Operating instructions

English 24
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 colors (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 belonging 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
1280 x 720 (17” wide) 0.921600 2.764800 2 2 5 - 2
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
Rows
Blue
Green
Red