Hi,
Someone electro, and Tarsil, good to see you guys discussing this..'power' is really out of my field, I'm more of a 'control freak'
I guess its a careful balance of efficiency, reliability, cost, and size (who wants to use 700 5mm led's?).
As for 'viewing angle', I wouldn't worry, I doubt very much that any 'commercial' devices would use the LED's 'as is', they would probably put them in a diffuse enclosure, or at least behind some frosted acrylic to mix the colours better and scatter light. The luxeons seem like a good idea, although, as tarsil pointed out...they do disipate a lot of power as heat. Maybe I'm missing the point here, but I always though that the reason some LED's can take more current (and therefore, be 'brighter') than others was purely down to how much current they could take and for how long....and this would be down to heatsinking. The luxeons are designed specifically to disipate heat in a certain way, and from the app notes i've read, careful PCB design should be used for non-heatsinked ones. And they often quote 'peak power', not continuous. I mean, if you pulse a standard 5mm LED with a massive amount of current (within its limits), and give it time to cool..it can be used as a flash for a camera, now THATS bright.
I ismply don't have the money right now to buy up some 'super LED's' and test em. I do'nt know if anyone has seen these 'strips' of LED's, enclosed in a translucent tube, they seem to do the job quite nicely:
**broken link removed**
Of course, you could design your own control circuitry/power driver, And I'm not sure if they are what you are after, but I've got a few of the LED's used there and they are BRIGHT. Not luxeons, but for size, they do the job nicely.
Anyway, as I said, I'm a bit out of my depth when it comes to working out the right 'lumens' needed, because you can't really compare LED's to incadesant lighting, with light scattering, efficiency, plus the fact that our eyes have different sensitivity to different wavelengths, so blue and red won't appear as bright as yellow/green.
Keep it up!
Blueteeth.