Has anyone been able to get a good idea of the cutoff wavelength of the retina screen after it is taken apart? Is it exactly 400nm, so that 405nm or 410nm wavelength LEDs would work well? I've seen how some of the absorption curves for the resin do cure up to 420-425nm, but seem to require much more energy (luminous flux?) to do so compared to the 405 or 410 range. But if the retina LCD panel blocks more of the 405nm than the 420nm part of the spectrum, this may be a wash.
I read a forum on aquarium builds where they were comparing the semiled 405nm to the ledgroupbuy 405nm (or 410nm). It seems getting a good quality, long lasting 405nm LED at a decent price is challenging. There seems to be a few stores that do reef/aquariums that have custom ordered large numbers, and sell individual ones. So what are people using for LEDs with success? It seems the ledgroupbuy 410nm LED can run with a 700ma constant current source.
I have read good things about the meanwell LDD-700H.
http://www.ledgroupbuy.com/meanwell-ldd ... ed-driver/. Hook that to a 48v 7.3a generic power supply, and use PWM via the arduino mega 2560 (w ramps 1.4). My electrical knowledge is rusting, but it is the case that a 48v power supply is more efficient than a 12v or 24v power supply. Are there other benefits besides being able to string more LEDs together in one series?
Or could one use something like this:
http://www.ledgroupbuy.com/inventronics ... r-700ma-1/ I'm not sure exactly how you would automate this to an arduino via PWM.
The large 20-100w panels would seem to be impossible to collimate the light, and would affect the resolution in the x/y. But by how much? Would it cause failed prints, or would the prints just turn out less sharp in the finer details? I know the ibox nano uses small 5mm leds with no lenses onto a monochrome screen, and some of those prints look rather good (compared to a filament reprap...).
Here were a few other ideas I had for a 400-420nm light source, so please comment why they wouldn't work:
1. actnic CFL 420nm bulbs/tubes - not sure how to compare the light output to 405nm LEDs and they would probably not last long with constant on/off cycles? (perhaps a shutter mechanism in the gap between light and lcd could alleviate this problem) These seem to be almost exclusively used for aquariums. There were some 9w ones made by coralife that use a g23 socket and are about $5-8 each and are about 7in long, but they also have 4ft long ones... There are $20 UV nail curing boxes that have four sockets which could be modified to line them up. This would at least be not too expensive, although even if it worked I'm not sure it would be cost effective compared to longer lasting LEDs. I just have no way of comparing the amount of light output at 400-420nm vs the LEDs, can't seem to find any of the technical info on them.
2. After seeing the 5mm leds of the ibox nano, I wondered if it would work to have smd5050 or smd5630 LEDs mounted to a circuit board spaced very closely together on a heatsink. They are cheap by the 100x and they are small enough to allow a more even light source. But again, being non-collimated would limit resolution and reduce actual amount of light going through the LCD because of scattering. I'm just not sure how much. 7020 LEDs are even more powerful, but it seems they don't come in the correct wavelength.
3. Finally, I wondered about this:
http://www.ebay.com/itm/30W-60W-High-Po ... 2ed3d15bd7 (all the links are purely for reference, not as an endorsement) Sorry to be so long winded, but some of these conversations are rather old.