Operating instructions

Specifications
17
Pixel Defects on TFTs (LCD-Displays)
Active matrix TFTs (LCD) with a resolution of 1680 x 1050 pixel (WSXGA), which are in turn composed of
three sub-pixels each (red, green, blue), contain about 5.3 million addressable transistors. Because of this very
high number of transistors and their extremely complex production process occasionally defective or incorrectly
addressed pixels or sub-pixels may occur.
There have been several attempts in the past to define the acceptable number of defective pixels. But this can be
difficult and varies widely between different manufacturers.
MEDION, therefore, adheres to the clear and strict requirements of ISO
13406-2, class II, for the warranty handling of all TFT display products.
These requirements are summarized below.
Within ISO-standard 13406-2 the general requirements regarding pixel defects
are defined. Pixel defects are classified into three failure types and four failure
classes. Each individual pixel is made up of three sub-pixels in the primary col-
ors (red, green, blue).
Types of Pixel Failures:
Type 1:
A constantly lit pixel (a bright, white spot), even though it is not addressed
A white pixel is caused when all three sub-pixel are lit.
Type 2:
A pixel that does not light up (dark, black spot), although it is addressed
Type 3:
Abnormal or defective red, green or blue sub-pixels.
(E.g. constantly lit with half the brightness, one color is not shining, blinking or flickering, but not belong-
ing to Type 1 or 2 Pixel Failures)
In addition: A cluster of type 3 (= 2 or more defective sub-pixels in an array of 5 x 5 pixel). A cluster is an array
of 5 x 5 pixel (15 x 5 sub-pixel).
Classes of Pixel Failures:
Failure class Type 1 Type 2 Type 3 Cluster v. Type 3
I 0 0 0 - 0
II 2 2 5 - 2
III 5 15 50 5
IV 50 150 500 50
The acceptable number of defects of the above mentioned types in each failure class refers to one million pixels
and has to be calculated according the physical resolution of the display.
This leads to a maximum allowed number in class II type failure:
Resolution Mn Pixel Sub-Pixel (Type s. above)
1024 x 768 (15") 0.786432 2.359296 2 2 4 - 2
1280 x 1024 (17,18, 19") 1.310720 3.932160 3 3 7 - 3
1600 x 1200 (19“) 1.920000 5.760000 4 4 10 - 4
1440 x 900 (19“ wide) 1.296000 3.888000 3 3 7 - 3
1680 x 1050 (20“ wide, 22“ wide) 1.764000 5.292000 4 4 10 - 4
Class I type failure only applies to special applications, e.g. medical applications, and results in corresponding
price increases. Class II type failure is the established standard for quality conscious manufacturers with high qual-
ity displays.
Rows
Blue
Green
Red