EYE-LCD-1700/2100-HB-BC
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8.2 Advantages of the EYE-LCD Series over other display technologies
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Differences TFT/LCD vs. Plasma
All displays from the EYE-LCD Series are
based on the LCD/TFT technology (“Liquid
Crystal Display“/ “Thin Film Transistor“).
Unlike plasma displays that bear the risk
of irreversible “burn-in”-effects, it is almost
impossible that similar effects happen to
LCDs. But it is possible that temporary “ghost
images” can be seen on a LCD when static
image content is represented for longer
periods. This effect is called “Temporary
Image Retention” (TIR) or in its worst version
“Image Sticking“.
To get a comprehensive understanding of
the “image retention” effect it helps to have a
closer look on the LCD/TFT technology.
8.3 The LCD/TFT Technology of the EYE-LCD Series:
The light for the LCD/TFT technology used for the displays from eyevis comes from several small fluorescent
tubes. These tubes are placed behind several different filter layers and a polarisation filter. In colour LCDs each
individual pixel is divided into three cells, or sub-pixels, which are coloured red, green, and blue, respectively,
by additional filters (pigment filters, dye filters and metal oxide filters). Each sub-pixel can be controlled
independently to yield thousands or millions of possible colours for each pixel. If voltage is connected to a pixel,
its polarisation gets changed. This changes the light-flow and the pixel on the screen gets its colour. To achieve
a harmonic brightness over the entire screen area it is important to provide a balanced distribution of the light
from the tubes. Then again, the light is transmitted through the back polarisation filter which is passable in only
one direction. Single sub-pixels can be activated or deactivated by connecting a small voltage to the thin film
transistor (= TFT) of each of these sub-pixels. This small voltage turns the liquid crystals. This allows transmitting
varying amounts of light through the colour filters and the front polarisation filter. Sub-pixels typically
distinguish 6- or 8-Bit grey levels between completely off and on. If the sub-pixel TFT is not activated no light
will pass the front polarisation filter which has a 90° turned phase compared to the back polarisation filter.
In contrast to the irreversible “burn-in”-effects with static images on plasma screens, LCD/TFT screens are only
affected by temporary image disturbances when they are used in the same way. This temporary image retention
can be eliminated by following the advice given below.
The image retention-effect is caused by a persistence of the displayed image. This persistence is caused by
minimal electric rest voltage
inside the LCD module. Hence the
previously displayed image remains
visible on the next image.
As already mentioned, this image
retention-effect is reversible. The
best advice we can give you is
probably not to let this effect occur
to your display at all. This leaflet
gives you the relevant information
you need to avoid the appearance
of image retention on your LCD/TFT
display.
No “Burn-in”-effects as with plasma displays
Less power consumption
Perfect colour, brightness and contrast
characteristics even in difficult light conditions
Reduced image reflections
Little weight
Longer life-time
)
The LCD/TFT-technology used for the EYE-LCD Series
offers all possibilities to reduce the danger of Image
Retention effects.
