Office Automation

Plasma display terminals : See the big picture

Have you wondered how big a display device can be made? Did you think that a Plasma display terminal was the same as LCD display? You thought Plasma display units have very short life and the gas needs to be refilled frequently? You thought the higher contrast ratio’s were the only advantage of Plasma displays? This article on Plasma displays is for you, then.
Options for Bigger display units:

There are a few options available for viewing multimedia in bigger displays – LCD/DLP Projectors, Rear projection Video Wall Cubes, LCD Monitors and Plasma Display Terminals. Though the production of LCD Monitors have overtaken the Plasma display terminals, if you strictly consider the number of devices sold for both,  these two technologies are totally different from each other and the segment they address is also different. While 42″ and higher LCD monitors are available today, they are not as good as Plasma display terminals at higher sizes. LCD monitors do have a cost advantage as they are manufactured in bulk. And at smaller sizes, they are dominating the market today. The main problem with LCD/DLP display projectors is the lack of support for HDTV format and the overly costly Lamp (which needs to be changed every 2000 hours). But they give decent quality big display in any size you want (Up to 300″ Diagonal but at higher sizes, the images are of lesser quality). And yes, rear projection video walls too can give really big and high-quality images by arranging them together, but the cost of such video wall cubes can be justified for special purpose applications like control rooms or network monitoring stations of large ISP’s etc.     

Plasma display terminals:

That leaves us with Plasma display terminals. You should really see one to appreciate the quality of images they give. They start from around 32″ (Diagonal Screen size) and go up to 150″. But at 29″/32″, the CRT or LCD display monitors might be a better buy.  When you want to 42″ or higher display, Plasma display terminals are a serious consideration. They also come in sizes like 50″, 65″, 103″ etc.

Plasma display terminals have a very high contrast ratio (Don’t go with the manufacturers specifications though – each of them measure Contrast ratio in a different way). There is an ANSI standard, which none of them follow! Technically, they should have a higher brightness, but LCD monitors beat them on a well lit room. But there can be nothing better than a Plasma in darker conditions – their colour reproduction is more life-like with deep richer blacks. And they support a wide colour palette as required by the HDTV standard – but such minute differences, the human mind can never perceive! But when compared to LCD monitors, the colour reproduction is better. What colours you see in your laptop (Which is also LCD display), is not accurate – compare it with the colours of a CRT monitor and you will know why!

Plasma display terminals also support HDTV formats and the 16:9 wide-screen format required for HDTV. Some of them come with anti-reflective screens to reduce in-room reflections, and this could be a boon in moderately lit conditions.

Before some years, the maximum life of Plasma display units were advertised as 10,000 hours, but now they are being advertised as 60,000 hours. This is the time that takes for the Plasma display terminals to come to half of its brightness levels. So, the brightness does reduce as it is used more and more, but if the life is anywhere close to the advertised 60,000 hours, then it should be sufficient for most of the applications. And yes, there is no gas recharge required as long as you own the Plasma display.

Another striking advantage of Plasma terminal is their wide viewing angle. So, you can view it from any angle and the image quality or colours will not suffer. Compare this with LCD displays which have quite a narrow field of vision. Try going sideways and looking at your laptop, to understand this point. But the recent LCD monitors have improved on this. The Plasma display can be mounted both vertically and horizontally – could be useful for certain advertising applications/ displays in malls etc. Plasma display terminals have a faster response times for image display. Especially the super fast images of sports etc.

Plasma display terminals are slim and lighter than the CRT display units, and can be wall mounted too but LCD displays beat them on both counts. Partly because of the lower sizes, and partly because there is a full screen size glass mounted on a plasma display to hold the gasses intact.

Applications:

As you might have guessed, home theatre is a segment that is being targeted for Plasma. Except for the cost, there are no other major dis-advantages in this segment. Digital Signage solutions require Plasma display terminals. Advertising in malls, movie theatres, shopping complexes, hotels etc. could do better with a Plasma display. In the enterprise application, they are mostly seen in the reception or the board rooms. Plasma display terminals are the preferred choice for video conferencing output, as the pictures are more life-size. But with bigger displays, the small errors in receiving the video packets(due to packet drops etc) that might be negligible in smaller monitors could appear noticeable in Plasma. They are also used for making presentations in a small meeting room.

Disadvantages:

As was mentioned earlier, Plasma display terminals are not very clear in brightly lit rooms. Most of the normal accessories like VGA input, DVI Input, HDTV inputs, S-Video/RGB inputs, Speakers etc. might be available only at extra cost – so careful with this one. Screen burn-in (Especially visible with smaller text like spread sheets etc.) might affect a few of them. LCD terminals are much better at displaying text and small characters. Strange though it may sound, they do not come at sizes less than 32″ diagonal! They are heavier than LCD terminals because of the full screen length glass, and if it breaks, it might be harder to replace/repair them. The brightness decreases with usage, so for very heavy usage applications, this may not be suitable. The main disadvantage is the cost of production and cost of buying them. And the fact that they are not manufactured in bulk – when compared with LCD terminals.

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