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5.5. Pixel Defect Tolerances
In order to qualify for repair due to pixel defects during the warranty period, a PDP / TFT panel in a Plasma / LCD-
display must have pixel or sub-pixel defects exceeding the tolerances listed in the following table.
BRIGHT DOT EFFECT ACCEPTABLE LEVEL
1 lit sub pixel 2
BLACK DOT EFFECT ACCEPTABLE LEVEL
1 dark sub pixel 10
TOTAL DOT DEFECTS 12
5.6. 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