Dead spots on the laptop screen

Each laptop company has set a standard parameter for the number of acceptable dead spots on the screen. If the number of dead points actually exceeds the permitted standard, the user has the right to request warranty. However, not everyone knows that.

Screen technology commonly used in laptops on the market today is LCD liquid crystal display.

Different types of screens are distinguished by size and resolution. Resolution is determined by the number of dots (pixels). Each dot on the LCD screen is composed of three sub-dots of red points, green points and blue points. These three colors are combined to form the complete color to display.

Resolution is a measure of screen visibility. For example, a standard 14.1-inch XGA screen will have a resolution of 1024 x 768 pixels, of which 1,024 is the horizontal dot score and 768 is the vertical dot screen. Meanwhile, the standard 14.1-inch SXGA screen will have a resolution of 1,280 x 1,024 pixels. If an image on the XGA screen is 20 x 10 pixels in size, then on the SXGA screen, it will be smaller in size, although the dot score used for display is the same. This helps the SXGA screen display more images, creating a wider feel than the XGA screen.

Most laptop screens now use TFT display technology.Photo: Hoang Ha

Most LCD monitors currently use TFT (Thin-Film Transistor) technology, or active matrix display, to distinguish it from passive display technology (passive matrix display). ).

The TFT screen uses a separate transistor (transistors) at each spot, which is triggered by a very small current, which makes the color display speed at each dot point faster. Therefore, with active display, changes in color or images will be displayed truthfully and much faster than passive screens.

If a transistor is turned off or open, the dot there will not be able to display normal colors. At that time, this point is called a dead pixel. Dead spots can be bright colors, meaning that only one color is shown as red, blue or white, or it can be completely lost, only black is visible.

During the manufacturing process, it is difficult to determine if any transistor is broken. Usually only when a screen has been produced completely, can it determine how many dead spots it has.

If manufacturers are forced to eliminate screens with dead spots, the cost of production and the corresponding price of the product will be very high. Therefore, each manufacturer will set a specific standard for the number of acceptable dead spots on their screens. For example, with Lenovo, the number of dead spots allowed is determined according to the type of screen, but generally falls between 5 and 6 dots. This means, if there are more dead spots on Lenovo laptop screens than these allowable numbers, users have the right to request a screen warranty.

Therefore, in order to ensure maximum benefit from the manufacturer's services, consumers should carefully understand the information on the number of screen points covered by each manufacturer.

In addition, the warranty of screen dots depends on distributors as well as retailers. You should know the relevant information to know when you can warranty the monitor, when not.

Mr. Linh