Philips C221V2SB/01, Service Manual

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Meridian 2
4.3 Pixel Defect Policy
Philips strives to deliver the highest quality products. We use some of the industry's most advanced manufacturing
processes and practice stringent quality control. However, pixel or sub pixel defects on the TFT LCD panels used
in flat panel monitors are sometimes unavoidable. No manufacturer can guarantee that all panels will be free from
pixel defects, but Philips guarantees that any monitor with an unacceptable number of defects will be repaired or
replaced under warranty. This notice explains the different types of pixel defects and defines acceptable defect
levels for each type. In order to qualify for repair or replacement under warranty, the number of pixel defects on a
TFT LCD panel must exceed these acceptable levels. For example, no more than 0.0004% of the sub pixels on a
22 ″ XGA monitor may be defective. Furthermore, Philips sets even higher quality standards for certain types or
combinations of pixel defects that are more noticeable than others. This policy is valid worldwide.
Pixels and Sub pixels
A pixel, or picture element, is composed of three sub pixels in the primary colors of red, green and blue.
Many pixels together form an image. When all sub pixels of a pixel are lit, the three colored sub pixels together
appear as a single white pixel. When all are dark, the three colored sub pixels together appear as a single black
pixel. Other combinations of lit and dark sub pixels appear as single pixels of other colors.
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Types of Pixel Defects
Pixel and sub pixel defects appear on the screen in different ways. There are two categories of pixel defects and
several types of sub pixel defects within each category.
Bright Dot Defects Bright dot defects appear as pixels or sub pixels that are always lit or ‘on’. That is, a Bright dot is
a sub-pixel that stands out on the screen when the monitor displays a dark pattern. There are three types of bright
dot defects:
Two adjacent lit sub pixels:
- Red + Blue = Purple Three adjacent lit sub pixels
(one white pixel) One lit red, green or blue sub pixel - Red + Green = Yellow
- Green + Blue = Cyan (Light Blue)
A red or blue bright dot must be more than 50 percent brighter than neighboring dots while a green bright
dot is 30 percent brighter than neighboring dots.