Converting Lumens to Photons and Energy at Varying Wavelengths

  • Thread starter emcyroyale
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In summary, the conversation discusses ways to convert lumens to photons or energy at different wavelengths, specifically for LED lights. The speaker is seeking help in determining the theoretical energy emitted at different wavelengths, including those outside of the visible spectrum. They also mention the importance of understanding units in order to make progress in their calculations."
  • #1
emcyroyale
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Hello everyone,

My issue is regard a conversion from lumens to ~photons or energy at varying wavelengths. I am trying to find a way to determine the amount of energy an led can emit at different wavelengths. I figured because E = (h*c)/λ all I would need is to determine an photon emission. Most of the data sheets give Lm/W and the viewing angle. I know that Cd = Lm /(2π(1-cos(θ/2)), but that's as far as I got. I need a definite way to calculate the theoretical energy being emitted at different wavelengths. If anyone can help me finish what I started or help me discern a better way of find this it would be much appreciated. Also what would I do for wavelength out of the visible spectrum? For most UV or IR leds I have mW/sr @ mA, viewing angle and the basic electrical properties.
 
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  • #3
UltrafastPED said:
You will go farther and faster if you understand the units:
http://en.wikipedia.org/wiki/Lumen_(unit)

would you like to fix your link so it gets to the correct page please
as I have done in the quote of yours :smile:

Dave
 

What is the conversion factor for converting lumens to photons?

The conversion factor for converting lumens to photons is approximately 1 lumen = 4.6 x 10^18 photons. This factor may vary slightly depending on the specific wavelength of light being measured.

How do you convert lumens to energy at a specific wavelength?

To convert lumens to energy at a specific wavelength, you will need to know the spectral power distribution (SPD) of the light source. The formula for this conversion is: Energy (J) = Lumens x SPD x 1.46 x 10^-19. The SPD can be found through a spectral analysis of the light source.

What is the relationship between lumens and energy at varying wavelengths?

The relationship between lumens and energy at varying wavelengths is not linear. This means that the amount of energy associated with a certain number of lumens will differ depending on the wavelength of light. For example, 1 lumen of blue light will have a different energy value than 1 lumen of red light.

Can lumens be converted to photons and energy for non-visible wavelengths?

Yes, lumens can be converted to photons and energy for non-visible wavelengths. The conversion factor and formula will remain the same, but the SPD used in the calculation will be specific to the wavelength being measured.

Why is it important to convert lumens to photons and energy at varying wavelengths?

Converting lumens to photons and energy at varying wavelengths is important for accurately measuring and understanding the amount of light energy being emitted from a source. This information is crucial in many fields, such as optics, astronomy, and photobiology, where the effects of light at different wavelengths can have significant impacts.

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