Pixel Defect Policy - Philips 240S4LPMS/00 Service Manual

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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
Monitor 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 Monitor panel must exceed these
acceptable levels. For example, no more than
0.0004% of the sub pixels on a 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.
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 the types of bright
dot defects.
One lit red, green or blue sub pixel.
Two adjacent lit sub pixels:
- Red + Blue = Purple
- Red + Green = Yellow
- Green + Blue = Cyan (Light Blue)
Three adjacent lit sub pixels (one white pixel)
Note:
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.
Black Dot Defects Black dot defects appear as pixels
or sub pixels that are always dark or 'off'. That is, a
dark dot is a sub-pixel that stands out on the screen
when the monitor displays a light pattern. These are
the types of black dot defects.