Philips 170M4FS/00, Service Manual

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170T4
Definition of Pixel Defects
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 colored subpixels
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 appear as pixels or sub pixels that are always lit or
'on'. These 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)
Black Dot Defects
Appear as pixels or sub pixels that are always dark or 'off'. These are
the types of black dot defects:
One dark sub pixel Two or three adjacent dark sub pixels
Proximity of Pixel Defects
Pixel Defect Tolerances
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.
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.
Note: 1 or 2 adjacent sub pixel defects = 1 dot defect
BRIGHT DOT DEFECTS ACCEPTABLE LEVEL
MODEL
150T4/170T4
1 lit sub pixel 4 or fewer
2 adjacent lit sub pixels 2 or fewer
3 adjacent lit sub pixels (one white pixel) 0
Distance between two bright dot defects* 15 mm or more
Total bright dot defects of all types 4 or fewer
BLACK DOT DEFECTS ACCEPTABLE LEVEL
MODEL
150T4/170T4
1 dark sub pixel 4 or fewer
2 adjacent dark sub pixels 2 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 4 or fewer
TOTAL DOT DEFECTS ACCEPTABLE LEVEL
MODEL
150T4/170T4
Total bright or black dot defects of all
types
5 or fewer