Philips 200VW8FB service manual Definition of Pixel Defects, One dark sub pixel

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200VW8 LCD

Definition of Pixel Defects

	Adjust the contrast and brightness on
The screen is too bright or	OSD Main Controls.
	(The backlight of the LCD monitor has a fixed
too dark
	life span. When the screen becomes dark or
	begins to flicker,please contact your dealer).
	If an image remains on the screen for an extended
An after-image appears	period of time, it may be imprinted in the screen
	and leave an after-image. This usually disappears

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:

	after a few hours.
	This is characteristic of liquid crystal and is not
An after-image remains after	caused by a malfunction or deterioration of the
the power has been turned off	liquid crystal. The after-image will disappear after
	a peroid of time.
Green, red, blue, dark, and	The remaining dots are normal characteristic of
white dots remains	the liquid crystal used in today’s technology.

For further assistance, refer to the Consumer Information Centers list and contact your local Philips distributor.

Definition of Pixel 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)

G

R

B

P

Y

C

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 subpixel

Three adjacent lit sub pixels	W
(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:

R G B One dark sub pixel

R G B

Pixel

Two or three adjacent dark sub pixels

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.