Pixel Errors In The Tft Monitor - Medion AKOYA E54001 Anleitung

Pixel errors in the TFT monitor

A total of approx. 6.9 m control transistors are used in the case of Active Matrix TFTs with a resolution of 1680 x
1050 Pixeln (WSXGA), each composed of three sub-pixels (red, green, blue). A failure or incorrect control of
pixels or individual sub-pixels can arise occasionally, because of this very high number of transistors and the
extremely complex manufacturing process associated with it.
There have been continuous approaches to define the number of permitted pixel errors in the past. However,
these attempts have for the most part been very complicated and completely different from manufacturer to
manufacturer. MEDION follows the strict and transparent requirement of the ISO 13406-2, Class II Norm, which
are summarised in brief in the following, in the handling of guarantees for all TFT display products for this reason.
Among other matters, the 13406-2 ISO Standard defines generally applicable
guidelines in relation to pixel errors. The pixel errors are categorised into four
error classes and three types of error. Each individual pixel is composed in its
turn of three sub-pixels each with a basic colour (red, green, blue).
Types of pixel error:
 Type 1: Pixels shining for a long time (bright, white point), although not activated.
A white pixel arises because of the illumination of all three sub-pixels.
 Type 2: Pixels not shining (dark, black point), although activated
 Type 3: Abnormal or defective sub-pixels coloured red, green or blue (e.g. shining for a long time with half
brightness, not lighting one colour, flashing or flickering, but not Type 1 or 2)
Addition: Cluster of Type 3 (= failure of two or more sub-pixels in a block of 5 x 5 pixels. A cluster is a field of 5 x 5
pixels (15 x 5 sub-pixels).
Classes of pixel error:
Error Class
The permitted number of errors of the types specified above in each class of error relates to a million pixels and
must be converted in accordance with the physical resolution of the display.
A maximum permitted number in Error Class II follows from this:
For a resolution of
1024 x 768 (15")
1280 x 1024 (17,18, 19")
1600 x 1200 (19")
1440 x 900 (19" wide)
1680 x 1050 (20" wide, 22" wide)
1920 x 1080 (23.6" wide)
1920 x 1200 (25.5" wide)
Error Class I is only used in the case of special applications, e.g. in the medical sector, and is associated with
corresponding supplementary costs. Error Class II has become established as the standard for manufacturers
conscious of quality and with very good display units.
Type 1 Type 2
I 0
II 2
III 5
IV 50 150
M. pixel
0.786432
1.310720
1.920000
1.296000
1.764000
2.073600
2.304000
Pixel errors in the TFT monitor
Type 3 Cluster of Type 3
0 0 -
2 5 -
15 50
500
Sub-pixels
2.359296
3.932160
5.760000
3.888000
5.292000
6.220800
6.912000
0
2
5
50
(Type, see
above)
2 2 4 - 2
3 3 7 - 3
4 4 10 - 4
3 3 7 - 3
4 4 10 - 4
4 4 10 - 4
4 4 10 - 4
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