Despite the fact that every year the technology for the production of LCD TVs is constantly being improved, there is still a risk of buying defective TVs with broken pixels.
That is why, before the transaction, a plasma display should be diagnosed for the presence of such “surprises”. And today we will consider what kind of program there is to check the TV for broken pixels and how you can use it.
A few words about pixels
A pixel is the smallest detail of a digital image or display matrix. It is an indivisible object of a round (most often rectangular) shape. It is the pixels that form the image on the screen of a monitor or TV.
The process of manufacturing plasma screens is very complex and time-consuming, requiring high precision and expensive tools. LCD displays are used in almost all digital devices. This can be cameras, mobile phones, laptops, monitors for PCs, televisions and navigators.
Crystals
The basis of plasma TVs and LCD monitors are liquid crystals. Light is transmitted through them, from which the image is then obtained. Often the outer layer of the LCD panel is made of glass. In this case, between the polarizing filters and the panel there is a thin-film transistor, as well as a layer of crystals with a backlight module inside. The latter can be both rear and side. During TV operation, light passes through a layer of crystals, which is instantly converted into a finished image.
Subpixels
The pixel itself consists of several subpixels (blue, green and red). With the help of them, the LCD screen can distinguish millions of the most diverse colors and shades, the crystal molecule behaves as part of any liquid substance, that is, is constantly in motion.
Diagnostic program for dead pixels on the TV
There are currently two of the most popular utilities for diagnosing and checking LCD displays for dead pixels:
- TFTTest.
- DeadPixelTester
Using them is pretty simple. Below we will tell how the TV is checked for broken pixels from a flash drive with both programs.
So, we have a flash drive and the TFTTest utility. First you need to record the desired software package. It should include both the program itself and a separate archive with a set of color fills and gradients with a resolution of 1920 x 1080 pixels. You can also download a set of videos with which you can see how the TV perceives and displays a picture in 3D and the quality of drawing (from 100 to 800 Hertz).
Next, install the USB flash drive into the USB port of the TV. Using the remote control, go to the menu and connect the drive. Next, choose a photo view by selecting pre-prepared color fills. Most often in the archives there are 9 such fills with yellow, black, white, green and other colors. We start the utility and take turns looking through all the photos. If there are defects on the LCD display, we will immediately notice them on the screen - they will differ in a shade from the general fill background (or they will be automatically detected by the program for checking the TV for broken pixels). It is also recommended to check the quality of the reproduced sound and the depth of contrast of the picture itself. So you can determine exactly whether this TV is defective or not.
DeadPixelTester, a program for checking your TV for broken pixels, was also created to test LCD screens. Thanks to it, you can highlight any dubious areas of the screen with any of the colors suggested by the program.
To do this, the program for checking the TV for broken pixels will require you to select any color you like and check its display quality on the entire display area. If a broken pixel is detected, you can go to the window with 5 basic shades. So you will examine the suspicious area in more detail.
How much does a professional check for dead pixels of a TV cost
Oddly enough, but in electronics stores you can offer professional TV diagnostics for such defects. There is nothing distinctive in it - all actions are similar to those that you do with your own hands. True, for this they will require from you 600 to 1000 rubles. For independent verification, you only need a flash drive and Internet access, from where you can download the necessary utilities and fill colors.
Dead pixels are normal or not.
In fact, manufacturers allow defective TVs to enter the market, however, their concentration of 1 million pixels should not go beyond certain limits. First-class liquid crystal displays do not allow the presence of such defects. Most often, these are very expensive and rare TV models that are not very popular and in demand on the world market. The second class allows the presence of no more than two defects of type I and II per one million pixels. This class is the most popular in the Russian market. The third class allows the presence of up to 5 broken pixels of I and II grades, as well as up to 50 III grades. The fourth may contain up to 500 defects of various types, however, such televisions have not yet been met in Russian electronics stores.
So, we found out how the screen is checked for broken pixels, and also what is the norm of their content on TVs of various types.