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k_general
Joined: 01 Nov 2008
Posts: 9
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 22 Dec 2008 17:42 white led wikipedia |
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Hi
in the optical communiction course i need to know information about white led in the following
1-advantage
2-applications
3-structure
4-material
5-state of art
6-efficiency
and and more information
so please can any one give me link to any site include this information
or any reference could help me to do my research
please i need it fast
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Google
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22 Dec 2008 17:42 Ads |
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Audioguru
Joined: 19 Jan 2008
Posts: 1148
Helped: 95
Location: Toronto area of Canada
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22 Dec 2008 21:30 information about white led |
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A white LED is used as a light, not for communications.
An IR LED is used for communications.
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k_general
Joined: 01 Nov 2008
Posts: 9
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23 Dec 2008 6:25 report of white led |
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| the teacher of the course want us to make a report about white led about what i written below !!
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k_general
Joined: 01 Nov 2008
Posts: 9
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23 Dec 2008 19:18 white led summary |
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| So any one can help me ??
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Audioguru
Joined: 19 Jan 2008
Posts: 1148
Helped: 95
Location: Toronto area of Canada
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23 Dec 2008 19:32 nanocrystal-coated led |
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| Ask your teacher to help you.
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k_general
Joined: 01 Nov 2008
Posts: 9
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25 Dec 2008 17:04 more white led is important |
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| she told me to search over the internet for that !!
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FvM
Joined: 22 Jan 2008
Posts: 5161
Helped: 767
Location: Bochum, Germany
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mister_rf
Joined: 27 Feb 2008
Posts: 243
Helped: 59
Location: Romania
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25 Dec 2008 17:52 white led structure |
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Also some details here:
http://www.ledsmagazine.com/
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k_general
Joined: 01 Nov 2008
Posts: 9
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26 Dec 2008 12:50 possible questions on white led |
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thank you for help
now i will try to get the information i need
Added after 1 hours 2 minutes:
I still have trouble on searching over the internet so i think if any one can give me link to any reference in this field i think i can have the information i want quickly
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Sherifftech
Joined: 05 Jan 2009
Posts: 2
Location: U.S., Pennsylvania
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05 Jan 2009 17:27 information of white led |
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I think you need to start by realizing (you may already know this) that white LEDs are actually blue LEDs with a specialized phosphorous coating. (The coating is actually yellow in color.) There has been some recent breakthroughs in technology heading towards nanocrystaline coatings during the die fabrication stage to produce a white LED that is immensly more efficient. Here's an article about this.. with comparisons to other lighting technologies. http://news.softpedia.com/news/Nanocrystal-Coated-LEDs-Emit-True-White-Light-77798.shtml
Another good source is from one of the leading white LED manufacturers... http://www.philipslumileds.com/technology/whitelighting.cfm
The costs of replacing incandescant and CFL lighting with LEDs is extremely expensive right now as the efficiencies are relatively low (watts per lumen), and the design and packaging is rather expensive. Thermal management is extremely important as the light intensity demands increase. I've had the privilege to work on a few very high end LED lighting projects, one of them being the worlds brightest white LED light engine at 28,000 lumens @ 1400 Watts, which was a water cooled 5 inch square light source that contained over 1200 LEDs. (http://led.linear1.org/brightest-led-array-record/) This technology is not very cost effective when compared to what's currently available, but it is possible.
One other option for white LEDs is to build RGB light sources (red-green-blue) and individually controlling each LED to dial in the desired color temperature. Color temperature is another factor that is important in white LED lighting, if the light is too bright or too cool it can be distracting or even damaging. The standard for room lighting hovers around 5500 degrees Kelvin. http://en.wikipedia.org/wiki/Color_temperature This color temperature requirement also comes in to play when selecting phosphorous coatings paired with appropriate wavelenght blue LEDs.
Here are a few more leading manufacturer links that shoud help...
http://www.luxeonstar.com/
http://www.ledsmagazine.com/news/4/4/15
http://www.laminaceramics.com/
I hope some of this helps you out...
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