Allowed number of dead pixels. How many dead pixels are allowed? Checking your monitor for defective pixels
Defective pixels
In matrix devices consisting of large quantity identical cells In computer displays, for example, it is not uncommon to encounter image defects that appear on only one cell or a small group of cells. The most common defects:
Damaged pixel of the LCD monitor of a Nikon Coolpix 3100 camera, magnification about 20x
"Defective pixels"(also “dead” or “bad” pixels, the official name is defective pixels, English defective pixels) - defect electronic device, perceiving or reproducing an image and having a pixel structure. Manifests itself in the constancy of the output signal (brightness in the case of a monitor, data in digital file in the case of ) several pixels.
"Hot pixels"(English) hot pixels) - a defect in which the value of the output signal has an incorrect dependence on the input, or the output signal is most dependent on other factors (temperature, the value of neighboring pixels).
"Dependent pixels"- a slang term meaning the dependence of a particular pixel on the value of its surroundings. Typically not noticeable in realistic images. Can only be detected on the monitor by a “checkerboard” fill or “grid”.
The reason for the appearance of such a defect is a malfunction of the matrix element, in the case of a “dead pixel” - a constant malfunction. Since manufacturing a matrix is an expensive and time-consuming process, and it can be checked for malfunctions only after complete production, manufacturers try to reject products as rarely as possible, classifying them according to test results into one of the quality classes.
For electronic storage devices ( random access memory, flash memory) the term “bad cell”, “bad cell”, “bad block” is traditionally used, since, unlike photographic and display devices, there is no obvious connection with the location of the defect in the image.
“Dead pixels” on photographic matrices
In the case of a matrix of a digital camera, video camera, scanner, document camera or other image-perceiving device, the output signal value is the numerical value of the corresponding pixel in the digital camera file. The vast majority of digital cameras provide masking " dead pixels» by interpolating their values from neighboring ones (thus turning them into “dependent”).
By most manufacturers, the presence of no more than 3 (some - 5) dead pixels is not considered a matrix defect.
The presence of a “line” of hot pixels, as well as groups of closely spaced hot pixels, is considered a matrix defect.
“Dead pixels” on monitors
The ISO 13406-2 standard establishes 4 quality classes for monitors based on the permissible number of dead pixels. Monitor sellers also set a certain threshold for their product, usually corresponding to one of the classes. Monitors with a higher number of dead pixels are considered defective and must be replaced. On modern monitors with a TN film matrix, which is most susceptible to this disease, “hot” pixels are removed by the “remap” procedure (turning off individual pixels).
You can check your monitor for dead pixels by carefully inspecting the image, changing its solid fill to black, white, red, green, blue (in the Nokia Test program - the Color icon). The absence of “dots” of a different color in such a sequence certainly indicates the absence of dead pixels.
To make sure there are no “hot” and “dependent” pixels, it is additionally recommended to fill the monitor with “checkerboard”, as well as a mesh (in the Nokia Test program - the Moire icon, that is, moire).
“Dead pixels” in the video card
In some cases, defective video memory cells on the video card of a computer or other electronic device with a similar method for creating video images create a “dead pixel” effect on any type of monitor. Since usually only one bit is faulty, a characteristic feature of such a defect is that it depends on the applied video resolution, the color depth of a given video mode and the pixel color.
Links
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- Falkirk (city)
- Losev
See what “dead pixels” are in other dictionaries:
ISO 13406-2- ISO 13406 2 ISO standard for the visual ergonomics of LCD displays. The full title is “Ergonomic requirements for work with visual displays based on flat panels Part 2: Ergonomic requirements for flat panel displays.” Known to consumers... ...Wikipedia
LCD monitor
Burning out phosphor- Main article: Phosphor Phosphor burning is irreparable damage to the phosphor on the display screen of a CRT or plasma panel. Occurs due to overheating of a section of the phosphor coating followed by its evaporation, and is usually associated with... ... Wikipedia
LCD monitor- Liquid crystal display (also Liquid crystal display, LCD, LCD monitor, English liquid crystal display, LCD, flat panel indicator) is a flat monitor based on liquid crystals. LCD TFT (eng. TFT thin film transistor thin film... ... Wikipedia
TFT screen- Liquid crystal display (also Liquid crystal display, LCD, LCD monitor, English liquid crystal display, LCD, flat panel indicator) is a flat monitor based on liquid crystals. LCD TFT (eng. TFT thin film transistor thin film... ... Wikipedia
TFT display- Liquid crystal display (also Liquid crystal display, LCD, LCD monitor, English liquid crystal display, LCD, flat panel indicator) is a flat monitor based on liquid crystals. LCD TFT (eng. TFT thin film transistor thin film... ... Wikipedia
TFT monitor- Liquid crystal display (also Liquid crystal display, LCD, LCD monitor, English liquid crystal display, LCD, flat panel indicator) is a flat monitor based on liquid crystals. LCD TFT (eng. TFT thin film transistor thin film... ... Wikipedia
TN+Film- Liquid crystal display (also Liquid crystal display, LCD, LCD monitor, English liquid crystal display, LCD, flat panel indicator) is a flat monitor based on liquid crystals. LCD TFT (eng. TFT thin film transistor thin film... ... Wikipedia
LCD panel- Liquid crystal display (also Liquid crystal display, LCD, LCD monitor, English liquid crystal display, LCD, flat panel indicator) is a flat monitor based on liquid crystals. LCD TFT (eng. TFT thin film transistor thin film... ... Wikipedia
LCD- Liquid crystal display (also Liquid crystal display, LCD, LCD monitor, English liquid crystal display, LCD, flat panel indicator) is a flat monitor based on liquid crystals. LCD TFT (eng. TFT thin film transistor thin film... ... Wikipedia
In matrix devices consisting of a large number of identical cells, such as computer displays, it is not uncommon to encounter image defects that appear on only one cell or a small group of cells. The most common defects.
"Cold Pixels"
"Defective pixels"(also “dead” or “bad” pixels, the official name is defective pixels, English defective pixels) - a defect in an electronic device that perceives or reproduces an image and has a pixel structure. It manifests itself in the immutability of the output signal (luminance brightness in the case of a monitor, data in a digital file in the case of) several pixels.
The reason for the appearance of such a defect is a malfunction of the matrix element, in the case of a “dead pixel” - a constant malfunction. Since manufacturing a matrix is an expensive and time-consuming process, and it can be checked for malfunctions only after complete production, manufacturers try to reject products as rarely as possible, classifying them according to test results into one of the quality classes.
For electronic information storage devices (RAM, flash memory), the term “broken cell”, “faulty cell”, “faulty block” is traditionally used, since, unlike photographic and display devices, there is no obvious connection with the location of the defect in the image.
“Dead pixels” on photographic matrices
In the case of a matrix of a digital camera, video camera, scanner, document camera or other image-perceiving device, the output signal value is the numerical value of the corresponding pixel in the digital camera file. The vast majority of digital cameras provide masking of “dead pixels” by interpolating their values from neighboring ones (thereby turning them into “dependent” ones).
By most manufacturers, the presence of no more than 3 (some - 5) dead pixels is not considered a matrix defect.
The presence of a “line” of hot pixels, as well as groups of closely spaced hot pixels, is considered a matrix defect.
“Dead pixels” on monitors
The ISO 13406-2 standard establishes 4 quality classes for monitors based on the permissible number of dead pixels. Monitor sellers also set a certain threshold for their product, usually corresponding to one of the classes. Monitors with a higher number of dead pixels are considered defective and must be replaced. On modern monitors with a TN film matrix, which is most susceptible to this disease, “hot” pixels are removed by the “remap” procedure (turning off individual pixels).
You can check your monitor for dead pixels by carefully inspecting the image, changing its solid fill to black, white, red, green, blue (in the Nokia Test program - the Color icon). The absence of “dots” of a different color in such a sequence certainly indicates the absence of dead pixels.
To make sure there are no “hot” and “dependent” pixels, it is additionally recommended to fill the monitor with “checkerboard”, as well as a mesh (in the Nokia Test program - the Moire icon, that is, moire).
“Dead pixels” in the video card
In some cases, defective video memory cells on the video card of a computer or other electronic device with a similar method for creating video images create a “dead pixel” effect on any type of monitor. Since usually only one bit is faulty, a characteristic feature of such a defect is that it depends on the applied video resolution, the color depth of a given video mode and the pixel color.
Ways to recover stuck pixels
There are several basic ways to recover stuck pixels:
- Massage a “stuck” pixel. It is advisable to use a soft object with a small diameter (a cotton swab).
Combining the above methods is more effective than using them alone.
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Excerpt characterizing Dead Pixels
– I haven’t found him yet... But if he really exists, then he must be kind. And for some reason many people are afraid of him, they are afraid of him... At our school they say: “A man sounds proud!” How can a person be proud if fear hangs over him all the time?!.. And there are too many different gods - each country has its own. And everyone is trying to prove that theirs is the best... No, I still don’t understand a lot... But how can you believe in something without understanding?.. In our school they teach that there is nothing after death ... But how can I believe this if I see something completely different?.. I think blind faith simply kills hope in people and increases fear. If they knew what was really happening, they would behave much more carefully... They would not care what happens next after their death. They would know that they would live again, and they would have to answer for the way they lived. Just not in front of the “terrible God”, of course... But in front of yourself. And no one will come to atone for their sins, but they will have to atone for their sins themselves... I wanted to tell someone about this, but no one wanted to listen to me. It’s probably much more convenient for everyone to live this way... And probably easier too,” I finally finished my “deadly long” speech.I suddenly felt very sad. Somehow, this man managed to get me to talk about what had been “gnawing” at me inside since the day when I first “touched” the world of the dead, and in my naivety I thought that people needed to “just tell, and they will They will immediately believe and even be happy!... And, of course, they will immediately want to do only good things...” How naive a child do you have to be to have such a stupid and unrealizable dream born in your heart?!! People don't like to know that there is something else "out there" - after death. Because if you admit this, it means that they will have to answer for everything they have done. But this is exactly what no one wants... People are like children, for some reason they are sure that if they close their eyes and see nothing, then nothing bad will happen to them... Or blame everything on the strong shoulders to this same God, who will “atone” all their sins for them, and then everything will be fine... But is this really right?.. I was just a ten-year-old girl, but even then many things did not fit into my mind. my simple, “childish” logical framework. In the book about God (the Bible), for example, it was said that pride is a great sin, and the same Christ (the son of man!!!) says that with his death he will atone for “all the sins of man”... What kind of Pride one had to have , to equate yourself with the entire human race taken together?!. And what kind of person would dare to think such a thing about himself?.. Son of God? Or the Son of Man?.. And the churches?!.. Each one more beautiful than the other. It’s as if the ancient architects tried very hard to “outdo” each other when building God’s house... Yes, churches really are incredibly beautiful, like museums. Each of them is a real work of art... But, if I understood correctly, a person went to church to talk with God, right? In that case, how could he find him in all that stunning, eye-catching gold luxury, which, for example, not only did not dispose me to open my heart, but, on the contrary, to close it as quickly as possible, so as not to see the same himself, bleeding, almost naked, brutally tortured God, crucified in the middle of all that shiny, sparkling, crushing gold, as if people were celebrating his death, and did not believe and did not rejoice at his life... Even in cemeteries, we all plant the living flowers so that they remind us of the life of the same dead. So why didn’t I see a statue of the living Christ in any church, to whom I could pray, talk to him, open my soul?.. And does the House of God mean only his death? .. Once I asked the priest why we don’t pray to the living God? He looked at me like I was an annoying fly and said that “this is so that we do not forget that he (God) gave his life for us, atoning for our sins, and now we must always remember that we are not his.” worthy (?!), and to repent of their sins as much as possible”... But if he has already redeemed them, then what should we repent of?.. And if we must repent, does that mean all this atonement is a lie? The priest got very angry and said that I had heretical thoughts and that I should atone for them by reading “Our Father” twenty times in the evening (!)... Comments, I think, are unnecessary...
I could continue for a very, very long time, since all this irritated me very much at that time, and I had thousands of questions to which no one gave me answers, but only advised me to simply “believe,” which I would never do in my life I couldn’t, because before I believed, I had to understand why, and if there was no logic in that same “faith,” then for me it was a “search.” black cat in a black room,” and neither my heart nor my soul needed such faith. And not because (as some told me) I had a “dark” soul that did not need God... On the contrary, I think that my soul was light enough to understand and accept, but there was nothing to accept ... And what could be explained if people themselves killed their God, and then suddenly decided that it would be “more correct” to worship him?.. So, in my opinion, it would be better not to kill, but to try to learn from him as much as possible, if he really was a real God... For some reason, at that time I felt much closer to our “old gods”, whose carved statues were erected in our city, and throughout Lithuania, a bunch of. These were funny and warm, cheerful and angry, sad and stern gods, who were not as incomprehensibly “tragic” as the same Christ, for whom they built amazingly expensive churches, as if really trying to atone for some sins...
Purchasing a computer, laptop or other gadget is a responsible undertaking. Even new technology can have obvious and hidden defects. Dead (or dead) pixels are a common malfunction that disrupts the integrity of the image on the display. If a single cell does not work, then a change in image quality is usually not detected by the naked eye. But if a group of pixels is damaged, then the perception of the picture is disrupted.
Defective pixels form a black, white or colored dot, which is distracting when working on a PC and interferes with watching videos. The reason for the formation of the defect is the malfunction of the matrix elements. In this regard, every potential buyer of an electronic device needs to know how to check a monitor for dead pixels.
Checking your monitor for defective pixels
Experts offer several ways to check your monitor for dead pixels. Let's consider the most reliable of them.
Monitor Inspection
The easiest way is to carefully inspect the screen. To visually determine whether there are defective pixels, do the following:
- wipe the display to remove dust and possible fingerprints;
- set the optimal resolution level;
- Using a plain background (screen fill), we alternately change achromatic colors (white, black) and primary chromatic colors (red, yellow, blue, green).
Screen color changing function is provided software. So, for example, in the Windows 10 version, the color fill is done this way:
- go to the “Settings” application, select the “Personalization” section;
- set “Solid color” in the “Background” subsection;
- click “Additional color”, choosing a white or light gray shade from the color palette;
- After clicking “Finish”, go to the “Taskbar” and enable the “Automatically hide the taskbar in desktop mode” function.
Each time you change the background, you should carefully inspect the monitor for blank or glowing dots. Their detection indicates matrix defects.
Using Utilities
When testing your monitor for dead pixels, you can use special utilities. Among the popular utilities for searching for dead pixels are:
IsMyLcdOK
Many experts consider IsMyLcdOK one of best utilities, designed to identify defective pixels. You can download the test program from the resource http://www.softwareok.com/?Download=IsMyLcdOK.After the test utility is launched, you should press numbers from 1 to 9 on the keyboard. As you press the next number, the screen will flood a certain color. If you look closely at the monitor, after 2–4 fills you can notice damaged pixels. The program is compatible with all Windows versions and takes up 30 KB, so it can be downloaded to a flash drive and then run on any computer.
Monitor test
The program, supported by all versions of Windows, allows you to quickly find dead pixels. To start testing, after launch you should change the fill color mode and change pictures. If desired, you can use automatic mode, simply by pressing the letter A on the keyboard. In auto mode, the pictures on the screen will change independently at certain intervals. You can download the test at https://dps.uk.com/software/dpt.Online services
Online services are used to detect dead pixels. The principle of their operation is the same as that of utilities, but to check they need to be connected to the Internet, which is not a problem in specialized stores. During testing, the screen fill color also changes, and you only need to carefully monitor the image so as not to miss a possible defect.Monteon
Among the popular online services is Monteon, located on the website http://monteon.ru. By using of this service You can perform a universal monitor test. There are tests for sharpness, contrast, color rendition, and, of course, to search for dead pixels. The resource launch algorithm is as follows:- on home page Click the “Start” button, after which the full-screen viewing mode will open;
- By clicking on the arrows or simply clicking in the center of the page, we scroll through the slides, carefully observing whether a black dot has appeared, which is a dead pixel.
CatLair
The CatLair website is very convenient for identifying dead pixels. Resource address: http://monitor.catlair.ru. In addition to searching for defective matrix cells, the online service makes a number of options available: color balancing, adjusting picture stability, and setting the display synchronization frequency. Testing is carried out as follows:- Having gone to the site page, press the F11 key to expand the window to fit the display;
- By clicking sequentially on the icons on the control panel, you change the background images.
Each test is accompanied by detailed description indicating what to look for when checking.
There are other utilities and online services that you can use to diagnose your monitor. As you have seen, checking the integrity of the matrix yourself when purchasing an electronic device is not at all difficult.
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 the program Dead Pixel Tester required:
![](https://i2.wp.com/okeygeek.ru/wp-content/uploads/2018/03/22.jpg)
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:
![](https://i2.wp.com/okeygeek.ru/wp-content/uploads/2018/03/3.jpg)
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 this service to work, you will need to have it 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:
![](https://i2.wp.com/okeygeek.ru/wp-content/uploads/2018/03/bad.jpg)
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.
Nowadays, any user of modern household and computer equipment the phrase “dead pixels” causes nothing but headaches and bad mood. But what is it really and how scary is it to be the “lucky” owner of equipment with these same dead pixels?
First, let's figure out what principles they work on. modern televisions and monitors. They form an image using many dots, which are called pixels. When they change their color, the image on the screen also changes, and we see the picture formed from these dots. In modern monitors, a matrix is installed, called active - in it, a separate thin-film transistor is responsible for controlling each pixel (that is why such screens are called TFT, from English. If one of these transistors fails for some reason, we can observe the phenomenon which is called a dead pixel on the monitor.
Due to a technical malfunction of the transistor, such dots do not change their color when the image on the screen changes and appear as a black dot. Although it should be taken into account that dead pixels can be not only black - on a black background such a dot is usually white, and there are also red, blue and green faulty pixels. In our time, such a malfunction can be corrected in a specialized workshop. To do this, it is necessary to replace the corresponding failed transistor, and it will again be able to perform its functions.
But it happens that dead pixels on the monitor are formed not due to the failure of the transistor, but due to the so-called stuck dots. Usually a jam is accompanied by the appearance of a light dot on the dark background, which does not change its color under any circumstances. Such a defect, unlike a “black spot,” can be tried to be corrected at home using some physical or software manipulations.
It should also be noted that the world's leading manufacturers are currently establishing special standards that allow a certain number of faulty pixels in various standards. This is due, first of all, to the fact that the percentage of defects among matrices operating on liquid crystals is quite high. You should pay attention to this nuance if you are going to contact a repair shop under warranty. A table of acceptable defective pixels is included in the standard called "ISO-13406". It can be easily found on the Internet on the websites of many leading manufacturers of LCD monitors.
Many users often have a question: how difficult is it to see dead pixels with the naked eye? It is unlikely that it will be possible to answer this unambiguously. This is due to the fact that when buying a monitor, sellers very often show us bright, changing images, thereby not allowing us to properly examine the display in different situations. For example, it happens that a defective red dot can only be seen on a green background, and even then a certain shade. Therefore, you should check your purchase very carefully. This can also be done using special programs. One of the best such utilities is “Nokia Monitor Test”, which allows you to test your monitor for various defects, readability, moire and damaged pixels.
Don’t forget that you can try to “cure” the so-called stuck dead pixels (not black dots, but colored dots) at home. To do this you can use like special programs(one of the best such utilities is called “ScreenFix Deluxe”) or try massaging the defective area of the display with a cotton swab. The main thing is not to overdo it during such a “massage”, since the chance of further damaging the display or its anti-glare coating is quite high.