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Hardware German Scientists Awarded Prize for Work in LEDs
Levi Beckerson (Blog) - January 7, 2008 10:14 AM

21 comment(s) - last by mindless1.. on Jan 21 at 10:09 PM

Dr. Stefan Illek and Dr. Klaus Streubel (Source: OSRAM)

More innovation in the LED tech sector debuted in new lighting module.

We've seen LEDs in everything from cars to laptops to TVs. A handful of German scientists recently won the German Future Prize 2007 for their work with LED illumination technology.

Dr. Andreas Bräuer of the Fraunhofer Institute for Applied Optics and Precision Engineering IOF in Jena and Dr. Klaus Streubel and Dr. Stefan Illek of OSRAM Opto Semiconductors received the award for technology and innovation, which is bestowed by the German President. The work is based on previous work by OSRAM in thin-film LEDs which permits the extraction of light in a single half-sphere.

The breakthrough in design allows all colors of the LED to be combined as well as more efficient temperature management. In order to harness the capabilities of the LED, a special optical piece was designed at Fraunhofer. The equipment consists of two lenses, the first of which gathers the emitted light and shapes it into a beam. The second lens homogenizes the light from the first before allow it out into the world.

The technology is already in use in digital projectors and is expected to find its way into other appliances like rear-projections TVs and infrared systems as well as in the new OSTAR Lighting LED. Some 2008 production vehicle headlamps will also use the OSTAR module.

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Bulb

By Master Kenobi

(blog) on 1/7/2008 10:42:56 AM , Rating: 2

I've got a few LED bulbs at home for regular ceiling lights, I rather like them and the heat they don't put out.

RE: Bulb

By GrandMareg on 1/7/2008 11:32:50 AM , Rating: 2

How are they compared to incandescent lightbulbs in terms of that 'natural light' feeling? I've been wondering about these for a while.

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RE: Bulb

By ajfink on 1/7/2008 11:42:35 AM , Rating: 2

I'd like to know as well.

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RE: Bulb

By Master Kenobi

(blog) on 1/7/2008 12:17:06 PM , Rating: 2

They give off a sterile white color. It's not the yellowish that we have been using for years. It took a few days to get used to but I find the pure white light to be easier on the eyes.

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RE: Bulb

By Master Kenobi

(blog) on 1/7/2008 12:19:39 PM , Rating: 3

Just to add, I find that the pure white from the LED's also doesn't blind the shit out of me when I flip them on in a completely dark room. The eyes adjust almost instantly, and you don't get that delay where your eye sight is adjusting like when using "old yeller".

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RE: Bulb

By codeThug on 1/7/2008 10:56:00 PM , Rating: 2

could you lay a manufacturer/product name on us? I'm LED curious.

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RE: Bulb

By MrTeal on 1/7/2008 11:43:27 AM , Rating: 2

Do they exhibit the same problems as the LED Christmas lights? On every tree I've seen with LED minilights I can see them pulsate, and I find it incredibly annoying. Hopefully the ceiling lights don't have the same issues.

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RE: Bulb

By Master Kenobi

(blog) on 1/7/2008 12:16:05 PM , Rating: 2

No they don't pulsate. I've never seen anything other than the LED christmas lights that do that. I have no idea why they do it either.

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RE: Bulb

By voyager2084 on 1/7/2008 1:02:05 PM , Rating: 4

I think it's because in the Christmas lights, the AC input isn't rectified. In general, diodes only let current flow in one direction through them, so they are effectively off for half the time, on for half the time without a rectifier. For proper lighting, this circuit is easy and inexpensive to implement, so they don't blink.

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RE: Bulb

By murphyslabrat on 1/7/2008 4:56:03 PM , Rating: 2

Or, it could be intentional, for those dolts who enjoy siezure inducing, blinking lights.

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RE: Bulb

By MrTeal on 1/7/2008 6:20:11 PM , Rating: 2

That's strange, I always assumed that they would at least have a full wave rectifier, and that the flickering was due to the rectified waveform being unfiltered. Come to think of it though, I've used LEDs before with just a transformer and bridge rectifier, and never really noticed a flickering.

I assume that the strings of 35 lights are all connected in series. It should be a simple task to toss a few 4004's and a cap together in front of a string and pot it. Transformerless power supplies aren't as safe as those with transformers, but it wouldn't be any more dangerous that the live AC on the string anyway.

Thanks for the idea. :) I'll have to see if stores are still clearing out christmas lights.

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RE: Bulb

By Solandri on 1/7/2008 9:27:37 PM , Rating: 2

The lights on several newer car models flicker like this too. Very annoying when I'm driving. Lexus and most of the domestic brands. The electrical system on cars is DC, isn't it? I always assumed it was an energy saving "feature". Since LEDs can turn on/off almost instantly and the light doesn't have to be on 100% of the time to fool your eye into thinking it's on all the time, no sense wasting energy by having them lit all the time. Except certain people like me can see the flicker.

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RE: Bulb

By inperfectdarkness on 1/7/2008 1:03:44 PM , Rating: 2

to truly compare apples to apples, you'd need to post the temperature #'s, and the color accuracy of the lights you are using.

i've found that bulbs such as Phillips' "natural" are much preferred to standard incandescants. these are recognizable by the blueish tint on the outside. last year, i started using compact flourscents with the same "natural" light. i'm very satisfied.

that's not to say that LED's won't eventually replace everything. but to be fair, the old T-12 bulbs are still around, and will probably be until the 2nd coming of christ.

color accuracy is probalby most desirable to me. if the artist, graphic designer, etc all recommend light brand-x to me, then that's probably what i'd go with. i'd rather see true color than worry about feeling "sterile" or "warm" from the light.

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RE: Bulb

By inperfectdarkness on 1/7/2008 1:11:36 PM , Rating: 3

and before i forget...

led's are directional. great for spot lighting.

crappy for flood lights.

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RE: Bulb

By highlandsun on 1/7/2008 8:29:41 PM , Rating: 2

That's just a function of the built-in lens. Without the collimating lens, the LED output floods a complete hemisphere. You can get LEDs with different lens shapes...

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It will be nice..

By Clauzii on 1/7/2008 11:30:21 AM , Rating: 2

..when they are able to make the color more warm, like 'old' bulbs for normal home use.

RE: It will be nice..

By jbzx86 on 1/7/2008 11:47:23 AM , Rating: 3

I actually prefer the pure white light that LEDs can emit. I can't really stand the yellow glow from incandescents, as I find that it skews colors. Also, yellow is so damn drab. White is the way to go.

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RE: It will be nice..

By ChronoReverse on 1/7/2008 1:23:58 PM , Rating: 2

You know, I always hear about the "yellow" incandescent light bulb. Does everyone only ever use 40W bulbs or something?

I find the higher watt frost bulbs or even spots tend to give a pretty nice white light. That said, many of the bulbs that I use are the compact fluorescent bulbs since they use so much less power.

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RE: It will be nice..

By Ringold on 1/7/2008 1:39:36 PM , Rating: 2

Any woman that tries to do makeup based on what type of lighting she'll be in can tell you the difference. I personally can't stand compacts, and simply hope that LED's or something superior is available before we make like communists and make older lightbulbs illegal. If not, guess I'll just have to buy a half-decade supply... I wonder if the cops will monitor energy use and bust light bulb abusers like they do those growing pot? :P

I noticed on a Corvette, not the latest but the last one that still had the old-school headlights, the reading lights on the rear view mirror were LED and gave off a nice, 'natural' light by mixing various colors of LED's. I don't know if they still do that, but it was a nice effect.

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RE: It will be nice..

By Samus on 1/7/2008 1:41:43 PM , Rating: 2

The 'Daylight' CFL bulbs are usually rated somewhere in the 6000k spectrum. That's about the same as LED lighting. However, I agree with MK, that LED bulbs that I've seen don't flicker at all. They also don't have a warm-up time (CFL bulbs that are below room temperature tend to be dimmer and slowly approach the rated lumen output as temperature goes up)

But I'll add one last comment about exotic lighting. My personal office is lite with two 50-watt metal halide lamps powered by two 50-watt digital ballasts. It is by far the most superior lighting in existance: extremely efficient on energy per lumen, only beaten by LED lighting, but then again, LED lighting can't effectively output 5000 lumens using 50-watts without breaking the bank. 50-watt MH bulbs are $20 at Home Depot, Menards, etc, and last 2 years running 24/7. The best part is they don't burn out, they begin to dim. I've had a 150-watt MH light in my garage on an analog ballast (tends to flicker, like a street light, so not good for office) running non-stop for 5 years!

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RE: It will be nice..

By mindless1 on 1/21/2008 10:09:20 PM , Rating: 2

They're already able to make the color as warm as you could reasonably want it. There's a catch, in that typical white LEDs start out as blue light with a phoshorous coating that creates a yellow mix not 100% efficiently, so the further you drift away from blue the less efficient it is.

Since LEDs are (among other things) used in situations where efficiency is important, the bluer-white spectrum models tend to be more popular, until now where we're seeing more interest in use as ambient lighting for the masses.

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