Though both LCD and plasma displays come in the form of slim flat panel displays, yet from a technology perspective, these two flat panel displays process the image in a totally different manner.

Plasma uses a matrix of tiny gas plasma cells that are charged by precise electrical voltages to emit light and hence to create the picture image. Liquid Crystal Displays (LCD) panels - work by trapping a liquid crystal solution between two sheets of polarized glass. When an electric current is passed through the liquid crystals, they change the polarization of the light passing through them in response to the electric voltage – as a result of which, more or less light is able to pass through the polarized glass on the face of the display.

It is not the scope of this article to go into the actual details of how these different display technologies process the image – after all, what really matters is not what is going behind the screen but rather how these different display technologies perform as a television screen. At the same time, it is worth taking note that it is these same differences that give each of these display technologies, its strengths and weaknesses, and that therefore render one more suitable than the other in certain circumstances.

The list below highlights the most important differences between these two flat panel display technologies:

Size: For the time being, collision between plasma television and LCD TV occur in the 40 to 50 inch screen range. In reality, most LCD TVs top out at around 50 inch; larger screen sizes are also available though choice is still very much limited. This means that for anything larger than 50-inch, a plasma display is your only real option if what you are after is a direct-view TV system. On the other hand, at the smaller end of spectrum, namely 15” to 36” TVs, LCD is the way to go if what you want is something stylish and slim (at under 4-inches in depth).

Price: Here, the playing field is leveling at a fast rate. Up to very recent, plasma was the obvious choice for all screen sizes where collision between these two technologies occurs; this is no longer the case. In general, plasma still leads by a good margin only at the bigger screen sizes – 50-inch and upwards. At the smaller end (up to 44-inch), the price advantage when it comes to plasma vs LCD TV sets, starts to shift more towards LCD TVs.

Overall Picture Performance: Both plasma and the latest TFT-LCD flat panel displays are capable of producing excellent picture quality – with bright, crisp clear images. However, plasma flat panel displays are more suitable for basic home theater usage than LCD. The gas cell structure within a plasma display is such that there is no light leaking between adjacent cells (or pixels). This renders plasma displays capable of displaying deeper blacks – hence more suited to television and movie scenes where lots of dark and light content is shown simultaneously.

In comparison, the nature of LCD technology – where a backlight shines through the LCD layer – means that it is hard for it to achieve true blacks (i.e. true absence of light) as there is always some light leakage from adjacent pixels.

This does not mean that LCD panel s are not suitable as TV screens; today’s LCD TV sets make use of extreme high contrast panels that are capable of displaying very deep blacks, yet the latest plasma TV sets still have a slight edge.

Viewing-angle: What used to be a clear advantage for plasma displays is becoming more and more a non-issue especially with the latest generation of LCD televisions, however...

Do not always assume that viewing angle is no longer an issue when comparing plasma vs lcd TVs. The tendency – in particular with the cheaper LCD TV sets - is that the deterioration in picture quality with off-axis viewing is more accentuated with LCD than with plasma displays.

Image Retention and Burn-in: LCD TVs enjoys a technological advantage; they are not prone to burn-in, and image retention in LCD TVs – referred to as ‘image sticking’, is often completely reversible.

It is important to realize here that while burn-in in plasma displays and image sticking in LCD panels both lead to image retention, yet these are two completely different phenomena.

Burn-in is no longer much of a concern as it used to be with plasma televisions up to the recent past, especially for people with normal TV viewing requirements. Similarly, image sticking with LCD TVs is unlikely to take place under normal home entertainment use.

Viewing Distance: It seems that the pixel size and shape of an LCD panel renders a smoother picture than an equivalently sized plasma panel for the same pixel count.

This means that even if your viewing distance falls within the recommended distance of approximately twice the screen width for an HDTV, if this is less than at least nine feet, most probably you will be better off with an LCD TV.

Life-time: This is a non-issue with either technology. In fact, both plasma and LCD TV sets come with a quoted half-lifetime of around 60,000hrs. Even if this were just 30,000hrs, it would imply more than 14 years of use at 6 hours a day. And this when the average household in the US replaces the TV set every 7 years!

In other words, both plasma and LCD TV sets make use of extremely stable and reliable display technologies. As such, lifetime is more dependent upon manufacturer quality rather than upon display technology.

Response: Plasma TV sets carry an advantage here because even though LCD technology has improved to the extent that this is becoming less of an issue, yet LCD has still some way to go to achieve the same level of pixel response times as phosphor based displays.

Power Requirements: The advantage here goes to LCD panels as these consume less electricity. Estimates show that the use of LCD panels can result in some 30% power savings for the same screen size than plasma display.

Making the Choice

There is a market for both plasma and LCD displays - Plasma gives you a bigger screen for your dollar, deeper blacks, but then LCD do not suffer from burn-in and at the smaller end of the market (less than 40-inch screen size), LCD is your only way forward if you want something slim and stylish.

It is all a question of knowing what are the advantages and limitations of each with respect to your specific needs.

This article is an excerpt from a series of informative guides appearing on Practical-Home-Theater-Guide.COM under the Plasma and LCD TV sections of the site.

It covers only the very basics when it comes to compare plasma vs LCD TVs. There are a lot more considerations one has to take into account when selecting the display technology for a flat screen TV.

To find out more, please refer to the detailed guides appearing on the same site at http://www.practical-home-theater-guide.com/plasma-vs-lcd-TV.html.

Last updated on 10th May 2007. Copyright (c) 2004/2007 www.practical-home-theater-guide.com. All rights reserved.