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Print 71 comment(s) - last by mindless1.. on Dec 23 at 10:54 PM

Scientist hope to put LEDs to work in brilliant new ways

LEDs, light emitting diodes, are a very old invention, with the first visible-light diode being invented in 1962.  They consist of a junction of semiconducting material, such as a silicon or gallium compound.  However, scientists today are looking to teach this old dog some new tricks, and putting LEDs to work in a plethora of creative uses.

The magic is in the material.  While LEDs have been around for a long time, new and exotic materials are being used and older materials are being tweaked and reformulated to provide, a wider range of colors, brighter light, and higher efficiency.

The result is that LEDs may soon be permeating our lives in new ways.  LEDs are already invading the automobile headlight industry and are in high demand due to their superior life and brightness. 

Now one place scientists are looking to plant the LED is in the home.  Tungsten lightbulbs have a very low 5% efficiency, compared to modern LEDs, which have around a healthy 40% efficiency.  The result is power savings, increased brightness, and superior life.  Obstacles standing in the way of this development are the still higher cost of LEDs and the fact that LEDs' white light has much more blue than sunlight or natural bulbs.  However, these obstacles are fading as costs slowly drop and scientists develop better material blends to provide more yellow to the LED's emissions, making for a warm light that would be welcome in many a household.

Scientists are also looking to put tiny LEDs to a new use in the lab and eventually in commercial internet connections -- quantum cryptography.  Tiny streams of photons in the system would pass from the LED to the a detector.  Any interception of the beam (ie. snooping) would result in the signal being altered, as per the observer effect.  Such a system, when properly implemented would be in theory immune to any sort of malicious interception between the sender and the receiver.

Yet another use for the little lights has been proposed by scientists -- this one with promise of bringing new high-tech hope to impoverished regions.  One of the world's largest problems is the lack of clean drinking water in third-world nations.  Chemicals can be used to treat drinking water, but they are often expensive, toxic, and require a large amount of infrastructure.  A frequently used alternative is high-energy UV light known as "deep UV", emitted from special UV bulbs.  Passing a beam of this light through water kills most bacteria and destroys most viruses cleanly and simply.  The issue with this system is bulbs constantly need to be replaced and are two bulky for small scale use.

Scientists feel the answer is deep UV LEDs.  While they are still working on perfecting the materials, researchers,  such as Dr Rachel Oliver, an LED researcher from the University of Cambridge, think it is just a matter of time before the optimal combination of materials is found. 

"Deep-UV can't be made from the combination of materials we're used to, although I certainly think it's possible," Dr. Oliver stated.

Dr. Oliver is among many researchers striving to put LEDs to use in new and creative ways.  She sees LEDs being commercially implemented in the aforementioned uses within 10 to 20 years.

For now these prospects still remaining cost prohibitive and are dependent on material breakthroughs, but the future sure looks bright for these little devices.  And companies are looking to put LEDs today to a different and even more outlandish use -- clothing -- every airport security officer's worst nightmare

Whatever their form, LEDs are transforming the way we light and see our world.


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RE: Consumer Replacements Available Now
By melgross on 12/16/2007 4:29:34 PM , Rating: 2
I bought two of these to experiment with. They cost $70 apiece. Pretty expensive for 380 lumens. They have more powerful models, but they cost more per lumen.

http://earthled.com/vr7.html


RE: Consumer Replacements Available Now
By GeorgeOrwell on 12/17/2007 2:30:59 AM , Rating: 1
How does the quality of the EarthLed LED light compare to ordinary tungsten incandescent lights (soft white and clear bulb) and to halogen lights?

I presume the light quality of the "EarthLed" light bulb is far better than the white LED bulbs that are found in flashlights?!?


RE: Consumer Replacements Available Now
By 91TTZ on 12/17/2007 7:14:55 AM , Rating: 2
quote:
I presume the light quality of the "EarthLed" light bulb is far better than the white LED bulbs that are found in flashlights?!?


That's doubtful, since they use the same 1 watt LEDs that many flashlights use.


RE: Consumer Replacements Available Now
By GeorgeOrwell on 12/17/07, Rating: 0
RE: Consumer Replacements Available Now
By mindless1 on 12/23/2007 10:46:26 PM , Rating: 2
I wouldn't say "scam", because buying 7 x 1W LED flashlights isn't going to be much if any cheaper than that bulb is.

It is a niche product, naturally it will cost more. However, it will be brighter than many LED flashlights for two reasons:

1) LED flashlight uses a battery which exhibits voltage drop running high current LEDs, while the supply for this wouldn't necessarily have to.

2) LED that run cooler put out more light and last longer. A flashlight is a difficult environment for an LED if meant to (designed well to) run for more than a few minutes at a time as there is limited heatsinking space available and even if it were well sunk to the exterior of a metal bodied light, it would get uncomfortably warm to hold in your hand after running for about a dozen minutes or more.

To put pricing in perspective, that bulb uses Cree 1W LED. Now 3W Cree LED that are more efficient are under $5 each in volume. Add maybe $5 for a driver circuit and $5 for a custom enclosure (bulb, heatsink, etc all integrated) so in theory today you could have a light that produces 3X that much light at a total cost of

7 x 5 + 5 + 5 = $45, BUT we have not yet built any other company overhead or profit into it yet, and it wasn't long ago the 1W LEDs cost as much as 3W cost now.

In other words, for the same money you can do better today but the price is not exceptionally high for what it is.

If this tech interests you I suggest checking out the offerings at http://www.dealextreme.com as they have the 3W Cree LEDs as well as many especially cheap driver boards, although most are set up for flashlight use but given the cost savings, some inventiveness would allow their use. For power you might pick up a small switching supply from one of the electronics surplus 'sites on the web, possibly even completely forgoing the driver boards if you have the right supply. For example a tweaked 12V switcher can be made to put out 14.8V which might do nicely to power 4 LED in series at a 3.7 forward voltage, and there are many tiny little wallwart sized 12V 1A switchers powering everything from routers to modems to scanners, etc, etc. so they're readily available.


By mindless1 on 12/23/2007 10:54:13 PM , Rating: 2
Correction - a better flashlight won't suffer so much voltage drop as it will have a better regulator design, but the heat factor is still present.

I don't agree that white LED is worse that CCFL for reading or detail work, I feel you just didn't have an LED based product that put out nearly as much light as a CCFL bulb you'd compared it to, and most flashlights try to focus for high intensity not broad beams which is harder on the eyes producing both glare and dark surrounding areas. Except casing light a long distance outside, many LED products do seem to try to focus the beam too much IMO.


"Nowadays, security guys break the Mac every single day. Every single day, they come out with a total exploit, your machine can be taken over totally. I dare anybody to do that once a month on the Windows machine." -- Bill Gates














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