Plasma and LCD panels may look similar, but the flat screen and thin profile is where the similarities end. Plasma screens, as its name suggests, uses a matrix of tiny gas plasma cells charged by precise electrical voltages to create a picture. LCD screens (liquid crystal display) are in layman's terms sandwiches made up of liquid crystal pushed in the space between two glass plates. Images are created by varying the amount electrical charge applied to the crystals. Each technology has its strengths and weaknesses, as you'll read below.
Is there a difference in picture quality between plasma and LCD screens and normal CRT TVs?
It's not what's happening behind the screen that's important - it's how the screen performs as a television that matters the most. In that regard, both plasma and LCD sets produce excellent pictures, although many home entertainment specialists and gamers still say CRTs produce the best overall images (although the latest plasmas are particularly good, and LCD sets are quickly catching up in terms of quality).
Those same home entertainment specialists will tell you that for basic home theatre-like usage, plasma screens have a slight edge over LCDs. This is because plasma screens can display blacks more accurately than LCDs can, which means better contrast and detail in dark-coloured television or movie scenes. The nature of LCD technology, where a backlight shines through the LCD layer, means it's hard for it to achieve true blacks because there's always some light leakage from between pixels. This is steadily improving with every new generation of LCD, however.
What advantages does plasma have over LCD?
Apart from better contrast due to its ability to show deeper blacks, plasma screens typically have better viewing angles than LCD. Viewing angles are how far you can sit on either side of a screen before the picture's quality is affected. You tend to see some brightness and colour shift when you're on too far of an angle with LCDs, while a plasma's picture remains fairly solid. This is steadily changing, however, with more and more LCDs entering the market with viewing angles equal to or greater than some plasmas. Plasmas can also produce a brighter colour, once again due to light leakage on an LCD affecting its colour saturation.
Plasma pundits will also tell you that some LCD screens have a tendency to blur images, particularly during fast moving scenes in movies or in sports. While that was true for older generation LCD screens, newer models have improved significantly -- so much so that the differences in performance between LCDs and plasmas in this regard is almost negligible (here's a tip -- if you're shopping for LCDs, check the pixel response time, measured in ms. The lower it is, the better the image quality in fast moving scenes).
What advantages does LCD have over plasma?
Apart from being price competitive, LCD has the edge over plasma in several other key areas. LCDs tend to have higher native resolution than plasmas of similar size, which means more pixels on a screen.
LCDs also tend to consume less power than plasma screens, with some estimates ranging that power saving at up to 30 per cent less than plasma. LCDs are also generally lighter than similar sized plasmas, making it easier to move around or wall mount.
LCD pundits also point to the fact that LCDs have a longer lifespan than plasma screens. This was true of earlier plasma models, which would lose half of their brightness after more than 20,000 hours of viewing. Later plasma generations have bumped that up to anything between 30,000 and 60,000 hours. LCDs, on the other hand, are guaranteed for 60,000 hours.
You might have also heard that plasmas suffer from screen burn in, an affliction not as commonly associated with LCDs. Screen burn in occurs when an image is left too long on a screen, resulting in a ghost of that image burned in permanently. Newer plasmas are less susceptible to this thanks to improved technology and features such as screen savers, but burn-in is still a problem. But after a few days of use most burnt-in images will fade -- they are no longer permanent.
Do I need to buy 1080p?
If you're a true high-def junkie who's keen to see every pixel of a high-res 1080i/p image reproduced pixel-by-pixel (providing you have a source that high, of course), then LCDs are seemingly the way to go. However, top-of-the line plasmas will also display 1080p content, so the choice isn't as easy as it once was.
Despite the current HD buzz, there is still very little content available in 1080p -- especially compared to the infinite amount of SD content like TV programs and DVDs. Though buying 1080p now may mean you get some degree of future proofing, you may not be getting the best picture. It's not all about the resolution.