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Toward Micro-Diode Display Panels?
VernonNemitz asks: "Light-Emitting Diodes (LEDs) have been around for decades, and they come in all colors. Here are the basic principles behind their operation, information on what's currently in production , and other practical info. Now, you would think it obvious that video displays should be made from LEDs, to take on the various competitors. Certainly this has been done on a large scale, and I am not the first to be interested in LED display technology for home viewing. The apparent goal of silicon LEDs these days seems to be tied up with optical communications between circuits, have they forgotten the possibility of making high-resolution display panels?"
"Achieving a good image will require smaller pixels, and now I have a better understanding of what has been holding it up, so would like to share what I found out. Basically, unlike a lot of electronic technology, LEDs are mostly -not- made from silicon. So, while silicon diodes are common, and large arrays of them are also made (for sensors), LEDs are not easy to incorporate into standard integrated-circuit manufacturing. Nevertheless, researchers have been pursuing and steadily making progress toward integrating silicon-based LEDs. Even whole arrays, 'suitable for large two-dimensional areas', of silicon laser LEDs have been made, as far back as three years ago."
I think we're barking up the wrong tree using light-emitting technology for displays. I think that we would be far better off having a very high-res, paper-white display that was 100% reflective. Indeed others have called this "digital paper" and it has become a holy grail of display technologies. However the technology to do this is just about here now. I'd much rather see that kind of display. Give me a reflective, 600 dpi display and then I'll read books on a computer. Light-emitting displays are much harder on my eyes than a magazine or newspaper.
I believe new progress in transparent transistor technology could bring many new display types to reality.
Check out the research done at OSU. I spoke with several of the research students regarding this technology and it looks promising.
One of their goals is to make transparent displays like in minority report a reality.
...But not with Silicon. Silicon LED's may be (relatively) cheap for red and green models, but the blue ones are insanely hard to make, and thus are quite pricy (just look at the DigiKey catalogue). Also, Si LED's are very ineffecient (I don't remember the number, but it's like 20%ish I thought). The next "wave" of things are going to come from OLEDs (Organic Light Emitting Diodes). These are easier and chaper to make for screens and such, and eventually can be made in a "roll to roll" production type deal since these things are "grown." They're already being used in some cell phones, I believe.
A problem with these is that they decay if they're not protected, so currently they use a glass-substrate and a glass coating for some, which can make them bulky. Also, OLEDs have a shorter life span than LCD's, but that's being worked on too. So hark, have patience, OLED screens are coming. Another interesting technology to look into is Light Emitting Quantum Dots... those little suckers are cool, and could also replace LCDs and lights as we know it (from what I remember, they're also quite efficient... I think around 60%).
Are you on crack, or just a troll?
The Planck scale, which is likely to be the energy scale of quantum gravity, is around 10^17 times bigger than the weak scale (where we live).
Gravitational effects won't even come into physics at the LHC (unless large extra dimensions a la Arkani-Hamed et al exist -- and they probably don't).
Quantum gravity has bugger all to do with nanotech, or indeed, anything which is likely to exist in the near future...
Check this out. Highlights (emphasis mine):
The cost of the $13 million, four-year project will be shared among NIST, GE and ECD Ovonics. The program goal is to create a cost-effective system for the mass production of products such as flexible electronic paper displays, portable TV screens the size of posters, embedded sensors, solar powered cells and high-efficiency lighting devices.
It isn't because it can't be done. It is because the Veruca Salt money managers on Wall Street can't tolerate a four year return on investment. GE's stock went down when they announced this.
Life is the leading cause of death in America.
So you need a red, green and blue to make one pixel just like a phospher display, and the circuitry to provide a precise analog current to all three LED chips and every pixel. And you have to avoid crosstalk between pixels.
Still, I use blue LEDs on my front panels a lot as simple indicators. They am kool. :-)
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These devices are a more natural successor to the CRT based systems - excellect contrast and brightness (as good as existing CRTs), flat panel design, lower power consumption (as compared to plasma). The technology is essentially one cathode per pixel.
From IEEE Spectrum, September 2003:
Samsung and Motorola are aggressively pursuing field-emission display technology using nanotubes. Samsung, for example, has already demonstrated a full-color 38-inch field-emission display capable of handling normal video frame rates. What's more, a Japanese government-funded consortium was announced earlier this year to develop similar displays, and Sony Corp. (Tokyo) is developing its own nanotube display technology as well.
I'm sorry, I assumed most readers would use common sense first before posting.
1 Cent, huh? Give me a break. No major tech change like this will ever be funded at a break-even point. No, they will LOSE money to go to this.
Note that I didn't say that the price would ultimately be cheaper - I think it will. But saying that and having become reality are two different things.
For instance, they still haven't solved the blue LED longevity problem - one of many things that need R&D. You know, Research and Development? You think that sort of thing costs NOTHING? Please, give us all a break and do a little research before posting like that.
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Back when the MacII first came out, I realized that it could handle 2GB of ram, so I did some paper napkin calculations to figure out how to go about it... The state of the art for RAM were 1megabit chips, with a rated power consumption of 1watt each. I figured you could camolflage the memory unit as a desk... The entire top of the desk would contain cards of ram chips. One pedestal would be a cooling unit. The other would be a 16kilowatt power supply.
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First, each led must have a wire on it. This limits the led to the size, that a ball will fit on. This is usually about 25 microns. (approx 1 mill)
;)
So now the led must be bigger than that, so now you would have a die, normally around 10 mills, to be nice and bright. Now space them out with say 7 mills in between, and do an array, with perfect dimensions between die, (remember, you have to have a spacing big enough to place the wire down to the pcb, and you will end up with a spacing of around 17 mill centers or so.
So you see, the pitch is rather large, then you add some optics, so you can make the whole thing look good, and a 1024 x 768 to be pretty clear.
Then throw in some optics to change the view, to a smaller pitch, and walla you have the viewing scope used on so many tanks
This has been built for along time, and is VERY expensive.
Why not use persistance of vision? Make your display out of three "arms" at 0, 120, and 240 degrees with one arm each for red, blue, and green.
Space the LEDs at less than 0.5mm or so to minimize the "empty" space between each circular line. You can offset the leds slightly if more room is needed or to help manage heat dissipation.
The three arms spin at 60RPS or so to get a decent refresh rate.
The downsides:
1. The circular display area will bother some folks.
2. The outer LEDs will need much more power than the inner ones because they will have to display more rixels (radial pixels) in the same amount of time at the same brightness as the inner LEDs..
3. A large moving part. (Don't move the TV while it's running.)
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Thanks for all the responses!
I should mention that it has been my understanding (perhaps mistaken) that OLEDs are not actually diodes, but "devices", based on electroluminescent phenomena.
I confess I posted the Question mostly out of curiosity: the technology SEEMS so obvious....
I personally agree that reflective-light display technology is potentially inherently superior. My personal favorite (so far) can be found here.