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N-LINE OWNERS MANUAL
Type 4) fault cluster, the number of defective pixels in a 5 x 5 pixel square.
Class I monitors are guaranteed products which do not have any defects at all .
Class II specification consists of the following faults permissible: 2 x Type 1, 2 x Type 2, 5 x Type 3 and 2 x Type 4.
Nottrot BV delivers TFT Monitors in accordance to ISO 13406-2 Class II. Special arrangements can be made.
The number of permissible pixel faults can be calculated with the following function:
(number of errors = number of pixels of the physical resolution x number of errors in the pixel fault category /
1.000.000) with rounding up upward
(there it no half errors gives).
The following table defines the maximum permissible number of pixel faults for the respective resolution types validly
for the pixel error class II.
Panel
type
Physical
Resolution
Number
of pixel
Maximally permissible number of errors for the pixel error classII
in accordance with ISO 13406-2
Type 1
Type
2
Type
3
Cluster
fault
(all types)
Cluster fault
Typ 1 & Typ2
15" XGA 1024 x 768
768 432
2
2
4
2
2
17"-19"
SXGA 1280 x
1024
1 310 720
3
3
7
3
3
20.1"
UXGA 1600 x
1200
1 920 000
4
4
10
4
4
14
Sticking image
Image-sticking on LCD monitors
LCD technology has always been known to suffer from certain image retention – Image Sticking, as it has been named. This is
caused by ions polluting the material Liquid Crystal Displays are made of, and thus will occur on all LCD’s. TFT is the name for the
most common used technology in LCD’s.
Image Sticking is a slow build up of energy (ions) in pixels that are statically turned on in a LCD. This energy will eventually keep
the pixel slightly on, and so cause Image Sticking on the display. Image Sticking and the special forms of it “Ghost Image” and
“Boundary Image Retention” is a reversible process, but will in rare cases, where an image has been on a LCD long enough to
physically alter the crystals inside the LCD, be permanent.
ISIC has been one of the forerunners in attempts to reduce Image Sticking through active and
passive measures. Research has shown that keeping the energy-build up from happening is not possible. Removing all DC
components within the driving signal has removed “Ghost Images”, but any bright color displayed on a dark background will still
cause “Boundary Image Retention”.
Caused by ions, being moved around by voltage-levels, Image Sticking will only disappear by
switching the LCD off. A simple rule says that Image Sticking takes approximately as long time to disappear as it takes to be
created. Tests at ISIC have shown that Image Sticking is accelerated by temperature (greater moving activity in the ions).
Freezing the LCD may reduce Image Sticking, as may impose an alternating electrical field across the display. Both these ways of
removing Sticking Image have been deemed unusable in working installations.
