Vertical Alignment
The last of our trio of panel technologies
is VA or ‘Vertical Alignment’. There are two types of VA panels, PVA (Patterned
Vertical Alignment) and MVA (Multidomain Vertical Alignment). PVA is more
common, but both share the same basic characteristics and give similar image
quality. For the most part, VA panels fall halfway between TN and IPS
technology. In terms of cost, colour accuracy and pixel response, VA panels
split the difference.
All use S-PVA (super patterned
vertical alignment)
Vertical Alignment. MVA -
Multi-Domain Vertical
That said, VA screens also have a number of
distinct characteristics that set them apart. Most notably, the default
position of the liquid crystals in a VA pixel blocks light from passing
through. The upshot is that VA screens deliver the deepest, inkiest blacks of
any panel type, and the best static contrast ratios. Colour saturation is
another plus point for VA screens, even if outright colour accuracy is a click
or two behind the best IPS screens.
Colour gamut is another VA strong point.
Like IPS technology, VA panels are typically true 8-bit per colour channel.
That means colour dithering isn’t necessary. Overall, VA panels give the most
vibrant, eye-catching image quality of any LCD technology. The richness and
depth of a good VA monitor is spectacular. For that reason, many high-end
HDTVs, including Samsung and Sony sets, use PVA LCD panels. If VA technology
does have a weakness, it’s pixel response. In an attempt to reduce response
times, many VA monitors use a technology known as pixel overdrive. While it can
be effective for speeding up pixel response, it creates problems of its own,
including input Lag and inverse ghosting.
The spiel here involves altering the colour
of a pixel. That requires a change in the voltage applied. The idea behind
overdrive is to either increase or reduce the voltage fed to any given pixel
more acutely than required for the target colour state. This accelerates the
pixel towards the new colour state more rapidly. Before the pixel can overshoot
the target colour, the voltage is norm alised.
OMG, it’s that 3D
Is stereoscopic 3D really the next big
thing?
The prospects for stereoscopic 3D on the
PC presents quite a conundrum. You can analyse the technology ad infinitum,
but that doesn’t get you past the subjective issues and more than most
technologies, the benefits of 3D are terribly subjective.
But a good starting point goes something
like this: Are you the sort of person who went out of their way to watch the
normal 2D version of Avatar at the cinema? Does the very idea of wearing
silly spectacles make you sneer? If so — and we’ve no argument with you -
current stereoscopic technology for the PC Is definitely not your bag.
Even for 3D fans, it can be problematic.
Whatever technology you go for, achieving the perfect viewing position Is
difficult, and we’ve yet to experience a3 solution that’s comfortable for
really extended use. But if you’re thinking of going 3D, what are your
options?
The most obvious and established platform
is Nvidia’s 3D Vision. It’s proven, It works and its main advantage Es that
It requires relatively little from your display. All It has to do is deliver
a 120Hz refresh. Admittedly, that rules out most current screens, but it’s
easy to imagine 120Hz becoming the norm soon enough. It’s also worth noting
that the high refresh isn’t just a boon for 3D. It makes everything notably
smoother. We’d happily pay extra just for that.
Of course, the downside to 3D Vision is
that is requires both relatively expensive active shutter glasses and an
Nvidia graphics card. It doesn’t work with AMD boards. The alternative Is the
TriDef platform. It works with both AMD and Nvidia hardware and also offers
pretty broad game compatibility. Strictly speaking, It’s just a software
package. You’ll need a TriDef compatible screen and some polarising glasses,
too.
As for which is better, in our
experience. Nvidia’s active shutter tech Is clumsier, but at its best gives
superior image quality than TriDef’s polarising techniques.
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Jargon explained
Grey to grey pixel response Two monitors
both claim 5ms pixel response. They must have the same performance, right?
Nope. There’s more than one way to measure pixel response. The best way is
the full on-to-off state, but many makers quote the shorter time taken to
change between two arbitrarily chosen but much closer colour states, as big
numbers are deemed as bad.
