What causes dark lines to appear on an LCD television?
When you turn on your LCD TV to watch your favorite show, the last thing you want to see is a problem on the screen. LCD televisions (for its acronym in English, liquid crystal display) are susceptible to the appearance of black lines, horizontally and vertically. These problematic lines are caused from an inadequate adjustment even by technical problems.
LCD televisions do not light on their own; instead, they are transmitters, which means they need another source to illuminate the image on your screen. CCFLs (cold cathode fluorescent lamps) and LEDs, light emitting diodes, are the two main types of backlighting for LCD televisions. LED technology offers a brighter image and darker blacks than CCFL-based backlighting. Even so, LED technology is far from perfect. Some LCD TVs use several LED lights to illuminate the screen. Sometimes, the LED light is in the central part of the screen, while sometimes there are four separate lights in each corner of the screen. In cases like this, you can see a dim and dark edge between the corners;
The TAB fault (automatic link tape) can happen when your LCD television is damaged due to a fall or other impact. The TAB connects the television’s control board (similar to the “brain” of LCD television), with invisible layers of electrodes that send electrical currents through the liquid crystals, which produce the colors you see on your screen. When your LCD suffers from the TAB fault, the “brain” of the television is disconnected from the electrode layers causing rows or entire columns of electrodes to become dark. This results in a thin, completely black line that crosses the entire screen, either from left to right or from top to bottom.
Failure of control board synchronization
Another important part of your LCD television is the timing of the control board, sometimes called the T-CON board. This board is part of the LCD screen, and helps to digitize the information received from the television processor to a format that the screen can understand at the pixel level. When this component fails, the images on your screen may be distorted because the coordination and synchronization between the different parts of the screen will not be the same. This can produce horizontal or vertical lines on your screen, but rather leads to pixilation. Replacing the T-CON board (which means replacing the full screen) is the only way to remedy the problem.
- Microchip: LCD Design Center (LCD Design Center)
- ViewSonic: Europe Limited Pixel Policy (Limited Pixel Policy in Europe)
- LCD TV Buying Guide: LCD TV Calibration (Calibration of LCD TVs)
- The New York Times: What’s An LED TV? (What is an LED TV?)