10
190VW8 LCD
Definition of Pixel Defects
Definition of Pixel Defects
This section explains the different types of pixel defects and
defines acceptable defect levels of each type. In order to
quality for repair or replacement under warranty, the number
of pixel defects on a TFT LCD panel must exceed these
acceptable levels.
1. Definition of 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.
2. 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
Three adjacent lit sub pixels
(one white pixel)
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:
Two or three adjacent
dark sub pixels
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.
subpixel
R
R
G
B
Pixel
R
G
B
Y
C
W
The screen is too bright
or
too dark
Adjust the contrast and brightness on On-Screen
Display.(The backlight of the LCD monitor has a fixed life
span. When the screen becomes dark or begins to flicked,
please contact your sales representative).
An after-image appears
If an image remains on the screen for an extended
period of time, it may be imprinted in the screen
and leave an after-image. This usually disappears
after a few hours.
An after-image remains
after
the power has been
turned off
This is characteristic of liquid crystal and is not
caused by a malfunction or deterioration of the
liquid crystal. The after-image will disappear after
a peroid of time.
Green, red, blue, dark,
and
white dots remains
The remaining dots are normal characteristic of
the liquid crystal used in today’s technology.
For further assistance, refer to the Consumer Information Centers list
and contact your local Philips distributor.
