Breakthrough In LED Construction Increases Efficiency By 57 Percent

Zothecula writes: With LEDs being the preferred long-lasting, low-energy method for replacing less efficient forms of lighting, their uptake has dramatically increased over the past few years. However, despite their luminous outputs having increased steadily over that time, they still fall behind more conventional forms of lighting in terms of brightness. Researchers at Princeton University claim to have come up with a way to change all that by using nanotechnology to increase the output of organic LEDs by 57 percent.

Comments

The diode itself is unchanged

[i kan reed]

All they've changed is how they contain it to limit the amount of light lose to absorption. I mean, to the user of LEDs the distinction is pretty irrelevant, but if you were wondering how you could improve on such a fundamental electrical component, that's how.

The 57% in the title is misleading.

[Steve Newall]

The article explains that the light extraction is increased from 3% to 60%. This is a factor of 20 increase in light output. So compared to a "normal" LED, this new technology is actually 2000% more efficient.

Re:The 57% in the title is misleading.

[tomhath]

The 57% improvement was on top of existing improvements like adding a reflector. This brought it up from something like 38% to 60%.

Re:You know what this means

[Jim3535]

There is a company that makes lightdims, which are like tinting stickers that you can put over LEDs to dim them (block some of the light). They come in different strengths, even blackout.

I use them on the computers and other electronics in my bedroom since the LEDs collectively put out so much light it's hard to sleep.

The industry will screw you anyway...

[MindPrison]

...because it doesn't pay very well to sell you something that'll last forever, whether it's an Oled screen or LED bulb.

It's no coincidence that the CFLs die off after 1-2 years albeit they're supposed to last 10-20 years with normal usage. My first Philips 11w CFLs that I bought 20 years ago, still glows like mad and simply refuse to die. That is back when the CFLs was new, and cost like 40 bucks just for ONE bulb, but hey...it's actually worth the money, it still is my best bulb.

With LED's, it's a walk in the park for the industry to make them last less, all you need to do for your LED to last less than specified, is to OVERDRIVE them just a little, a little higher current and the LED's will die rapidly, they should be able to make the new LED lamps last just out the warranty period (that in most countries AFAIK is around 3-6 months), or cheap enough to avoid the warranty altogether.

There is nothing wrong with the LED's themselves, (we're talking the components...DIODES...not the whole circuit with drivers and all), I ordered strong RGB leds from China many MANY years ago, they're still glowing on my homemade alarm-systems so strong that I can use them as night-lights, yes...4 years later 24H day use...they still glow enough to lit up an entire room. And I just used Ohms law + 1% resistor values to calculate the right resistor value for my circuits. You can pretty much BET the manufacturers will "miscalculate" these values, or make the drivers for the stronger LED's last MUCH less in order to keep pumping out new ones for the consumers to waste and waste.

I'd rather pay a proper price for my LED lamps - and keep our environment safe from this mad overproduction that now has escalated totally out of hands. :(

Re:The industry will screw you anyway...

[smellsofbikes]

...because it doesn't pay very well to sell you something that'll last forever, whether it's an Oled screen or LED bulb.

With LED's, it's a walk in the park for the industry to make them last less, all you need to do for your LED to last less than specified, is to OVERDRIVE them just a little, a little higher current and the LED's will die rapidly, they should be able to make the new LED lamps last just out the warranty period (that in most countries AFAIK is around 3-6 months), or cheap enough to avoid the warranty altogether.

There is nothing wrong with the LED's themselves, (we're talking the components...DIODES...not the whole circuit with drivers and all), I ordered strong RGB leds from China many MANY years ago, they're still glowing on my homemade alarm-systems so strong that I can use them as night-lights, yes...4 years later 24H day use...they still glow enough to lit up an entire room. And I just used Ohms law + 1% resistor values to calculate the right resistor value for my circuits. You can pretty much BET the manufacturers will "miscalculate" these values, or make the drivers for the stronger LED's last MUCH less in order to keep pumping out new ones for the consumers to waste and waste.

I'd rather pay a proper price for my LED lamps - and keep our environment safe from this mad overproduction that now has escalated totally out of hands. :(

Buy Crees. I work in LED driver design, and Cree, who I don't work for but I work with, seem to do a good job of making sure their LED's don't get associated with junk. Philips similarly, to a lesser extent.
So, from the inside, it's not that manufacturers generally scrimp on bulbs to make them fail faster so they can sell more. The economics of light bulbs don't support that business model. It's that people are crazy reluctant to pay $15 for a lightbulb when an incandescent costs under $1. So manufacturers engage in heavy-duty Muntzing until the bulb will just barely run, and they've cut the BOM by $1.45... and then it dies quickly. It's called value engineering, which as far as I'm concerned means removing all the value. They use cheap input filter caps, and scrimp on those, and they use cheap heatsinking which is poorly thermally coupled to the LED's, so the LED's operate at a high junction temperature and don't live very long.
Incandescents have visual inertia, for lack of a better term: if you pour a 30 hz square wave into one, it'll still look pretty good. LED's react in nanoseconds. Crappy dirty line power combined with dimming makes for a really demanding design, and designers and apps engineers have to work with a huge variation in dimmer designs. Consumers don't see any of that: all they see is "no way I'm paying $25 for a lightbulb" so they buy the crap ones and then get infuriated with them because they're visibly flickering and only last five times as long as an incandescent. I can't really blame them, either. There are really good lightbulbs out there. They're expensive. They should last 50,000 hours. But it's hard to tell what you're getting if you're not in on the design.

Re:You know what this means

[tlhIngan]

Why the hell did the industry move away from using red LEDs for power indicators?

Because people wanted to be "trendy" and "futuristic" and thus started putting blue LEDs (which only came out two decades ago) in their equipment. Red was dull and boring (being done way back in the 60s) as was yellow. Green as we know it today (rather than a sickly yellow-puke-green) was a mid-90's invention. Blue LEDs came out in the mid-late 90s.

So since they were so recent and popular, people stuck them on everything to show they were progressive.

Re:You know what this means

[Dogtanian]

I wouldn't be surprised if blue at night were murderous if our eyes are indeed compenssting by adjusting towards higher blue sensitivity near dawn or dusk when there's not much blue in the incident light.

If you came to that conclusion on your own, I'd congratulate you on (possibly) being extremely perceptive, but also surprised that you weren't aware that it's already been widely reported in the past few years that, yes, blue light is apparently very bad news from the point of view of being sleep-inhibiting:-

Example story

Blue light presumably being far more of an issue in recent years due to (a) the increase in use of electronics and (b) the blue LED fad. (*)

I've seen an alarm clock with blue numbers- presumably because blue LEDs are cool!!!!!!11111- which struck me as an absolutely horrible idea. As did a ******* blue-coloured baby nightlight (because even baby deserves to be kept awake by fashionable blue LEDs. Sheesh.)

(*) FWIW, the blue LED fad seems to have died down in the past couple of years, and white LEDs are the new hotness. Which is a good thing from an aesthetic point of view (**) but I suspect those white LEDs still contain a lot of blue. Especially the more bluish-white ones which may well just be blue ones with phosphor coating (as some "white" LEDs apparently are).

(**) Nothing against blue LEDs as a concept, it's great that they were invented. What I hate is their gratuitous use- or rather, misuse- in consumer goods, both because they're overused and the novelty wore off long ago, but also because they're far more distracting in context than red ones ever were.