raggie33
*the raggedier*
- Joined
- Aug 11, 2003
- Messages
- 13,540
say lumens per watt.but still have good color. im talking about white leds.will it be like cpus and get better faster and faster?>
in thery how bright can a led be?
- Thread starter raggie33
- Start date
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JonSidneyB
Flashlight Enthusiast
Some of the numbers I have seen are way up there. But not ready for flashlights I don't think.
jtr1962
Flashaholic
Theoretical efficiency depends upon the spectrum. Here are some maximum possible numbers:
200 lm/W (CRI 100)-continuous spectrum very close to sunlight
325 lm/W (CRI 98)-five color white LED source
345 lm/W (CRI 95)-four color white LED source
375 lm/W (CRI 80)-three color white LED source
430 lm/W (CRI 5)-two color white LED source
683 lm/W - 555 nm monochromatic green source
In summary, if you can emit light with 100% power conversion efficiency, you can get only 200 lm/W if you insist on emitting the entire spectrum but can do much better (325 lm/W) with only a slight decrease in color rendering. Dropping color rendering to around 90 will get you a further increase to roughly 350 lm/W. Outdoors where color rendering is a lesser concern you can do better than 400 lm/W. In practice I doubt LEDs will ever exceed 80% conversion efficiency so multiply all of these by 0.80. We'll probably reach 60% conversion efficiency within the next decade so this will mean white light with efficiencies of 120 to 250 lm/W, depending upon how full the spectrum needs to be.
I've heard that there are reasons why LEDs will never be 100% efficient although I don't know if these limits have to do with quantum physics or manufacturing defects which can be overcome.
200 lm/W (CRI 100)-continuous spectrum very close to sunlight
325 lm/W (CRI 98)-five color white LED source
345 lm/W (CRI 95)-four color white LED source
375 lm/W (CRI 80)-three color white LED source
430 lm/W (CRI 5)-two color white LED source
683 lm/W - 555 nm monochromatic green source
In summary, if you can emit light with 100% power conversion efficiency, you can get only 200 lm/W if you insist on emitting the entire spectrum but can do much better (325 lm/W) with only a slight decrease in color rendering. Dropping color rendering to around 90 will get you a further increase to roughly 350 lm/W. Outdoors where color rendering is a lesser concern you can do better than 400 lm/W. In practice I doubt LEDs will ever exceed 80% conversion efficiency so multiply all of these by 0.80. We'll probably reach 60% conversion efficiency within the next decade so this will mean white light with efficiencies of 120 to 250 lm/W, depending upon how full the spectrum needs to be.
I've heard that there are reasons why LEDs will never be 100% efficient although I don't know if these limits have to do with quantum physics or manufacturing defects which can be overcome.
