Yes. An LCD without a backlight (i.e. reflection mode) takes almost no power to operate. Once you count the backlight power consumption, things become more favorable for the OLEDs.
Could be. The blue OLED was the hardest to produce, and fades quiker over time than the green or red. So as well as getting dimmer over time, OLED screens also develop a colour cast.
Not quite. The blue OLED materials typically have electronic properties (in particular, the LUMO level) that makes electrical connections difficult, but we've had blue materials for quite some time. There tends to be a large voltage drop at the cathode, this means they have to be driven harder (and hotter). Also, the photopic response of the eye is best in the green, so for displays (where blue and green are next to each other) the blue has to be driven even harder to be perceived to be as bright as the green by the eye. This has largely been responsible for the poor lifetimes of the blues.
Why do i get the impression that it's bad at showing shades of blue?
Traditionally the blue OLEDs have been the ones with shorter lifetimes not with poor color purity. I started doing resesarch on OLEDs in 1995 before most people had ven heard about them. But *much* research has been focused on better blue materials and they've made great strides in lifetime.
However, that the Samsung demo image contains no discernable blue is very strange indeed. I have my doubts that it was left out unintentionally.
Yes, of course. That's generally what happens as you leave an ice age.
Few scientists would disagree (myself included) that the average temperature of the earth is increasing, but it is in the milliKelvin/decade range and is not the explanation for the warm winter this year. Sorry, but those are the facts.
To say that humans are the cause of this has not been proven (and begs the question). Rather, the data suggest that we are *precisely* in line with a cycle of ice ages that has been going on for billions of years. Such data comes from examining strata in core samples taken from the ocean floor at various places around the world.
You're entitled to your own opinion, but you're not entitled to your own facts...
He didn't say "obtain," he said "make". When we run out of oil, we'll find out how hard it is to make... we're all out of dinosaurs and don't have a hundred million years to wait besides.
Fortunately for us, both plants AND animals have been dying for hundreds of millions of years since the dinosaurs left us thus completing the cycle and continuing to *make* more "fossil fuels" for us. Sheesh. Why do I need to point out the obvious?
It is widely accepted by geological researchers that we are in the process of leaving the last ice age. This data has been verified by scientific research sponsored by more than one government. The warming trends have all been consistent with what they have been at the ends of previous ice ages. There are always alarmists that have to be up in arms about something. Frankly, I'm tired of hearing about it.
Okay, since you asked. I work for Professor Heeger. He started a company called UNIAX back in 1990 to work on these materials (sorry about the website, it hasn't been updated in a while - not because of me though). DuPont (a *very* large company) purchased us last year. Other big companies working on these things are Philips, Pioneer, Covion (a spinoff of Hoechst AG), AGFA (they use conductive polymers in their photographic film to keep static from building up in their roll to roll processing). I believe that Sony is working on them too, but I'm not sure.
As well, there are smaller companies such as Cambridge Display Technologies (who just got a large, but undisclosed, investment last year) in the UK, and Universal Display Corporation in Princeton, NJ that are doing some very good work as well.
I didn't mention these things in my original post as it seemed too much like namedropping. But remember, you asked.
As someone who works in the field of conjugated (conducting/semiconducting) polymers, I have to say that this is actually very exciting news./.ers tend to cast a cynical eye over scientific breakthroughs that won't turn into actual products by 5 PM tomorrow, but examine this for its scientific value and perhaps you will appreciate it more.
The capabilities of conjugated polymers are expanding at a great rate, perhaps because of the backing that R&D is now getting from some VERY large companies. This is especially true since the founders of the field received the recent Nobel Prize in Chemistry (I'll admit to being biased as one of them is my boss).
The promise of these materials is more that of lighter and cheaper than anything else at this point. That may change in the near future though. It's not that they are better materials that those that are in use now, but rather the fact that they are perhaps a bit easier and cheaper to process, relatively inexpensive to make, and perhaps more suited to particular applications. For example, there are groups working on making emissive displays out of semiconducting polymers. If you can make them on a plastic substrate rather than glass, you have a display that you don't have to worry about breaking when you drop your laptop/handheld/cellphone. Now, if we can make one that is easier to see in the sunlight and gives you longer battery life, those are pluses as well.
As far as the superconductors go, we were sure it would happen someday as one of the primary excitations of these materials is what is called a bipolaron. It's basically a Cooper Pair in a conjugated polymer (Cooper Pairs being that thing that makes ceramic superconductors do their thing). The primary problem was getting the polymers to order, or line up, properly. So now it's been done. Yes, it's at a very cold temperature, but all of the first traditional superconductors were down there pretty far too.
By the way, remember that guy who figured out how to make the laser? He didn't know what to do with it at first either. It didn't take too long before it gave people ideas...
From the article: "...these rolled up sheets of graphite atoms...". Graphite not generally considered to be an atom, one really needs to consider the source.
"You can get flexable polymers that can do this sort of thing, but they are not semiconductors, they are called elecroluminescent polymers."
Electroluminescent polymers most certainly are semiconductors. Look at the band structure for any poly(paraphenylene vinylene) or derivative. You get a semiconducting molecule because of the pi-electron overlap, or conjugation, along the backbone. No crystallinity is required.
Flexible displays were first made a long time ago (look up the June issue of Science from 1995). As the electroluminescent polymers *are* plastic, by using a flexible (PET) substrate to build the display on, the outcome is a flexible display. Most of the current research is to improve the lifetime of the flexible displays and make the move to full color.
This is not the same thing as Seiko/Epson's inkjet printing for displays. Regardless of how you fabricate the display, you still have to drive it somehow. Most polymer LED displays are passively driven at this time. Moving to larger format displays requires moving to actively addressed displays (because of power lost from the voltage drop across larger and larger rows). You can still use your inkjet technology on top of this to build a full color, higher resolution, active matrix display. And no, this stuff will not be vapor. My company, Uniax, was recently purchased by DuPont for just this reason.
What's new about this is more the method of manufacturing than the concept (okay, okay, I work for Uniax). Flexible polymer LEDs have been around since the early 1990s (see the 11 June 1992 issue of Science). The problem in getting flexible displays to market has been solving the issues around packaging as the polymers are sensitive to air and moisture and the low workfunction metals used as cathodes are also reactive. Plastic substrates (such as PET) are generally poor oxygen blockers, and give short device lifetimes, however companies like Dow and DuPont are working on new substrate materials and things are looking more and more promising. What is new about this technique is that it gets away from spincasting (think photoresist?) as a processing technique and allows for multiple materials (colors) to be put down in effectively a single layer (people have proposed multilayer polymer devices to do full color, but I've yet to see this implemented). Also, as the solvents for the polymers are pretty nasty (read dissolves plastic ink cartridges), there is some interesting engineering that goes into the system as a whole. To answer some of ryanw's questions: 1) They're quite bright. They can get *much* brighter than a standard monitor. Check the web page for details. 2) The response (turn on) time is very short (nanoseconds). 3) "How 'well' do they respond to electricity?" Light output is proportional to current. This is generally accepted is good. 4) "Why can't you do this with conventional LED technology?" This is a more controversial question, but basically: a) pick and place inorganic LEDs have about reached their resolution limit (and silicon isn't *that* flexible). b) ease of processing - just squirt it on and you're almost done. c) It's relatively inexpensive (whatever that means). Other questions?
Slashdot Mirror
Can anyone explain that?
Yes. An LCD without a backlight (i.e. reflection mode) takes almost no power to operate. Once you count the backlight power consumption, things become more favorable for the OLEDs.
Could be. The blue OLED was the hardest to produce, and fades quiker over time than the green or red. So as well as getting dimmer over time, OLED screens also develop a colour cast.
Not quite. The blue OLED materials typically have electronic properties (in particular, the LUMO level) that makes electrical connections difficult, but we've had blue materials for quite some time. There tends to be a large voltage drop at the cathode, this means they have to be driven harder (and hotter). Also, the photopic response of the eye is best in the green, so for displays (where blue and green are next to each other) the blue has to be driven even harder to be perceived to be as bright as the green by the eye. This has largely been responsible for the poor lifetimes of the blues.
But they aren't harder to make.
Why do i get the impression that it's bad at showing shades of blue?
Traditionally the blue OLEDs have been the ones with shorter lifetimes not with poor color purity. I started doing resesarch on OLEDs in 1995 before most people had ven heard about them. But *much* research has been focused on better blue materials and they've made great strides in lifetime.
However, that the Samsung demo image contains no discernable blue is very strange indeed. I have my doubts that it was left out unintentionally.
These things have been around for years.
Yes, of course. That's generally what happens as you leave an ice age.
Few scientists would disagree (myself included) that the average temperature of the earth is increasing, but it is in the milliKelvin/decade range and is not the explanation for the warm winter this year. Sorry, but those are the facts.
To say that humans are the cause of this has not been proven (and begs the question). Rather, the data suggest that we are *precisely* in line with a cycle of ice ages that has been going on for billions of years. Such data comes from examining strata in core samples taken from the ocean floor at various places around the world.
You're entitled to your own opinion, but you're not entitled to your own facts...
-Mike-
Fortunately for us, both plants AND animals have been dying for hundreds of millions of years since the dinosaurs left us thus completing the cycle and continuing to *make* more "fossil fuels" for us. Sheesh. Why do I need to point out the obvious?
As well, there are smaller companies such as Cambridge Display Technologies (who just got a large, but undisclosed, investment last year) in the UK, and Universal Display Corporation in Princeton, NJ that are doing some very good work as well.
I didn't mention these things in my original post as it seemed too much like namedropping. But remember, you asked.
The capabilities of conjugated polymers are expanding at a great rate, perhaps because of the backing that R&D is now getting from some VERY large companies. This is especially true since the founders of the field received the recent Nobel Prize in Chemistry (I'll admit to being biased as one of them is my boss).
The promise of these materials is more that of lighter and cheaper than anything else at this point. That may change in the near future though. It's not that they are better materials that those that are in use now, but rather the fact that they are perhaps a bit easier and cheaper to process, relatively inexpensive to make, and perhaps more suited to particular applications. For example, there are groups working on making emissive displays out of semiconducting polymers. If you can make them on a plastic substrate rather than glass, you have a display that you don't have to worry about breaking when you drop your laptop/handheld/cellphone. Now, if we can make one that is easier to see in the sunlight and gives you longer battery life, those are pluses as well.
As far as the superconductors go, we were sure it would happen someday as one of the primary excitations of these materials is what is called a bipolaron. It's basically a Cooper Pair in a conjugated polymer (Cooper Pairs being that thing that makes ceramic superconductors do their thing). The primary problem was getting the polymers to order, or line up, properly. So now it's been done. Yes, it's at a very cold temperature, but all of the first traditional superconductors were down there pretty far too.
By the way, remember that guy who figured out how to make the laser? He didn't know what to do with it at first either. It didn't take too long before it gave people ideas...
-Mike-
Electroluminescent polymers most certainly are semiconductors. Look at the band structure for any poly(paraphenylene vinylene) or derivative. You get a semiconducting molecule because of the pi-electron overlap, or conjugation, along the backbone. No crystallinity is required.
Flexible displays were first made a long time ago (look up the June issue of Science from 1995). As the electroluminescent polymers *are* plastic, by using a flexible (PET) substrate to build the display on, the outcome is a flexible display. Most of the current research is to improve the lifetime of the flexible displays and make the move to full color.
What's new about this is more the method of manufacturing than the concept (okay, okay, I work for Uniax). Flexible polymer LEDs have been around since the early 1990s (see the 11 June 1992 issue of Science). The problem in getting flexible displays to market has been solving the issues around packaging as the polymers are sensitive to air and moisture and the low workfunction metals used as cathodes are also reactive. Plastic substrates (such as PET) are generally poor oxygen blockers, and give short device lifetimes, however companies like Dow and DuPont are working on new substrate materials and things are looking more and more promising. What is new about this technique is that it gets away from spincasting (think photoresist?) as a processing technique and allows for multiple materials (colors) to be put down in effectively a single layer (people have proposed multilayer polymer devices to do full color, but I've yet to see this implemented). Also, as the solvents for the polymers are pretty nasty (read dissolves plastic ink cartridges), there is some interesting engineering that goes into the system as a whole. To answer some of ryanw's questions: 1) They're quite bright. They can get *much* brighter than a standard monitor. Check the web page for details. 2) The response (turn on) time is very short (nanoseconds). 3) "How 'well' do they respond to electricity?" Light output is proportional to current. This is generally accepted is good. 4) "Why can't you do this with conventional LED technology?" This is a more controversial question, but basically: a) pick and place inorganic LEDs have about reached their resolution limit (and silicon isn't *that* flexible). b) ease of processing - just squirt it on and you're almost done. c) It's relatively inexpensive (whatever that means). Other questions?