TFT Technology

Confused about the different types of TFT monitor? We explain all

Written by Paul Monckton

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.

Tags:

Further reading

Viewsonic VA2012w

Low cost 20in monitor that’s great for DVDs and games   More...

AGM CW-19

One of the cheapest widescreen TFTs around   More...

Fujitsu-Siemens S20-1W

Stylish 20in widescreen monitor with 8ms response time   More...

Related articles

Do you agree?

Advertisement

Job of the week

Search thousands of IT jobs :

Search thousands of IT jobs:

Advanced search

Hiring now on ComputingCareers:

Related IT jobs

Search thousands of IT jobs :

Search thousands of IT jobs:

Advanced search

Advertisement

Watch

04 Jul 2008

5.51 MBPodcast Special: Views from the Valley More...

03 Jul 2008

3.46 MBGreen grid computing, Trojans stop play and location-based services More...

02 Jul 2008

3.2 MBOnline TV, SME security and flexible laptops More...

Poll

EUROPEAN E-COMMERCE

EUROPEAN E-COMMERCE

Are you happy making an online purchase from another European country?

Previous poll results

Newsletter signup

Sign up for our range of FREE newsletters:

Existing User

Newsletter user login:

Enter email address to edit your newsletter preferences

Spotlight

Online pornography

US rebate cheques spent on porn

Economic stimulus package works wonders   More...

Louis Vuitton

UK online fake goods market worth £800m

Legal experts warn of dramatic rise in 'e-fencing'   More...

Advertisement

Fibre-optics

New fibre-optic connections overtake cable

Broadband first-timers choosing fibre where possible   More...

Stars and Stripes

Cyber-crooks celebrate Independence Day

Security firms warn users to take extra care   More...

Advertisement