Build Your Own SLA/SLS

I've been doing some research on the LED source for creating a LCD based 3d printer. The following are some potential sources:

LED:

3W 410nm LED
$2.60 https://www.dx.com/p/jr-3w-410nm-3w-410 ... ite-173533

1W 410nm LED
$3.14 http://www.dx.com/p/high-powered-1w-uv-led-emitter-4334

Lenses:

20 Degree Lens
$1.61 http://www.dx.com/p/20-degree-angle-led ... FG7mvTF_dE

120 Degree Lens
$2.28 http://www.dx.com/p/120-degree-angle-le ... FG7pvTF_dE

8 Degree Lens
$1.61 http://www.dx.com/p/8-degree-angle-led- ... FG7rfTF_dE

45 Degree Lens
$1.87 http://www.dx.com/p/45-degree-angle-led ... FG7svTF_dE

30 Degree Lens
$2.19 http://www.dx.com/p/22mm-30-degree-cond ... FG7tvTF_dE

Anyone familiar with optics want to help identify which would be best suited for taking the output of the LEDS shown at the top and creating a uniformal projection, jump in. These are great and cheap leds. I have also bought from DX and their stuff is pretty good for the price.

I would imagine the specs of your LEDs, especially the angles, would be dependent on your PCB lay out. You want very even lighting, any overlap and you get hotspots.

So you might have to pick one and design the pcb accordingly or vice versa.

CidVilas, I've been thinking about the engineering behind doing something like this for the last night or two. Essentially the answer to your question about which lens to use is 'it depends'. without any other knowledge of the optical layout of the projector it would be difficult to say which lens to buy. If I had to guess, they would homogenize the light at some point in the system by diffusing it with a micro lens array. You'd want to illuminate the backside of this array with roughly collimated light (i.e. the lens creates a parallel beam coming out, like a laser pointer) You'll need to take a look at the size of the micro lens array and see how large of a collimated beam you'll need, and the divergence angle of the LED you chose, then select the appropriate lens from there.

I'm tempted to get a cheapo DMD style LED projector just to rip it apart and see if a mod like this could be made.

Here is an article that explains how an LED projector is illuminated. it should get you started on how to replace the LED if you're creative .

@CidVilas

See this thread for other options. You don't need a UV LED with a LCD:
viewtopic.php?f=12&t=84&start=210#p9616