Philips BDL5545E/00 User Manual page 51

User Manual BDL5545E
MURA
Dark spots or patches may occasionally appear on some liquid crystal display (LCD) panels. This is known
within the industry as Mura, which is a Japanese term for "unevenness." It is used to describe an irregular
pattern or area in which uneven screen uniformity appears under certain conditions. Mura is a result of the
deterioration of the liquid crystal alignment layer and is most commonly caused by long-term operation under
high ambient temperatures. It is an industry- wide phenomenon and Mura is not repairable. It is also not
covered by our warranty terms. Mura has been around since the introduction of LCD technology and with
screens getting bigger and in operation 24/7, many displays are running in low light conditions. This all adds to
the possibility of Mura affecting displays.
HOW TO SPOT MURA
There are many symptoms of Mura and also multiple causes. Several of these are listed below:
• Impurities or foreign particles in the crystal matrix
• Uneven distribution of LCD matrix during manufacturing
• Non-uniform luminance distribution of the backlight
• Panel assembly induced stress
• Flaws within the LCD cells
• Thermal induced stress - high temperature operation over long periods of time
HOW TO AVOID MURA
Although we can not guarantee the complete eradication of Mura every time, in general the appearance of
Mura can be minimized by these methods:
• Lower the backlight brightness
• Use a screen saver
• Reduce the ambient temperature around the unit
50