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Technology Report - Plasma TV Screens - March, 1998

By Colin Miller


Consider this a preview of what may lie ahead, not only in possible product reviews, but technologically. Plasma screens have been around in the corners of the video arena for years, playing roles primarily in public display and corporate situations, but, for one reason or another, haven’t really hit the mainstream video market. As advances in performance and value increase, however, the technology gets closer. From what I’ve seen recently, that arrival seems imminent.

Dining room with plasma screen TV (4605 bytes)I scooted myself around San Francisco on my banged up Suzuki to meet Chris Bright of Insync Communications, and Ken Hunkins of Fujitsu General America, for what I can best describe as a private press conference. Needless to say, like most occasions, I was way underdressed. I arrived in an olive green t-shirt, dirty jeans, and a scuffed up motorcycle jacket, contrasting their more formal attire. Even with my less respectable garb, they offered me a cola, and then set about introducing me to what plasma screens, and particularly their product, the Plasmavision 42EP is all about.

Now, before this comes off a shameless plug, let’s get clear that it’s not a product review. A press conference, even as intimate as this was, doesn’t really allow an unbiased, get to the nitty gritty depth that a review by our staff allows, but it does effectively impart a lot of information that may prove useful in the future. Besides, I got free soda. So, even though this isn’t a formal review, I’ll share the experience anyway.

So what is Plasma Television? Well, aside from being a self-contained, flat (about 6" deep) video monitor, it’s quite interesting. The above photo shows a plasma screen TV tucked into a little nook above the fireplace on the right. The animated graphic below on the left shows how thin the screen is. While tube televisions shoot electrons at a screen, scanning back and forth (30 complete frames divided into alternating lines called fields which refresh 60 times a second), plasma televisions work similarly, but differently (I did say this wasn't a formal review). Fujitsu Plasma Screen (2560 bytes)They’re kind of a cross between a conventional television, an LCD, and a fluorescent light bulb. Like an LCD, each pixel is controlled individually from the sides of the screen. Like a conventional television, the phosphor-coated screen itself is the source of visible light, which allows viewing from all directions. And, like a fluorescent light bulb, ultraviolet light is generated as the electrons in a gas excited by a charge, fall in their energy levels, and the UV light hits the phosphor coating which then releases energy in the form of visible light. In fact, that’s the best way to think of it, a lot of fluorescent light bulbs of different color put into a screen. Plasma Screen Animation (19159 bytes)Each pixel is its own lightbulb, complete with electrodes, gas, and phosphor. Each pixel has three sub-pixels, one sub-pixel each for red, green, and blue. The pixels are capable of displaying 16,000,000 colors. They call it plasma because the gas reaches a plasma state. A plasma state requires that a gas actually reach energy levels high enough that the atomic nuclei part company with their own electrons, as ionic compounds separate in a solution. That would be really hot, which probably explains the presence of cooling fans. You can read more about plasma by clicking here.

In a way, even though most video sources are analog at some point, plasma screens are very digital, as each pixel, or for that matter, each sub-pixel (three different colors, red, green, and blue to a pixel) is individually controlled. LCD panels do this, except that they’re currently very small, not very bright, and like many projection televisions, hard to see from an angle. LCD projectors shooting onto a flat screen designed for broader viewing angles can solve part of the problem, but still require, for the most part, low levels of ambient light, which is fine if for dedicated theater use, but irritating for many occasions. Projection televisions can use dispersion screens to scatter the direction of light, making side viewing possible, but lose brightness at the main viewing position. So, in this respect, plasma technology would seem to dominate.

Because plasma stimulates the screen itself, it provides not only a wide viewing angle (1600) and good brightness levels, but another key advantage. It’s both self-contained and flat. Six inches flat, at least, which is flat enough to put on the fireplace mantle, without a box hanging from your ceiling, or behind your head. I suggested to my future in-laws that they could buy a DVD with a recording of a fireplace or an aquarium and have it do double duty as both a video monitor and a room decoration. Seriously, you can put it just about anywhere, without it taking over the room. This gives it a great Spousal Acceptance Factor.

It does, however, carry some disadvantages of sorts. For instance, because it creates such heat, it uses cooling fans. They’re not all that loud, somewhere in the neighborhood of 45 dB at 1 meter (0 dB being the lower limit of human hearing at 1 kHz), so that if you’re sitting about 12 feet away, your noise floor will be, depending on your environment, no lower than 35 dB (equivalent to many classic concert halls during a pause.) Not a horrible compromise, much quieter than many LCD or 3 gun CRT projectors, but worth noting.

Also, since the screen resolution is 852 pixels wide and 480 pixels high (16x9 aspect ratio), there are a lot of pixels (e.g., x,y coordinates 398,460) which may not take at manufacturing. Since manufacturing QC allows up to three dysfunctional pixels, if you look close enough, it may look like you’ve got a couple specs of dust on your screen. At the same time, once made, pixels do not fail.

A plasma screen has the same phosphors as a regular television, so like a television, it has a brightness half-life of 30,000 hours. But, since vision is logarithmic, it translates into a 3 dB decrease in brightness (not a whole lot) if you left it on 1,250 days straight. If you watched it eight hours a day, you could watch it ten years before it reached it’s half-life, and then you still probably wouldn’t notice a difference unless you did a back-to-back comparison.

These things are expensive too! The current Fujitsu model, the 42EP, retails for $10,999. In context, though, it’s cheaper than the previous model, the 42, at $14,000, with better contrast - 400:1 vs. 70:1. For those interested, there is an upgrade. It involves a complete chassis change and costs $10,999. Plus, you get to keep your old one, or give it to me.

The particular model I saw seemed quite nice. It offered a variety of inputs including composite, S-Video, S-VGA, and RGB component. It also allows different options for the white tint (measured in Kelvins for all you ISF fans). Lastly, the 16x9 aspect ratio can be adjusted to accommodate non-letterbox material, and it will still accommodate HDTV and other DTV formats.

The current screens aren’t all that big when compared to the larger projection televisions such as 10 foot screens. The 42" model is the biggest they make now, but in the future, Fujitsu may make larger ones once the manufacturing facilities become ready. Something around 6' in width would be great!

The picture itself, in a well-lit room, I thought very good. To be fair, I didn’t have anything to compare it to, but the computer generated images were awesome. Reds didn’t bleed, they contained vivid detail, and even way off-axis, it stayed that way. It did reveal imperfections in some DVD material. In "The Arrival" and "Outbreak", the blacks became severely pixelated, for instance, when looking at the back of somebody’s head. It looked like compression artifacts, like a jpg file that had been saved with too few bits. Since the computer images showed no problem, I assume it was either the DVD player (a Toshiba which is supposedly quite good) or more likely, the software.

Oh, I tried to forget, but the Plasmavision 42EP also comes with some internal speakers. The're fine for a small board room demo, but I don’t expect that anyone willing to spend $11,000 on a monitor for home use is actually going to use the internal 3 watt amplifiers and some dinky excuse for full-range drivers. Come on! Plug a 5.1 system into that baby!

All in all, I think the plasma screen is kind of cool, and does things for decorative considerations that other technologies simply can’t. They are expensive right now, but are definitely going to be cheaper and more commonplace in the future because they take up so little room. If you are in a hurry to get a "conversation piece", give Fujitsu a call. Their web site has some plasma screen info.

Colin Miller

Copyright 1998 Secrets of Home Theater & High Fidelity
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