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These technologies also apply to computers and it's interesting to note that although the TV gave us computer users the cathode ray tube, we've returned the favour with LCD flat-panel displays.

I know that when the issue of display technologies is raised with informed company, opinions as to which is "best" and most sensible vary widely.

Way back in "the good old days", we computer users had cool green screens with high-persistence phosphor that gave them a rich, warm appearance -- even if it did mean that any form of scrolling or other movement produced massive smearing.

The reason for this slow phosphor was that many of these old machines had pretty primitive electronics and refresh rates were nowhere near those of today's. A long-persistence phosphor was the simplest and cheapest solution to the flicker problem so it was widely used.

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Of course early TVs were monochrome too -- albeit not green. They however, used a somewhat faster phosphor so as not to cause that ugly smearing in response to motion.

For many years we made do with one colour (white for TV, green or amber for PCs).

By the early 1980s however, every man and his seeing-eye dog wanted colour, so the color CRT became the norm. Colour CRT technology has changed little from the early days which is a great testament to its performance and reliability.

Despite the arrival of plasma, projection and LCD displays, the majority of TV sets and PCs are still using a good old vacuum tube firing electrons through an etched metal mesh at a grid of phosphor dots.

Many videophiles will tell you that the humble CRT still offers the best contrast, colour fidelity, motion response and overall light output.

Unfortunately the CRT is heavy (as anyone with a computer monitor larger than 17" will confirm) and doesn't always offer 100% accurate geometry. Indeed, a great deal of the electronics and adjustments in a CRT-based display are involved with correcting for things such as pincushion, trapezium, tilt and other non-linearities intrinsic to the technology.

Of course the display de jour is LCD. Flat panel LCDs are now probably outselling CRTs for computer use and you can't walk near a major appliance store without facing a wall of the things.

On the up-side, they're perfectly linear. Straight lines are straight, circles are round and every pixel is where it should be. That's good news for computer use but perhaps somewhat less important for TV.

On the downside, there are a lot of pixels on those panels, each one driven by a tiny transistor. The potential for failure is very high -- and a failed transistor or LCD cell can produce either a black dot (dead pixel) or a hotspot.

Either of these failures can be a real pain. Once you realise that you've got a failed pixel, it'll forever stand out like a sore thumb. Any time there's movement or a camera pan, that black or hot pixel will really catch your eye.

Each manufacturers seems to treat the dead/hot pixel issue differently.

The very best will warrant against dead/hot spots, others will consider a certain number (sometimes a surprisingly high number) of such failures to be acceptable and not covered by warranty.

One of the key things to check therefore, when buying an LCD (or plasma) panel is the way such failures are handled. It's also a good idea to make sure you give the screen a *really* close inspection before accepting it. On a brand new unit you should have *no* dead/hot pixels, regardless of the warranty terms. If you get one that's not perfect, don't accept it -- ask for another.

Of course much of this also applies to plasma displays -- although they're so 2005 now. Never the less, they have their advocates who claim that they don't suffer the same motion-induced artifacts that some LCDs produce.

Quite frankly, given all the issues involved in setting up the ideal TV and home-theatre system, I'm really glad that I don't care that much.

My tired, seven year old bottom-of-the-line Sony 29" set is still working and, when I have absolutely nothing else to do, I sometimes sit in front of it for a few minutes before realising that life's too short to waste.

I'm sure you, and others, have plenty of opinions on the best display technology and the advantages/drawbacks each offers. Share the information...

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