Thursday, April 19, 2007

HDTV Clouding or Mura

Clouding (aka "mura") on an LCD HDTV:

The issue of clouding is easy to understand, but more difficult to explain why it occurs and what causes it. By looking at the picture below left, you can see the back light that is present in LCD's. The picture on the right shows the TV in the forefront that has an even back light, while the one in the background has "cloud" patches caused by an uneven back light. The reason why this issue is specific to LCD's is because it is the only display that uses a back light to produce the picture. It's important not to confuse this with the back lights that some Plasmas have. The Plasma back light is an aesthetic feature which shines a light towards the wall behind the display to luminate the outside area of the plasma. What causes the clouding or Mura (a Japanese word for uneven uniformity), is down to the back light, various issues with the LCD matrix, and human error on the assembly line.