Definition Of Pixel Defects - Philips 190EW9FB 00 Service Manual

10 190EW9 LCD
Adjust the contrast and brightness on On-Screen
The screen is too Display.(The backlight of the LCD monitor has a
bright or too dark fixed life span. When the screen becomes dark or
begins to flicked, please contact your sales
representative).
If an image remains on the screen for an
An after-image
appears
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
This is characteristic of liquid crystal and is
remains after the
not caused by a malfunction or deterioration
power has been
of the liquid crystal. The after-image will
turned off
disappear after a peroid of time.
The remaining dots are normal
Green, red, blue,
characteristic of the liquid crystal used in
dark, and white dots
today's technology.
remains
For further assistance, refer to the Consumer Information
Centers list and contact your local Philips distributor.

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.
subpixel
subpixel
R
R G
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.
Definition of Pixel Defects
subpixel
G B
B
Pixel
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
Bule+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
G
R B
P
Y
C
W