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Old 25th February 2005, 06:58 AM   (permalink)
Default Lumens & Lamina power LEDs

I have been playing with Lamina Ceramic's record-breaking BL-2000 emitters, in red and green. I have them hooked up to a heatsink and ran each at its rated currents. They are operating fine and not only warm to the touch.

The red is rated at 270 lumens and the green at 78 lumens. However, the green appears not only comparable, but slightly brighter than the red. Now the human eye does respond stronger to green photons than red, however, from what I understand about the "lumen" unit when applied to colored LED light sources the eye's response to that particular color is supposed to be factored into the unit. Or did I miss something?

I even called up Lamina and spoke to one of their app guys. He was a bit confused that the green was not a fraction of the red as well, although he did not seemed well prepared for this question.

It's not that I'm unhappy with the light output, but this question is nagging me. If anything, it could mean something is wrong with the red's output, but the individual emitters are all pretty even, the voltage drop is as expected, and its temp is fine (high operating temp makes the light output drop quite a bit).

Anybody really familiar with the lumen quantity? I've tried to look up a few pages and am still a bit unclear on how/if it's supposed to take into account eye response when the color varies.
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