Are Nanotube Monitors In Your Future?

cmburns69 writes "There is an article over on CNET News about some new nanotube technology which could replace LCD flat panel displays. "These 'field effect displays,' or FEDs, will consume less energy than plasma or liquid crystal display (LCD) TVs, deliver a better picture and even cost less.". The article is mostly focused on the FED technology, but also includes a summary of what other new display technology is coming up such as SEDs and slim CRTs. "

Comments

for the lazy: the ghosting question

[dAzED1]

From the article, the answer to what these look like from the side: The images produced by CRT tubes are crisper and aren't subject to the shifting and ghosting of LCD screens. However, the electron gun in CRTs requires a large vacuum: the tube in a 30-inch diagonal television is 23-inches deep, though slim CRTs coming next year will only need 16-inch deep tubes.

Like an LCD, an FED is made up of layers. A layer of glass is coated with a cathode and a layer of diamond dust coated with lithium or carbon nanotubes. The negatively charged cathode, organized in a grid, then emits electrons through the diamonds or nanotubes, which focus that energy like a tiny lightening rod.

But then, like a CRT, the electrons shoot through a vacuum at a layer of phosphorescent glass covered with pixels. The big difference is that the source of electrons, the carbon, is located only 1 millimeter to 2 millimeters rather than nearly 2 feet from the target glass, and instead of one electron source--the electron gun--there are thousands. The electrons are attracted to the pixilated glass because this layer contains a positively charged anode.

"This generates light the same way a CRT tube does," said Pitstick, leading to similar picture quality. At the same time, a FED is only slightly thicker than an LCD panel.

Re:Drugged up Diamands

[Anonymous Coward]

Doping means to apply a chemical treatment. So in this case the diamonds are coated with a chemical to change the diamonds' material properties in some way.

Re:Drugged up Diamands

[Twanfox]

No, what they refer to is infusing/treating pure diamond dust with a particular element/chemical.

See: Dictionary.Com's definition of Doped, entry 4 (Electronics)

Still is pretty funny, though.

Re:Drugged up Diamands

[slackerboy]

is developing a similar panel that relies on specially doped diamond dust.

Do you suppose the author meant dropped? Otherwise, I hope that dust has glaucoma!

I suspect the author really meant "doped", as in adding an artificial impurity to create a semiconductor. (It might sell well either way, however...)

But Do they Beat OLEDS?

[ghutchis]

The article is interesting and IMHO, new display technologies will always find their niche. But I've always thought the "next-gen" technology to beat LCD flat-screen or plasma displays was going to be OLEDs.

On the one hand, OLEDs still have some problems with lifetimes--even research devices that I saw in grad school might degrade quickly. And of course I haven't seen anyone really give proof that single-walled nanotubes (SWNT) used in these FEDs can be produced cost-effectively.

However, unlike these technologies, OLEDs have already been produced as prototypes in sizes as large as 40" (by Seiko Epson) and being used in products like Digital Cameras and MP3/Ogg players and being mass-produced by companies like Sony.

Previous Slashdot stories on OLEDs:
http://slashdot.org/article.pl?sid=02/10/15/201723 7
http://slashdot.org/articles/03/03/04/0127213.shtm l?tid=137
http://science.slashdot.org/science/04/03/09/01122 34.shtml
http://slashdot.org/articles/04/05/05/004227.shtml ?tid=137&tid=141&tid=159&tid=184&tid=186&tid=188

Re:But Do they Beat OLEDS?

[Elledan]

The problem with OLED is that it's a technology which is basically being developed from scratch. Variants on OLED are even being developed, to circumvent (among other things) the longevity issues with especially the blue component of OLED (10,000 to 20,000 hours so far).

The thing is that SED and FED are pretty much evolved versions of the venerable CRT: they've got 'electron guns', a vacuum, and a layer build up out of phosphors. Only big differences are the number of electron guns (tens of thousands instead of three) and the distance between the electron guns and the phosphor layer (millimeters instead of tens of centimeters).

SED in particular stands a good chance, as it uses existing manufacturing techniques for the electron gun-layer and further basically replicates a CRT. FED tries to do things a bit fancier, which requires more R&D, and thus more time to bring it to the market.

So in summary, OLED and FED are still (partially) in a research stadium, while SED is ready to be marketed: the first SED displays (TVs) will apppear in 2005, with computer displays appearing in 2006. That's according to Toshiba's PR-department, at least :p

Link to general information on SED: SED

To get the "doped" out of the way...

[flamechocobo]

You guys are thinking of the wrong doped. "Doped" in electronics means treated with a special dopant, which does NOT get you high. Instead, the dopant alters its conductive properties.

Bad choice of acronyms

[awtbfb]

FED has already been used for flat panel screens. Specifically: field emission displays. Worth noting is that these, while very neat, turned out to be fiscally problematic (hence the need for the Wayback Machine). Not a good omen for this incarnation...

Re:In essence, isn't this another type of OLED?

[Anonymous Coward]

In one sense, I think you are right in saying that they are organic. However, FED does not stand for field emitting diode, but rather field effect display (according to the article).

In any case, I believe the term field emitting diode only exists in very specialized situations. I feel that either all diodes emit fields, or none of them do, but I'm only an undergrad, so what do I know? Googling the term "Field emitting diode" will net you 4 incomprehensible results, so I suppose you can make of that what you will. Anyway, my point is that FED shares nothing with the acronym LED.

Carbon Nanotubes

[Anonymous Coward]

What can't they do?

Re:In essence, isn't this another type of OLED?

[reverseengineer]

It can be a pretty hazy definition, but generally pure carbon structures like nanotubes, fullerenes, diamonds, and graphite are considered to be inorganic. The presence of carbon in a compound is a necessary but not sufficient condition for "organicity," as a number of compounds which contain carbon, like carbon dioxide, carbon disulfide, calcium carbonate, and potassium cyanide, are not considered by most chemists to be organic compounds.

Perhaps the best definition that I could give for an organic compound is that it contains carbon in a reduced state. Generally (and almost always for compounds found in nature), that means at least one carbon in the compound is bonded to hydrogen. When plants carry out photosynthesis, they take an inorganic compound, CO2, and use a complex series of reactions catalyzed by enzymes to incorporate it into an organic molecule, glucose (C6H12O6). In the net balance, oxygens are pulled off of carbon dioxide (to our great benefit) and hydrogens are added on. The electronic properties of carbon atoms are altered in a way that makes them "organic."

Now, there are some places where this definition can get fuzzy, and they include the carbon allotropes like diamond and graphite. You can think of a carbon nanotube as a tessellation of fused benzene rings (in fact, some of the companies that make nanotubes use benzene as the starting material). However, benzene is organic (C6H6), and so are naphthalene (2 fused benzene rings, C10H8), anthracene, etc. As more and more rings are fused, though, the proportion of carbon to hydrogen increases greatly until the compound essentially consists exclusively of carbon bonded to carbon, which is an inorganic bond. No need to have your ignorance excused, though- as I said, it's a hazy definition, and the unfortunately terminology of "organic and inorganic" comes down to us from the days when people thought "organic" compounds possessed a sort of vital force that inorganic ones did not.

As for the point about LEDs, I don't know nearly as much in that area, but as the AC who responded to you already pointed out, there aren't light-emitting diodes involved here. As I understand it, the idea here is to create electron guns like those found in a CRT on a molecular scale. In the way that a the point on a lightning rod can "bleed off" charge, these nanotubes or diamond dust motes would bleed off electrons into a vacuum, where they'd fly across and excite a phosphor screen. I know that carbon nanotubes and certain doped diamonds can have semiconductor properties; presumably these would be used to control the current that bleeds off each nanoparticle, and consequently what you see on the screen.