Philips BDL4221V/00, Service Manual

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8 420WN6 LCD TV
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Philips' LCD Panel Pixel Defect Policy
Philips strives to deliver the highest quality products.We use some of the
industry's most advanced manufacturing processes and practise
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 15" 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 coloredsubpixels
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)
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:
One dark sub pixel Two or three adjacent dark sub pixels
Proximity of Pixel Defects
Because pixel and sub pixels defects of the same type that are near to
one another may be more
noticeable, Philips also specifies tolerances for the proximity of pixel
defects.
Pixel Defect Tolerances
In order to qualify for repair or replacement due to pixel defects during
the warranty period, a TFT LCD panel in a Philips flat panel monitor
must have pixel or sub pixel defects exceeding the
tolerances listed in the following tables.
BRIGHT DOT DEFECTS ACCEPTABLE LEVEL
MODEL 420WN6
1 lit sub pixel 0
2 adjacent lit sub pixels 0
3 adjacent lit sub pixels (one white pixel) 0
75% ~ 50% of Dot 0
50% ~ Less Dot (Weak Dot) Max 7
Distance between two bright dot defects* N/A
Total bright dot defects of all types 0
Tiny bright dots less then 50% R/B, 30% G Ma
Max4
*Bright Dot is defined as dots (sub-pixels) which appeared brightly in the
screen when the LCM displayed with whole pattern & Bright Dot's
brightess is defined over 50% of the brightness against around. (but,
Green bright dot is over 30% of brightness against around)
*Here in Tiny Bright Dot is defined as "for Red and Blue" the bright area
should be no longer than1/2 sub-pixel and for green the bright area
should be no larger than 1/3 sub-pixel.
BLACK DOT DEFECTS ACCEPTABLE LEVEL
MODEL 420WN6
1 dark sub pixel 5 or fewer
2 adjacent dark sub pixels 1 or fewer
3 adjacent dark sub pixels 0
Distance between two black dot defects* 15 mm or more
Total black dot defects of all types 5 or fewer
TOTAL DOT DEFECTS ACCEPTABLE LEVEL
MODEL 420WN6
Total bright or black dot defects of all types 5 or fewer
Note:
* 1 or 2 adjacent sub pixel defects = 1 dot defect
All Philips monitors are ISO13406-2 Compliant
Philips Pixel Defect Policy