Max Theoretical Lumen from 1 W?

katx · Aug 17, 2007

I am a scientist. Still I have had the hardest time in understanding or even getting info on Lumen.

I have found some stuff which has answered some of my questions but others remain.

Here is one question: what is the theoretical ceiling for the amount of lumen that 1 Watt of energy can produce?

Here is my answer: roughly 690.

Whatsayyouguys?

LukeA · Aug 17, 2007

241lm/W for white light, IIRC.

mdocod · Aug 17, 2007

I'm pretty sure it's a different answer for different wavelengths, as lumens are not a measure of light energy, but more takes into consideration how a human would interpret a particular wavelength.

I was under the impression that there is a peak around 530-570nm wavelength that we are more sensitive to, so theoretical lumens for 1 watt of energy is in the 400s in this green light.

katx · Aug 17, 2007

This is how I got my ~690 Lumens/W:

http://searchsmb.techtarget.com/sDefinition/0,,sid44_gci541730,00.html

Definition: "One lumen is the equivalent of 1.46 milliwatt of radiant electromagnetic (EM) power at a frequency of 540 terahertz."

"A frequency of 540 THz corresponds to a wavelength of about 556 nanometers (nm), which is in the middle of the visible-light spectrum."

Luminescent · Aug 17, 2007

katx said:
I am a scientist. Still I have had the hardest time in understanding or even getting info on Lumen.

Here is one question: what is the theoretical ceiling for the amount of lumen that 1 Watt of energy can produce?

Here is my answer: roughly 690.

Whatsayyouguys?

Pretty darn close. The figure most often quoted is 683 Lumens/Watt at 555nM (roughly the peak of human vision).

http://en.wikipedia.org/wiki/Lighting_efficiency

Max Theoretical Lumen from 1 W?

katx

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LukeA

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mdocod

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katx

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Luminescent

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