TFT Technology - Active Home

TFTs are certainly thin and convenient, but they still struggle to match the sheer image quality of the CRT.

A traditional analogue CRT monitor will probably have excellent contrast, unrestricted viewing angles and near instantaneous response times.

Although various technologies have been developed to address these issues and improvements are being made all the time, TFTs can’t yet compete with CRTs in all of these areas.

Each current TFT technology has strengths and weaknesses and the type that’s right for you will depend as much on its intended use as on your budget.

TN panels
Most current 17in panels are of the TN (Twisted Nematic) type.

Although this is one of the oldest TFT technologies it’s still very popular due to its lower cost and ability to deliver the fast pixel response times beloved of modern gamers.

In fact, many modern displays are marketed on response time alone - but beware of the disadvantages of the technology.

TN panels have relatively poor viewing angles - 130 and 140 degree specifications are not uncommon although they have been recently improved upon using ‘TN+film’ technology, where a layer of special film is added.

Vertical viewing angles are especially bad. Looking at even a modern TN panel from above or below can result in huge colour shifts and even colour inversions.

Furthermore, TN panels use 18-bit colour and often deliver less saturated colours making them less suitable for applications such as photo editing and multimedia.

MVA panels
MVA or Multi-domain Vertical Alignment panels were developed by Fujitsu from the older VA technology and now many other manufacturers are also building MVA panels using this technique.

MVA panels and their derivates can achieve much deeper blacks (and hence better contrast ratios) than TN panels with wider viewing angles and superior 24-bit colour rendering with up to 16.7million colours. However, their cost is often considerably higher.

Originally suffering from slower response times, MVA panels can now approach the reaction times of some TN displays thanks to ‘overdrive’ technologies which apply greater than normal voltages to the liquid crystals in a controlled fashion to get them quickly to a state from which they can transition faster to the desired level.

This helps with certain colour transitions but not others and some users claim to be able to notice the introduction of unwanted noise into moving images.

HP’s f2105 MVA-based monitor, for example, produces excellent viewing angles and contrast but exhibits less smooth colours than competitors with IPS panels.

IPS panels
The most expensive panels are currently based on IPS (In-plane switching) technology.

Originally developed by Hitachi, they can achieve very wide viewing angles and excellent colour rendition. More recent S-IPS (Super IPS) panels achieve similar quality but at a much reduced cost.

For critical colour-based work, S-IPS panels offer the best quality alternative to a CRT but they are not without disadvantages: Their internal design means slightly less of the viewable area is given over to actually producing light, sometimes resulting in reduced brightness.

Black levels can also suffer a little when viewed at wider angles.

See also: