chrisewolf

Hey guys, I am (again) a bit confused about a topic in photometry and I hope someone can help me out! I am taking measurements under certain angles to the surface normal of an LED and measure the Luminance L(cd/m^2)=(lm/m^2/sr). To obtain the illuminance I have to integrate over the solid angle. I know from the detector that the measurement angle is 0.2 degrees. The luminance does not change over azimuth so I integrated that out right away and I centered the azimuth at x. lets say I took a measurement under an angle to the surface normal of 50 degrees and I measured L=150 cd/m^2 can someone check the attached calculation and comment if that is right? Thank you very much in advance Cheers, Chris

Thank you very much for your explanation! Radio/Photometry is one of most confusing topics I have ever worked on, especially when authors are mixing up the quantities, symbols and units!

Thank you for your swift reply! I wonder if you could tell me in short how the method of measurements differ? Both are (presumably) measured using a photodetector (Si-diode etc), right? Thank you in advance!

Hello everyone! I am having a bit of a problem understanding a paper. Usually the authors use the electroluminescent spectrum to describe an emitter, but in this paper the radiant power is constantly cited. What is the relation of these two? Usually the EL spectrum is a.u. vs wavelength and radiant power is (in this paper!) W/(sr m^2) (usually called radiance). Can these two quantities be converted (as the time information is not known)? best regards, Chris