Retina iPad Display

[AndersonTa]

Thanks, dudes!

Yeah, now to figure out how to make the entire assembly for the LCD/LED array. Having the vat have to be so close to the LCD surface is a real design constraint.

Phife: Are you building a frame around the LCD to hold it in place and sacrificing some print area (kind of like creating a bezel)? Or what are your thoughts on a fixture for the LCD? Seems like without sacrificing some print area (or at the least the black tape area on the front side), you will have to have some sort raised border.

[Phife]

My current idea is just to have the LCD laying on some clear acrylic or polycarbonate. Maybe 1/8"-1/4" thick to support the LCD from behind, then another layer on top of the LCD with a recess for the LCD's thickness and a cutout in the top layer that exposes just the active area of the LCD.

Kinda sandwich it between a clear sheet and another sheet (top sheet doesnt have to be clear).

Or, perhaps the LCD optically bonded to some clear acrylic on both sides, no cutout and the LCD gets glued to each side using some LOCA glue.

Some basic experiments show that a protective clear sheet can be placed on top of the LCD and optically bonded to it. This does not affect the clarity of the image, you are basically extending the clear image out to the surface of the protective clear sheet.

Ive been super busy with work lately so I havent had much time to work on it. Hopefully soon.

[AndersonTa]

A lot more testing...overall the LED array I got from Phife is doing its thing, resin is curing. Not the most ideal setup on many aspects, but nice from proof of concept.

I plan on doing a more detailed write up once I get to a stable point, for now you just get bread crumbs .

Overall setup: https://www.dropbox.com/s/zys8f7z1wyv37 ... 4.mov?dl=0

Resin curing: https://www.dropbox.com/s/7xpwa6e87ezkt ... 2.mov?dl=0

So I'm sure most will gripe about the cure times, yeah it took a while...but keep in mind a couple of things:

1) I'm at only 2A for current, I can increase it and should reduce the time (PSU I'm using is up to 9A, though I think the LED driver I'm using might not be rated to go that high)
2) I'm using uncolored resin, having pigments/dyes will likely help in reducing cure times from more absorption.
3) The array is def not placed in its best position, def hot spots the way I had it.
4) I'm not DIRECTLY on the surface, def a few mm's above.

[AndersonTa]

Figured we could use this info, specs for the iPad screen. Would be useful for CAD.

http://www.adafruit.com/datasheets/LP097QX1-SPC1.pdf

[AndersonTa]

Did some more testing having the LCD raised up about 1.5" from the top of the LED array. At 36V and 5A I'm getting cure times with MadeSolid Black resin at about 8 secs per layer (~<50 microns). Not bad! Again it was just to see curing speeds, no real structures/patterns to test for accuracy)

I'd like to figure out how to get the working distance a bit closer. That means cooling becomes much more critical having the LCD closer, but you then get the benefit of a more compact build (which is kinda one of the big benefits in going LCD.

[PomeroyB]

Your resin curing video has 404'd.

I've been looking into water cooling hot ends for FDM printers... It's way more efficient than air cooling. If you mount your LED pcb to an aluminum heatblock and set up a small radiator, I bet you could easily keep it cool.

What kind of wattage are you expecting to reach?

[AndersonTa]

[PomeroyB]

Just keep the printer submersed in water while it's printing! Easy solution!

[cncbasher]

AndersonTa

if it's just radiant heat use some small fans to pull the air out the area , but also place a fan low down and push air in , this will cause the air to evacuate the area quicker ,
Radiant heat is always a problem, also take a look at how much power your using , it may well be a simple matter of less power is better ..
Watercooling is fine if the Diodes creating the heat , and is far more effective than air , but in this case it wont help .

[AndersonTa]