The luminous output of LEDs has been increasing steadily, but they still fall behind more conventional forms of lighting in terms of brightness. Researchers at Princeton University claim to have come up with a nanotechnology to increase the output of organic LEDs by 57 percent.
This discussion has been archived.
No new comments can be posted.
LEDs Using New Nanotechnology Increases Output by 57%
|
Log In/Create an Account
| Top
| 15 comments
| Search Discussion
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
(Score: 3, Interesting) by anubi on Saturday October 04 2014, @04:17AM
I have been messing around with high power ( 100 watt and up ) LED's a bit.
Some of my stuff had to be water cooled.
I have noted a lot of LED failures, even to LEDS in the hundred-milliwatt range, caused by inadequate heat sinking.
LED's which should have lasted decades, fail within weeks of installation.
Almost every instance I have come across, it was a thermal problem. The remainder was improper driver design.
When I do custom designs for clients whose light source is to run for decades ( think outdoor signage which is hard as hell to get at once placed ), I use arrays of 100 watt LED chips, but only drive them to 10 watts or so. And ( by God ) I do not put the driver in the sign! Those cables individually powering each LED chip array are often my only way of telling whether or not an expensive foray up the pole is called for.
So, my big interest is not only emitting more of the supplied power as light, not as heat, and how tolerant are the new technologies to running hot?
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
(Score: 2) by mth on Saturday October 04 2014, @06:07AM
This new technology is for improving organic LEDs. As far as I know, organic LEDs are used in displays (phone screens etc) and not in LED lighting.
(Score: 3, Insightful) by Techwolf on Saturday October 04 2014, @04:26AM
How long will these last? I found out the hard way that organic LED displays will literally burn in. Thats right, those fancy displays on high end smartphones will burn in an image due to limited lifetime of the LED pixel.
(Score: 0) by Anonymous Coward on Saturday October 04 2014, @08:28AM
So now screensavers have a practical purpose again?
(Score: 2) by acid andy on Saturday October 04 2014, @09:50AM
The candle that burns twice as brightly burns half as long ...or something.
If a cat has kittens, does a rat have rittens, a bat bittens and a mat mittens?
(Score: 0) by Anonymous Coward on Saturday October 04 2014, @11:01AM
I have always been kinda scared when I read the word "organic". Although it sounds like something to eat, it also sounds like something that's perishable. Best kept in the refrigerator - and if you are not careful, bugs get in it.
(Score: 4, Insightful) by kebes on Saturday October 04 2014, @01:30PM
So, organic compounds are not necessarily susceptible to being digested by biological creatures. The materials we use as structural plastics are indeed very robust against biological or even chemical attack. And similarly the organic compounds used in OLEDs are not bio-friendly, and are in fact quite robust.
Having said that, it is well-recognized in chemistry that carbon-based materials are generally softer and more fragile than "inorganic" materials like metals, minerals, and so forth. Organic molecules (carbon-based matter) tend to be more susceptible to UV-damage, thermal damage, and so on. So it is true that OLEDs should (and do!) experience more degradation than inorganic LEDs. But OLEDs have advantages in terms ease of processing and manufacturing, power efficiency, flexibility, etc.
(Score: 1) by anubi on Sunday October 05 2014, @12:34AM
Thanks, Kebes!
That is the best explanation of this I have seen.
With the clarity you can express things, I hope you are a college professor.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
(Score: 2) by kebes on Saturday October 04 2014, @01:17PM
The core LED technology isn't changing; which is an advantage in the sense that this coating can be applied to any LED (in principle). So as LED technology improves, this coating can keep be applied to new devices. Actually, it's possible that this coating will slightly increase the longevity of LEDs, since internal light-absorption (and concomitant heating) is one mechanism by which LEDs can degrade. But I wouldn't expect that to be a huge effect.
(Score: 2) by toygeek on Saturday October 04 2014, @04:47AM
Now my keyboard is going to not just annoy me at night, but potentially blind me if I turn on caps lock for too long!
There is no Sig. Okay, maybe a short one. http://miscdotgeek.com
(Score: 2) by Tork on Saturday October 04 2014, @09:44AM
🏳️🌈 Proud Ally 🏳️🌈
(Score: 2) by Immerman on Saturday October 04 2014, @05:49PM
So you're comparing different lighting technologies and saying one is brighter than the other - you'd better give the constraints of that assumption, because I guarantee you 1,000,000 LEDs can be brighter than one incandescent bulb, and there is no natural 1:1 mapping between "lighting devices".
So are we talking brightness per pound? per Watt? per cubic inch? per Watt of available cooling?
Without more data I have to guess wildly, with the most likely metric being "per device that can be screwed into a random incandescent outlet that may have lousy airflow characteristics", which probably maps to something close to "per Watt of cooling per degree". But then again they're talking about OLEDs, and weren't those supposed to be the ones that would make awesome lighting panels offering a uniform wide-area diffused lighting source? By that metric the problem isn't poor brightness, it's trying to shoehorn new technology into an Edison Screw socket standard designed for technology over a century old.
(Score: 2, Informative) by mathinker on Saturday October 04 2014, @08:53PM
I think he meant luminance [wikipedia.org], which is a physical property of an optical system which doesn't scale linearly as one adds more emitters. (In fact, I don't think it scales at all.)
I am not a physicist, but my impression is that lasers are currently the highest luminance light sources, but they're expensive.
Oh, and the summary is bad --- the article is about OLEDs, which are currently used for displays (where luminance is more important than, for example, indoor lighting).
(Score: 2) by Immerman on Sunday October 05 2014, @04:52PM
I'm pretty sure you're mistaken about luminance not scaling linearly. From the relevant Wikipedia pages
>Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction.
>luminous intensity is a measure of the wavelength-weighted power emitted by a light source in a particular direction per unit solid angle
So luminance intensity is a measure of angular (distance invariant) power density weighted by our ability to actually see it - so 1 watt per steradian of green light will be considerably more intense than 1W/steradian of almost-infrared light, but half as intense as 2W/ster of green light.
Luminance then considers the weighted power being emitted per unit area, rather than from a point source. Basically it's the brightness of a single unit area of illluminated surface, rather than the total amount of light the surface is emitting.
As such luminance intensity is going to be the more relevant measure for lighting purposes - the brightness (luminance) of a piece of paper in a room is going to depend on the total amount of light emitted by the source over the angular area intersecting the paper - aka the luminance intensity. The physical size of the light source (and hence the luminance of its surface) is irrelevant to the brightness of the piece of paper it's illuminating.
*Perceived* luminance does not scale linearly, but that's because our eyes, like our ears, operate on a roughly logarithmic scale rather than linearly. Two 40W bulbs will light a room just as brightly as one 80W bulb, but either way the room will NOT look twice as bright as with only one 40W bulb. You need to increase absolute brightness exponentially in order to increase perceived brightness linearly.
(Score: 0) by Anonymous Coward on Sunday October 05 2014, @01:49AM
Is nanotech the new asbestos? [lowtechmagazine.com]