors of various classes.
This standard provides for the release to the market of monitors in 4 quality classes. The best class is first, the worst is fourth.
Please note: Almost all mass-produced monitors are produced according to the second quality class, respectively, according to the standardISO13406-2 implies the presence of dead pixels.
According to standard ISO13406-2, the following number of non-functioning or malfunctioning pixels in monitors of various classes per one million pixels in the panel is allowed:
- 1st quality class. There should be no defective pixels at all;
- Quality class 2. No more than 2 permanently lit white pixels, 2 permanently off black pixels, 5 pixels with other defects are allowed;
- Quality class 3. No more than 5 permanently lit white pixels, 15 permanently non-lit black pixels, 50 pixels with other defects are allowed;
- Quality class 4. No more than 50 permanently lit white pixels, 150 permanently non-lit black pixels, and 500 pixels with other defects are allowed.
It is worth noting that the acceptable value of defective pixels does not mean that they are necessarily present on a monitor of one class or another. The quality class of a monitor according to accepted standards is determined by the device manufacturer itself. Depending on what class it determines, additional warranty obligations are imposed on it.
How to check your monitor for dead pixels
When purchasing equipment in a store, you always have the opportunity to check it right on the spot, and in a situation with a monitor, this definitely needs to be done. Exist special applications, which allow you to check your monitor for defective pixels. Programs are available, both standalone and presented on various sites.
The principle of operation of all programs for checking the screen for dead pixels is identical. The entire working area of the display is filled with a single color, a group of colors or a gradient, which allows you to see dead pixels if they are present on the monitor. Let's look at the main programs and sites that can be used for such a check.
Programs for checking your monitor for dead pixels
If you buy a monitor in a store, it is better to first record one of the programs described above on a flash drive in order to perform an on-site test.
Dead Pixel Tester
One of the most famous free applications to check your monitor for dead pixels. To use Dead Pixel Tester you need to:
Among the program’s capabilities, it should be noted that the function of changing modes can be set to a timer; to do this, you need to check the “Auto Color Cycle” box and set the time in milliseconds. After this, the modes will change automatically.
Another feature of the program is the creation of a limited area on the screen with constantly changing colors. To create it, you need to click on the “Exerciser” button, after which the corresponding square area will be created. It can be dragged with the left mouse button. If there is any doubt that there is a dead pixel in some part of the monitor, this tool helps to verify this.
IsMyLcdOk
IsMyLcdOk is another application that does a good job of diagnosing dead monitor pixels. The program also does not require installation and can be easily downloaded for free on the Internet. The application weighs very little and works extremely simply.
When you first launch the IsMyLcdOk program, information will appear that describes what you should click to perform the test. To return to the instructions after starting the diagnostics, you will need to press F1.
To test, select the mode using the buttonsF2-F5. Among the monitor test modes available in the IsMyLcdOk program:
- Check BitBlt MB/sec;
- Painted rectangles;
- Painted stripes;
- Durability testing;
- Vertical lines;
- Horizontal lines.
In addition to special modes, it is also possible to simply switch colors or gradients.
Sites for checking your monitor for dead pixels
If you don’t want to download a program to your computer to check your monitor, you can use sites with similar functionality. Let's consider a couple of options.
Please note: Sites for checking the screen for dead pixels are convenient to use, for example, when testing tablets or smartphones.
Monteon
A simple and functional service for testing your monitor for dead pixels.
To use the service you must:
To finish testing the monitor with the service, click on the house icon in the lower left corner of the screen.
Please note: ServiceMonteon, unlike the programs discussed above, has a mode in which looped video is shown. IN this mode You can check the pixel color refresh rate.
Vanity Monitor Test
Quite an old, but well-proven service that allows you to test your monitor. For work of this service will need to be on your computer Adobe Flash Player, which can be considered its disadvantage. To start testing, you need to click “HTML Windows”.
The choice of operating mode in the Vanity Monitor Test program is carried out through the drop-down menu at the top.
Treatment of dead monitor pixels
Dead pixels on the screen are not always a death sentence. In some cases it is possible to get rid of them and make them function again standard mode. There are several ways to do this:
If none of the above methods did not help restore the dead pixel, you will have to put up with it, or replace the monitor.
Although liquid crystal panels have long ceased to be a dream, even when using the most modern technologies, there are defects that can greatly spoil the mood of a perfect purchase. In order to be completely satisfied with the purchased product, you need to check the TV for dead pixels when purchasing.
Today, liquid crystal displays are not something unusual or extraordinary. On the contrary, in addition to televisions, they are present in many devices: computer monitors, phones, cameras, navigators and other similar equipment. The basis of LCD or LCD technology is liquid crystals. After light from lamps or LEDs passes through a layer of crystals, a corresponding picture appears on the screen.
The matrix of a color TV is a huge number of tiny indivisible rectangular or round cells called pixels. In turn, each such object consists of red, green and blue subpixels. It is these colors, or rather their combinations, that are considered the basis of color television. The simultaneous lighting of all pixels forms a complete image on the screen. Moreover, the more pixels, the clearer the picture. If you look closely at the display, you can easily see the three colored areas of these objects.
The concept of dead pixels, the reasons for their appearance
The number of pixels on the display is so huge that it is almost impossible to guarantee their 100% serviceability. Often on the screen you can see dots glowing in one color, completely motionless, which even with a change in the TV image do not change color or location. It is these objects that are commonly called dead pixels. They can be black, white and colored. There are two reasons for the occurrence of these defects: imperfect technology and ordinary manufacturing defects.
Dead pixels occur in two layers: liquid crystals and thin-film transistors.
After the transistor that controls the liquid crystals fails, black (“dead”) dots appear, indicating non-functioning cells. Subsequent management of these crystals is simply impossible. Such defects are most visible on a light background. Some experts consider it impossible to “treat” them, others argue that using a laser it is possible to partially return the pixel to its working condition.
The second reason is the subpixel frozen in one position. This problem appears in the liquid crystal layer. Such a “stuck” object appears on the display as a white (burning) or colored dot. To eliminate this defect, you can use special programs or carry out a series of physical manipulations. There are cases when dead pixels, after some time, disappear on their own.
Thus, when choosing an LCD TV, it is not enough to pay attention to its appearance, the presence of numerous functions, ports, connectors. It is also important to check the device for matrix defects. Let's try to figure out how to check a TV before buying and protect yourself from purchasing low-quality equipment.
Allowable number of dead pixels
You can often see a picture in stores when a buyer tries to return a newly purchased TV after discovering defects on the screen, in particular, dead pixels. For the sake of truth, we note that usually a dispute between a store and a buyer ends not in favor of the latter. To avoid getting into an unpleasant situation, we recommend choosing a TV very responsibly. In particular, it is worth knowing how to point of sale check the LCD TV when purchasing for dead pixels, get acquainted with certain standards, according to which displays are divided into four classes.
How to check a TV in a retail chain
The information in the table indicates that first class products are completely free of dead pixels. The cost of a product depends on its class.
The picture is formed on the screen by all pixels of the display. For example, Full HD resolution (1920 x 1080) involves more than two million pixels. Knowing the acceptable standards for dead pixels and methods of checking for such defects, it is not difficult to choose high-quality equipment.
Device testing can also be done using special programs by connecting the TV to a computer or laptop. Often the buyer does not have a computer at hand, so it is extremely difficult to carry out such manipulations in the store. Many stores now offer paid service to check screens for defects. What to do in this case, should you agree or should you still try to cope with this work on your own?
The simplest way is visual inspection screen at close range to the presence of a dot glowing in a different color. An ordinary magnifying glass will be a reliable assistant in this check. Detection of black dots is possible when a white field is applied to the screen. To find white spots, just make the screen dark. Finding defective color subpixels can be made easier by changing the screen color one by one.
It is important to remember that some defects do not appear immediately, but only after the matrix is heated. Pictures in the form of colored stripes, grids, and checkerboard fills will also help you quickly find malfunctioning subpixels that stand out from the general background.
If you are planning to purchase new equipment, first of all, study the relevant information, in particular, how to check the TV when purchasing it in a store. To carry out testing, you need to select special images and videos. They contain special pictures of different colors that appear alternately on the screen. Then write this information onto a flash drive, and then go get the TV. Videos are usually accompanied by music, which allows you to simultaneously check the quality of the acoustics.
Many today prefer new generation devices with Ultra HD resolution (3840 x 2160). They are characterized by excellent color saturation, perfect transition from one shade to another, the ability to adapt any format to 4K, excellent sound, and many additional functions. To check a 4k TV when purchasing, you need to use pictures with the appropriate resolution.
Is it possible to “cure” dead pixels?
Often, defects on the display appear during operation. Black dots, as mentioned earlier, cannot be removed on your own. As for colored pixels, there are two ways to get rid of them: physical treatment and hardware massage.
The first method involves using a regular cotton swab to massage the damaged area where the “stuck” pixel is located. Such manipulations are carried out in a circular motion with the device turned off. This method cannot be called completely safe, because careless movement not only will not save you, on the contrary, it may add to trouble.
The second method is to use special programs that are easy to find on the Internet. BadCrystal – does not always cope with the task, however, it’s worth a try. Practice shows that it removes stuck spots within a few minutes or a couple of days. The JScreenFix program is no less popular today. She not only finds the defect, but also eliminates it. Operating time from 20 minutes to 10 hours.
Thus, armed with the necessary test kit, you can safely head to the store for a new TV. Rush when checking the device is unacceptable. The test should be completed slowly, examining each section of the screen step by step.
