What Is a Black Spot on a LCD TV?
Black spots on an LCD television can interfere with picture quality and viewing experience, especially if located in the center. In the best case scenario, black spots are caused by dirt, dust, or debris that has collected on the screen surface. However, dead or stuck pixels caused by internal malfunctions can also lead to black spots. The best approach is to identify exactly what is causing the spots on your screen before taking the designated approach to fix it.
Before assuming the spots on your LCD screen are caused by internal malfunctions, clean the entire screen following the manufacturer's recommendations in your user manual. If these are not provided, use a soft cloth and a 50/50 solution of water and alcohol to gently rub problem areas, as well as the entire screen. Never use paper towels as these are abrasive and will cause more screen damage.
Dead or Stuck?
An LCD pixel contains three sub-pixels of red, green and blue, that are capable of changing colors and displaying each color at 256 shades, or gray levels. If a pixel becomes stuck in the closed position at gray level 0, it will appear completely black. A pixel will also appear black if it is dead, but it is important to identify the cause, since dead pixels are a much more serious issue and often require replacement. If you see a pixel is still able to change colors, even slightly from its normally black appearance, then it is stuck and not dead. Specialized display software or DVDs can help you identify this, as well as changing the background color of your TV to solid colors, preferably white to identify black spots.
Dead pixels can occur as a result of blunt force trauma to the screen, non-functioning transistors or manufacturer defects. Stuck pixels can also occur from trauma, or from uneven phosphorus wear, caused by leaving static images on the screen for long periods of time.
Stuck pixels can sometimes be repaired by running special DVD programming designed to exercise pixels from their stuck position. Also, gently rubbing the affected area with a soft cloth while this programming is running can also help un-stick the pixel. Dead pixels usually require a replacement screen or a professional repair solution. Luckily, most manufacturers expect a certain number of dead pixels to occur over the life of their product, and many offer replacement screens if the number of dead pixels exceeds their expectation. This is something to keep in mind when shopping for an LCD TV, and some manufacturers like Panasonic offer a warranty on all pixels.