Pasted from http://www.racesimcentral.net/
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Continuing research on its VA system led to a refinement - which Fujitsu
refer to as Multi-domain Vertical Alignment (MVA) technology - a year later.
The conventional mono-domain VA technology uniformly tilts the LC molecules
to display an intermediate grey scale. Because of the uniform alignment of
LC molecules, the brightness changes depending on the viewing angle. When
this type of cell is viewed from the front, the viewer sees only a part of
the light that entered the LC cell because the birefringence effect of the
tilted LC molecules is only partial for viewers from the front. If a cell in
this state is observed in the direction of the tilt, the birefringence
effect disappears and the area appears dark. On the other hand, if the cell
is observed in the direction normal to the tilt, the birefringence effect by
the LC molecules reaches the maximum, producing a high brightness.
MVA solves this problem by causing the LC molecules to angle in more than
one direction within a single cell. This is done by dividing the cell into
two or more regions - called domains - and by using protrusions on the glass
surfaces to pretilt the molecules in the desired direction. By combining
areas of molecules oriented in one direction with areas of molecules
oriented in the opposite direction, and by making the areas very small, the
brightness of the cells can be made to appear uniform over a wide range of
viewing angles.
It transpires that at least four domains are needed to balance
characteristics such as the contrast ratio, chromaticity, and brightness
over different angles, and the viewing angle of four-domain MVA-LCDs is 160o
or more, both vertically and horizontally. When they were first introduced
in late 1997 they were capable of a maximum contrast ratio of 300:1.
Improvements in light leakage subsequently improved this to 500:1.
Brightness values were similarly improved from 200 cd/m2 to 250cd/m2.
Response times are as fast as 25ms, the rise time being 15ms and the decay
time 10 ms or less. The 10ms response from white to black - which is the
most recognisable transition to human eyes - is particularly fast, making an
MVA-LCD particularly suitable for reproducing moving images.