Technofile: The news that LG Electronic's 50-inch TV set, with the world's first built-in hard disk, received a design award at the CeBIT technology exhibition, shows that flat-screen TVs are taking off. But if you are considering getting an LCD TV or plasma-screen TV, the choice can be bewildering.
Plasma screens first entered the market at the end of 1999, but the concept has been around since 1964.
Plasma display devices have higher resolution than most conventional TV sets and are capable of displaying full high-definition TV and digital TV signals as well as signals from a computer.
Unlike a normal television, which uses an electron beam to scan the picture tube from top to bottom at regular intervals, plasma screens have no scan lines as every pixel cell has its own transistor electrode. This creates a smooth, evenly lit image across the display. A lot of plasma TVs also include built-in line doubling to improve image quality from low-resolution video signals. In fact, high-end plasma displays are capable of displaying 16.77 million colours.
Plasmas have a widescreen 16:9 aspect ratio - the relationship between the screen's width and height. This is the best aspect ratio for DVD viewing. All plasma screens can show the image in its original 4:3 format with bars (either black or gray) on the sides of the image. Plasma and LCD TVs have screens that are perfectly flat, with no curvature like a normal cathode ray tube TV.
These screens illuminate all pixels evenly across the screen, unlike some rear- and front-projection televisions that suffer from uneven screen brightness. Plasma and LCD TVs are often only a few inches in depth, so you can hang them over the fireplace should you so wish. Plasma displays in particular offer a viewing angle of 160 degrees (top to bottom and left to right), which is much better than rear-projection TVs and LCD displays. That way the whole family can view the show.
Should you pay the extra and buy a HDTV plasma television? HDTV (high definition TV) has yet to really hit Europe, but it's about two years away.
If you buy a non-HDTV now, just remember that to partake in HDTV in the future will mean buying a new screen. But normal TV will be broadcast for some time to come, so there's no need to panic. All plasma screens are considered HDTV compatible in that they will convert the signal and display it.
Obviously, you can buy a plasma or LCD TV online but we're going to break with tradition for a technology column and recommend you look in a normal shop. This is because they are almost always authorised and, therefore, the manufacturers warranty will be intact. If the set has a problem, they are often easier to return the set to. But most of all, you can actually view the display that you are thinking of purchasing. The downsides are that prices tend not to be as competitive as online, and they tend to side with one manufacturer over another based on commissions.
But how about LCD TV?
You will tend to find that flat-panel displays like LCDs and plasmas are significantly brighter and feature higher contrasts than traditional CRT sets. A brightly lit room won't wash out its picture, nor will lamplight. One thing to look for in LCDs regards "dot pitch", or how close the "dots" are to one another. The closer they are, the sharper the resolution will be.
Although plasma displays are said to have wider viewing angles, LCD screens have been catching up lately. The advantage of LCD TVs over plasma screen is that they generally come with tuners and speakers already built in.
Like plasma screens, LCDs do not have those annoying scan lines on conventional sets. Although dead pixels will emerge over time, in general the number of dead pixels affecting a given display will be few enough so as to go virtually unnoticed.
Also, LCDs are getting better at displaying fast-moving images. Response time is measured in milliseconds (ms), with the best LCD monitors clocking in with response times under 20ms. Slower response times can cause the image to lag and appear jerky, known as "streaking" or "trailing".
The lifespan of an LCD display is generally longer than that of similar-sized plasma displays. Some manufacturers claim that their LCDs can last upwards of 80,000 hours when used continuously under controlled conditions. Just how realistic such claims are is debatable - and the debate will probably go on forever.
