This is about direct color LEDs.
I've noticed that while LEDs whose output is specified in miliwatts have usually only a small differnce between the lowest and the highest bin (ie XT-E royal blue - lowest 500mw, highest 600mw), LEDs whose output is specified in lumens have this difference much higher (XP-E red ranging from 45.7 to 73.9). As all of you surely know, lumens are based on human's eye sensitivity. Because of that, a slight shift in wvl results in great difference in lumen output.
Now the theory (Cree red LEDs are what I'm interested in).
These LEDs have similar radiometric output (not so large differences) and the large differences between output bins is caused by wvl shifting up (off red-orange to deeper red). Can somebody confirm?
I can think of some reasons why is that difference so large, ie different technology (red x royal blue), keeping the best blue dies for white LEDs, or combination of both...however I find my theory quite possible.
In short, should I expect an XP-E red 73.9lm to have 1.6x (73.9/45.7) higher radiometric output than 45.7lm one?
I hope I put it understandable.
It's just a theory of mine and I could be completely wrong.
Looking forward to your responses!
a.
PS: Has anybody measured any red Cree LED with a radispectrometer? If so, PLEASE share the results.
I've noticed that while LEDs whose output is specified in miliwatts have usually only a small differnce between the lowest and the highest bin (ie XT-E royal blue - lowest 500mw, highest 600mw), LEDs whose output is specified in lumens have this difference much higher (XP-E red ranging from 45.7 to 73.9). As all of you surely know, lumens are based on human's eye sensitivity. Because of that, a slight shift in wvl results in great difference in lumen output.
Now the theory (Cree red LEDs are what I'm interested in).
These LEDs have similar radiometric output (not so large differences) and the large differences between output bins is caused by wvl shifting up (off red-orange to deeper red). Can somebody confirm?
I can think of some reasons why is that difference so large, ie different technology (red x royal blue), keeping the best blue dies for white LEDs, or combination of both...however I find my theory quite possible.
In short, should I expect an XP-E red 73.9lm to have 1.6x (73.9/45.7) higher radiometric output than 45.7lm one?
I hope I put it understandable.
It's just a theory of mine and I could be completely wrong.
Looking forward to your responses!
a.
PS: Has anybody measured any red Cree LED with a radispectrometer? If so, PLEASE share the results.
