Backing-out luminosity togo from lumens to radiant flux in W

[Andy Kellett]

Hi. Has anyone already done the work to back out the standard luminosity function so I can go from lumens at a particular wavelength to radiant flux in Watts? I have visible LED spec sheets with optical characteristics in lumens and I want to calculate the outputs in W. My NIR LED has specs in radiant flux in W because we can't see that. I want everything in W. I found the expression for the standard luminosity function here
https://en.wikipedia.org/wiki/Luminosity_function
but was hoping someone knew of a website or program that already does this.
Thanks!

 

[tech99]

Hi. Has anyone already done the work to back out the standard luminosity function so I can go from lumens at a particular wavelength to radiant flux in Watts? I have visible LED spec sheets with optical characteristics in lumens and I want to calculate the outputs in W. My NIR LED has specs in radiant flux in W because we can't see that. I want everything in W. I found the expression for the standard luminosity function here
https://en.wikipedia.org/wiki/Luminosity_function
but was hoping someone knew of a website or program that already does this.
Thanks!

Wikipedia says a Lumen is 1/683 Watt measured at 555 nm (green).
What pity illumination engineers do not simply use the same units as radio engineers - Transmitted Power and Isotropic Effective Radiated Power (EIRP) etc.

 

[Andy Kellett]

Wikipedia says a Lumen is 1/683 Watt measured at 555 nm (green).
What pity illumination engineers do not simply use the same units as radio engineers - Transmitted Power and Isotropic Effective Radiated Power (EIRP) etc.

Yes - I know why lighting engineers are concerned with the response of the human eye, but I'm exciting silicon! I will probably just back this out from blue to NIR and share with the group. Thanks for your response and help.