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RSS feedsThe cathode ray tube has served us long and well and will continue toional CRTs and though still priced at a premium, their cost is gradually coming down. We look at eight leading models. inhabit television sets for some time to come. Its future as the front end for computers, however, is less certain and at some point, probably sooner rather than later, the CRT will be replaced by flat-panel display technology. Those big, heavy, radiation-emitting, toxin-impregnated beasts will join the LP and the analogue mobile phone in the skip of history.
'Why the delay?', you might ask. It's not as if the hardware hasn't made it out of the R&D lab yet - flat-panel displays based on the now dominant thin-film transistor (TFT) technology are fitted to every notebook, and standalone versions for use with PCs have been on sale for a couple of years.
So why, when they don't emit harmful radiation, don't take up much desk space, don't weigh more than a few kilos apiece (you're looking at 20kg on up for a larger CRT) and don't require the liberal use of rather nasty chemicals in their manufacture, don't TFTs already rule the world? The reason is much the same as why we don't all drive around in cars made by Mercedes Benz, wearing watches made by Rolex and handmade English shoes. Yes, the reason is cost.
TFT screens can reasonably be compared to giant silicon chips, which is to say that manufacturing large, defect-free batches of them is very difficult, time-consuming, and expensive. So like chips, not many companies actually make them and those that do are in a position to charge high prices to help recoup their considerable investments. The other consequence of this market structure is that supply tends to be short, which is why, unlike virtually everything else in the computer industry, TFT prices recently rose.
Even so, over the long term, prices are gradually diminishing. Two years ago, monitors like the selection reviewed here would have sold for between £1,500 and £2,000 but now they are down to as little as a VAT-inclusive £557 - for which you can pick up Taxan's CrystalVision 625.
What's more, two years ago, flat-panel displays were a rarity. Now, every major monitor manufacturer is producing them and although not all are affordable enough to qualify for inclusion here, there's a sufficient number to offer a realistic consumer choice. It's early days yet but the increase in momentum is very apparent and the slow demise of the conventional monitor is already under way.
Comparative sizes
One of the greatest attractions of flat-panel displays is their relatively compact size. We'll talk in more detail about picture size and resolution later, but for now, if you're prepared to accept the premise that a 15in TFT screen provides a functionally equivalent viewing experience to a typical 17in CRT monitor, the rest of the comparison goes severely against the CRT.
A typical, short-necked CRT with a 17in screen will fit into a cabinet about 16in deep. Since the standard desk is about 30in front to back, this leaves you with 14in to work in. The monitors reviewed here come in cabinets only a few inches thick and even the full footprint of the stands only averages at around 7 to 8in. Furthermore, they're light enough to be repositioned or picked up and moved by almost anyone, which is very much not the case with CRTs.
Confusingly - some would say misleadingly - CRT screen sizes are quoted as maximums rather than actual picture diagonals; so a 17in tube will actually produce a smaller image, generally between 15.5in and 16in across. Conversely, figures for TFT diagonals are absolutes; so a 15in panel will give you a 15in viewable image diagonal.
TFT screens are also crisper and clearer than even the best CRT, so even though the diagonal is slightly smaller, a 15in TFT is as readable at 1024x768 as a quality 17in CRT monitor. This is why in an either/or comparison, the two sizes can be considered the same, and when we talk about the pros and cons of CRTs, we're mainly thinking about 17in tubes.
All the monitors reviewed here ran at 1024x768 resolution except the Taxan, which had a smaller 12.1in screen than the rest and ran at 800x600.
The next up in size was the Samsung at 13.3in, followed by the Iiyama at 14.1in and the Philips was marginally the largest with a diagonal of 15.1in.
Installation
There's never been too much to setting up a display, whatever type it is. You just connect the power and video cables as directed and switch on. None of the monitors here require a special video card or any fancy cabling, as they are all designed to work with conventional PCs. Nevertheless, there are some things to bear in mind when installing a TFT monitor, particularly concerning the refresh rate.
The refresh rate is the number of times a second a graphics card refreshes the image on a screen. Because of the way they work, CRTs need fairly high refresh rates to prevent the image from flickering - 80 refreshes a second (hertz) or higher being ideal.
This isn't the case with TFTs; they appear totally stable at lower rates, say 60Hz or 75Hz, and you need to make sure that your computer doesn't try and use too high a refresh rate as this could cause damage. Manufacturers set about this in several ways, ranging from a stern warning in the manual to set the refresh rate on your graphics card before installation, to providing a disk with the necessary monitor driver.
Alternatively, some monitors are designed so that Windows will identify it as a default Plug 'n' Play display and set the refresh to 60Hz automatically.
The units on test varied amongst these approaches, with Iiyama, Samsung, Philips and ViewSonic providing setup disks and Taxan, Hansol, Maxdata and ADi not including them. In any event, none proved in any way problematic to install, which is encouraging as we didn't use the Registry update disks where provided but always left it up to Windows 95 to do what it thought best.
New gear's resolution
There is one area where CRTs do have a clear advantage over TFTs and that's with resolution. This is an alien concept where CRTs are concerned - they'll display any resolution up to their rated maximum without any fuss. TFTs, on the other hand, are designed to work at one specific resolution and have to resort to trickery to cope with lower ones, with sometimes variable results.
Things are improving in this respect and none of the monitors tested here either failed to cope with the PC standards of 640x480 (used for straight MS-DOS) and 800x600 (popular for DOS-based games), or resorted to leaving a blank border around the edge, even though all bar the Taxan were rated at 1024x768.
When we tried the lower resolutions with text, we noticed that all the panels made some attempt to smooth text to make it more readable and we were pleasantly surprised at how well they coped with action games. The Windows Desktop never reproduced very well but you wouldn't normally want to see it at less than the full rated resolution anyway, so while you will always get the best results at the top setting, lower resolutions for DOS and games sessions are at least a practical proposition.
Plugs & sockets
One slight difference between conventional and TFT monitors is that the latter sometimes come with external power supplies like the brick supplied with most notebooks. This means a bit more clutter, since you have to find a safe home for it. It also increases the distance you can put between your monitor and the nearest mains wall socket, so whether it's good or bad rather depends on you. The Taxan, ViewSonic and ADi monitors we tested here were the only ones with external power supplies.
Amazingly, we only came across one obviously daft design feature during the testing, which was the Hansol's mains switch. Some joker on its engineering staff had seen fit to put it at the back of the stand, where you can neither see nor reach it easily.
For our money, a detachable video cable is a slight but tangible advantage. If a fault develops in the cable, as can occasionally happen, an integral or 'captive' cable will require the attentions of an engineer to replace it, whereas a detachable cable can be swapped out in a minute. Of the monitors tested, the Samsung, Philips and Hansol units had captive signal cables, but as we've said, this isn't a serious drawback and is more likely to be of concern in a business context, where large numbers of monitors are being purchased at a time.
USB still hasn't taken off as a replacement for PC serial ports but the Philips and ADi displays do offer an internal four-port USB hub as an optional bit of future-proofing. What might be of more interest in the here and now are integral, space-saving speakers, which are included with the Taxan, Samsung and Philips monitors.
A word of caution however - integral speakers in monitors tend to be small and this has a detrimental effect on sound quality that will not set the ears of keen gamers, musicians or general audiophiles alight.
True, the quality varied, with the Taxan sounding the thinnest, the Samsung boasting a little more body and the Philips sitting somewhere in between, but these are speakers aimed at undemanding business audio.
Configuration
Fundamental differences in operation between CRT and TFT-based monitors mean that the latter don't need anything like the array of complex geometry correction controls found on a decent conventional display. In fact, apart from centring and sizing, TFTs don't really need geometry tweaks at all.
Instead, the most important controls deal with matching the TFT's operational characteristics as closely as possible to the video signal from the graphics card. Usually called 'phase' and 'clock', these essential controls get rid of horizontal and vertical bands of fuzziness which can noticeably degrade the image.
The other area where it's useful to have some control is colour balance. If you can change the relative intensities of the red, green and blue elements of the picture, you can compensate for an unwanted tint in the white, or make the screen colours resemble the output of a colour printer more accurately.
All our monitors had clock and phase tuners except the ViewSonic, which lacked a clock control for dealing with horizontal noise in the image. Fortunately, there wasn't any, at least in this instance. All bar the Taxan had some degree of colour correction too, with the most offering a couple of pre-set colour 'temperatures' (redder or bluer than default white), and an RGB-adjustable custom colour channel.
Image quality
A good-quality TFT, properly set up, should provide superlative image quality. Focus should be almost painfully sharp, with plenty of brightness without washing out. There shouldn't be any permanently red, green or blue broken pixels either, though one or two of these are still considered within acceptable manufacturing quality control tolerances.
The other thing to consider is the viewing angle - how far (in degrees of arc) you can depart from the horizontal and vertical centre lines before the picture ceases to be readable. Early TFT screens were rather restricted in this respect, but these days most panels offer a decent enough range of viewing angles in both planes.
We didn't have any problems as far as viewing angles went with just one person viewing the monitor but found that if you were sharing the display with someone else, you did need to keep your heads reasonably close together. Aside from empirical viewing tests, it was clear from the manufacturing data that some panels were better than others in this respect, most notably the Philips (H: 150 degrees, V: 110 degrees) and the Maxdata (H: 140, V: 120), compared with a more typical screen like the ViewSonic's (H: 120, V: 100).
The Taxan was by some way the least expensive of the bunch because of its smaller SVGA resolution screen. Even so, the image wasn't as sharp as it should have been, colours weren't very vivid and the picture seemed to go from washed out to too dark without an optimum brightness/contrast setting in between.
Both the Samsung and the Maxdata Belinea suffered from a slight vertical noise problem which just took the edge off the overall focus and made text a little dark and fuzzy. In neither case did adjusting the controls succeed in removing the effect entirely.
The Iiyama did reasonably well for sharpness and was acceptably although not dazzlingly bright, so the main issue here is whether or not you would be prepared to spend an extra £100 or more to get up to a 15in screen diagonal. The difference it makes in terms of the size and therefore the readability of text and screen objects is noticeable. So if the money's there, you might want to consider the Hansol, which proved to be both bright and ever so slightly crisper than the Iiyama.
The Philips acquitted itself well on all counts with a bright, readable and pretty sharp 15.1in screen to its credit. The fact that it has integrated audio and an option for adding USB might also swing things in its favour for some buyers. If not, the remaining choice lies between the ViewSonic and the ADi.
These both produced excellent image quality on their 15in screens and it was hard to choose between them. The ViewSonic was perhaps not quite as bright as the ADi but this was a minor difference. We can't say the same for the price though - at £921 (approximate street price, including VAT), the ViewSonic was comfortably the most expensive monitor on test, whereas the £833 ADi was rather more in line with what we'd expect for a quality TFT monitor of this size.
After some careful thought, the Best Buy this month goes to the ADi MicroScan 6L, which won out on the strength of its impressive picture quality and generally sound manufacture. The reasonably realistic price also helped decide the matter.
We decided that a Recommended award should go to the Philips Brilliance 151AX, which was almost as good as the ADi in terms of brightness and clarity and which had the potential bonus of integral speakers and a USB hub option. It also costs virtually the same as the ADi MicroScan.
DIGITAL DISPLAYS
Many of the problems with image quality on TFT monitors are the result of PC graphics cards. To put it simply, a graphics card converts digital image data from a PC into an analogue signal that can be displayed on an analogue CRT monitor. TFTs, however, are digital devices and so must reconvert the analogue signal back into digital form before they can use it, which is clearly not the ideal way of going about things.
The extra circuitry accounts for some of the extra cost of TFT displays and is often the explanation behind such problems as colour accuracy and image stability. The solution is a digital graphics card designed to drive TFT displays and these already exist, either as dedicated cards or as combined analogue/digital ones.
Unfortunately, although there are plans in the offing, no single standard exists for digital video. VESA - the industry body responsible for many major standards in the graphics market - has proposed something called Plug & Display but it has also approved an interim standard called DFP, which we are more likely to see on actual products first.
To confuse things further, another industry body called the Digital Display Working Group, which numbers Intel amongst its members, is pushing its own Digital Visual Interface standard, so there's probably some way to go yet before a consensus on digital video emerges.
See also:
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