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Technology Behind Plasma Displays
digg writes "CoolTechZone.com has an in-depth article that gives an overview of how Plasma Displays work. From the article: 'So, what exactly is plasma? Plasma by definition is one of the four states of matter (apart from solid, liquid and gas) and consists of positively and negatively charged particles, which are added in roughly the same quantity.' This obviously makes the gas more or less inert but ensures that the charged particles are free to conduct electricity. Plasma can be produced if a gas is energized enough to split the molecules into positive and negatively charged ions. Mostly, the plasma displays use a mixture of noble gases like Neon and Xenon."
Of course, you can get all this (and more) at Wikipedia's Plasma Display page.
;-)
[I realize this is probably karma whoring, but I hate it when there's only one link in summary and it doesn't even have much info, and is littered with ads, and you have to look at 3 pages to get the whole article. That and run on sentences.]
--Xandu
Make that "one of at over a dozen known phases of matter" , not "one of the four phases".
This article mistakes plasma altogether. Plasma is a state of matter in which the electrons are so high in energy that they escape the pull of the nucleus and more or less become free flowing. It is laughable that the poster mentioned that a molecule splits into positive and negative ions upon reaching the state of plasma and then mentions noble gases which do not even form molecules (unless specially prodded). Atoms do become ionized during plasma phase but only because of the displacement of electrons: making all of the ions positive.
Instead of simply vaporizing the poster- we should "plasmatize" him? Maybe he can learn something in the process.
there you go
'So, what exactly is plasma? Plasma by definition is one of the four states of matter (apart from solid, liquid and gas) and consists of positively and negatively charged particles, which are added in roughly the same quantity.' This obviously makes the gas more or less inert but ensures that the charged particles are free to conduct electricity.
"Makes the gas more inert?" Those guys should stick to writing about case mods.
Plasma panels have actually been around since the 1960s, as neon-red displays. The early concept was that a sustaining voltage applied to all pixels kept them lit if they were on, and an X/Y array of wires could be used to turn individual pixels on and off. Thus, the display itself had memory, back when having enough memory to refresh the display was expensive.
Color, intensity variation, and speed took a long time to achieve. Now there are transistor drivers behind every pixel, and the panel is built in what's effectively a big wafer fab. But that's not the toughest part of the manufacturing problem. All the electronics is on the back glass, while the phosphors are on the front. These two big pieces of glass have to be welded together with subpixel precision, held in contact only by millions of tiny ridges that have to match up. That's the most difficult step, and the one that limits display size.
Yeah seriously, its horrible. I mean honestly:
"Each time a different colored cell is charged, this charges the atoms and converts them to ions and facilitates the release of UV photons due to the ionic collision. The inside wall of the cell is meted with a special treatment of a phosphor coating. This is done to exploit the phosphors property of giving out light when it comes in contact with other light."
Ughh, barf, don't even bother to RTFA, not worth it. This is a FAR more fascinating and in depth view into the workings and history of plasma displays.
- "Hear that?! The percolations are imminent! Cease your ingress!"
I have a 50" Samsung 3rd Gen DLP TV ($1600 at Best Buy a few months ago, 0% APR for 2 years). I could not be happier with it. Not only does it have more HD ports than any TV I found in its price range (VGA, DVI, HDMI, 2 x Component), the color and contrast ratio are outstanding (1500:1 claimed) using a 7-segment color wheel (and no, I do not see the rainbow effect, I believe partly die to the higher rotation rate of the 7 segment wheel). Not only that, but it does not suffer from burn-in or fading the way plasma does (important for me for gaming). The only part that needs periodic replacing is the lamp unit itself, which you can find online for around $200, and according to other people with similar sets to mine, each lamp lasts 2-3 years, depending on use. The power savings of DLP over plasma or CRT more than makes up for it, I believe the set I have uses 60-70 W during normal use. In the long run, I don't see plasma sticking around. I see technologies like DLP and LCoS (or D-ILA as JVC calls their version) being the market leaders in 5 years. Plasma always looks over-saturated and grainy to me, not to mention the heat that comes off those things. They might be a little brighter than most DLPs, but I do not believe they are worth it. The only plus side is their depth, 4" versus 14" or so for my DLP.
today is spelling optional day.
The OLED situation isn't quite THAT rosy, but it is promising. OLED lifetimes are lower than plasma right now, although it is getting better. And that whole "roll up the screen" business is a bad idea for anything you want to survive long-term, because any sealing problems that let in water will destroy the organics in the screen. I don't think you'll actually see large screen OLED displays on the market until 2008 or 2009. In the meantime, I bought a plasma.
We don't have a state-run media we have a media-run state.
Personally, I got more useful understanding out of this article at howstuffworks:a y.htm
http://electronics.howstuffworks.com/plasma-displ
-- Given enough time and money, Microsoft will eventualy invent UNIX.
To pedantically correct the original poster, there are *at least* six states of matter, possibly more.
1) Solid
2) Liquid
3) Gas
4) Plasma
5) Bose-Einstein condensate
6) Fermionic condensate
I now take my Physics-pedant hat off and apologise.
Check out the following:
Plasma Cosmology
Plasma Universe
Guided Tour of the Plasma Universe
Electric Currents and Transmission Lines in Space
Immense Flows of Charged Particles Discovered Between the Stars
Interesting quote from Hubble regarding redshift:
Thuderbolts.info
Thunderbolts' Picture of the Day
Picture of the Day Archive
A few very interesting selections from the archive:
The Picture that Won't Go Away
Quasars in Infrared are Still Nearby
Predictions on "Deep Impact"
Electric Stars
Of Pith Balls and Plasma
Space Shuttle Struck by Megalightning?
The website of Halton Arp
The Observational Impet
IC XC NIKA
They were/are called "Field Emission Displays" (FED), if I recall correctly. The idea was to take a flat plate of glass (or equivalent) with normal CRT phosphors, but behind each phosphor put multiple tiny solid-state electron emitters. In other words, instead of taking a single electron beam and sweeping it repeatedly across the screen, put multiple weak electron beams behind each subpixel. The rationale for using multiple beams was avoidance of dead pixels. If there were, say, six emitters behind each subpixel, one or two of them could fail outright or progressively, and the viewer would likely never notice the difference... and the few that WERE bad enough to be noticeable could be programmed around by simply increasing the intensity of that specific subpixel.
I first found out about FED displays (yeah, I know "FED Display" is redundant) when I went to CES in Orlando in 1996(?). I thought for sure FED would rule the day (not for laptops, of course, because they used too much power... but for home TVs). I'm not really sure whether the concept proved to be unfeasible, or whether FED actually mutated something else. My guess is that cheap, hi-res DLP, far bigger and cheaper TFT panels than anyone dared to predict a decade ago, and cheaper & less-fragile plasma all chipped away at the manufacturers' motives for funding it, and they all went after one or more of the other technologies instead.
IMHO, it's a pity. DLP has good intensity, is indestructable, and high resolution, but suffers from either rainbows or high cost & convergence problems. TFT has high resolution, but is limited in brightness when used with projectors, and both size & pixel-perfection in direct displays. Brand new plasma sets look impressive, but they're the lowest-rez sets of all, and I'd personally rather watch a 34" CRT than endure ugly stretched images necessitated by plasma's vulnerability to burn-in due to pillarboxing instead. CRT... well, CRT has probably the best overall color saturation, but is size-limited by the tube itself (unless, of course, your living room is big enough to drive a forklift in).
Sigh. I really, REALLY like the concept of FED displays... they have/had the potential to give us the best features from all the other alternatives (though possibly at a staggering cost).