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6
A deeper look into LCDs
A deeper look into LCD's
In order to establish a correct assessment on LCD
monitors, it is important to know the fundamentals
of how an LCD device works.
The following explains the basics of how an LCD
device controls light by observing the
characteristics of Liquid Crystals and other key
components used in the device. The
Liquid Crystal - a unique substance
As its name indicates, a Liquid Crystal has the
characteristics of both a liquid and a crystal
(solid) or can be said to be a combination of both.
The molecules of a Liquid Crystal have an orderly
The Liquid Crystal characteristics used in an LCD device
Liquid Crystal substances have many interesting
characteristics, but the ones used to control light
in an LCD device can be summarized as follows:
1. Liquid Crystal substances consist of long
molecules. Interestingly, these molecules
align orderly in their long directions. When
the molecules come in contact with a so-
called 'alignment film', which has
microscopic grooves, the molecules align
themselves with the grooves. By
'sandwiching' the Liquid Crystal substance
between two alignment films arranged with
their grooves at a 90-degree angle, each
layer of molecules gradually rotates to form
a spiral chain of molecules, so the entire
twist (of molecule layers) is 90 degrees from
film to film.
Liquid crystal
Figure 6-1.
30
Product Information Manual Sony Professional LCD Monitors
Liquid crystal
Molecules
Molecules
with alignment film
conventional TN (Twisted Nematic)-type LCD is
used as an example. By reading through this
section, you should get a good grasp on the
general mechanism of an LCD device to help
build your knowledge and understanding of
current and future devices.
orientation like a solid, while they can also move
around like a liquid. This nature of the Liquid
Crystal is the key to controlling the light that
passes through the LCD device.
2. The orientation of Liquid Crystal molecules
can be changed by applying an electric
field. More specifically, the molecule layers
twisted at 90 degrees can be untwisted by
applying voltage in the vertical direction of
the LCD device. The amount that layers
untwist depends on the voltage applied.
3. Liquid Crystal molecules change the
vibration plane of light to match their own
orientation.
4. Liquid Crystal substances are transparent
and transmit light.
Figure 6-2. Molecule chain twisted
90 degrees by allgnment films
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