Botboy3000 wrote:
Bad news. And this is really bad news. Our monitor screen is not UV transparent. All this time we assumed it was but we thought wrong. It's not SO bad though because there are monitors out there that have uv transparent glass and polarizers in them according to my research.
That is indeed an annoying setback, but at least your motor, controller, framework, and other components are still viable. Smile Have you investigated whether the LCD panel has some sort of coating that can be peeled off? I know that that is the case with some panels.
KermMartian wrote:
Have you investigated whether the LCD panel has some sort of coating that can be peeled off? I know that that is the case with some panels.

I have not. My prime suspect right now is the glass that is in between the polarizers but I will definately search online for information like that. Good thinking.

And yes, all our other pieces of the puzzle are still working. Very Happy
Ok. It's been a LONG time since this thread has been updated.

We have realized what the problem is with our monitor.
Get ready....

365 nanometers is just too high of energy. We have settled on the standard wavelength that most uv flashlights and things are in and that is lower energy 410 nm. This should work because after some more research we have found that most monitors only let frequencies lower than 400 (so radio waves to like, some of ultraviolet)

We'll get those ordered and see if we can get the stuff to cure!
Also, we are trying to think of a way to mount all the led's. Thoughts? We were thinking something like a lite-bright board but custom pcb's are expensive. I hop to get this project on its feet again. See you in the next update! Smile
Botboy3000 wrote:
365 nanometers is just too high of energy. We have settled on the standard wavelength that most uv flashlights and things are in and that is lower energy 410 nm. This should work because after some more research we have found that most monitors only let frequencies lower than 400 (so radio waves to like, some of ultraviolet)
Wat? The visible spectrum goes from like 400-780nm, and certainly monitors let their backlights through. Are you saying that they allow wavelengths below the visible spectrum through as well, or is there a finer point I'm missing?

Botboy3000 wrote:
Also, we are trying to think of a way to mount all the led's. Thoughts? We were thinking something like a lite-bright board but custom pcb's are expensive. I hop to get this project on its feet again.
Not as expensive as you might think, especially since you could get a small board holding 4x4 or 5x5 LEDs printed for ten for $14 shipped from somewhere like DirtyPCBs, then just tile them over the area you want to cover. However, another option would be cheap perfboard.
You could alternatively make a PCB, Ben Heck has a pretty good tutorial on it https://youtu.be/N3DGbwVXyN8
The led's we found are like $0.02 each so We'll get like 1000 of them. and if we wanted a pcb it would have to be like the size of a sheet of paper. and THOSE are expensive.

Yeah, Kerm you're right. I got the thing backwards. The filter lets light from longest wavelengths to wavelengths at the beginning of the UV spectrum. and the end of where that works is 400 nm so 410 nm should go through the filter. Sorry for any confusion.
Since a sheet of A4 paper is ~20cm x 30cm, and DirtyPCB will give you roughly 10x 2"x2" (5cm x 5cm) PCBs for $14 shipped, you could cover your A4-sized area with 30 PCBs, for a cost between $42 and $56. Each board would have power connectors on at least two edges and space for a lot of parallel LEDs with current-limiting resistors covering most of the area. You can also get an A4-sized area of perfboard for less than $20, which might be a more economical choice, if a little less professional looking.
Yep! I found a piece of perfboard about a half the size of a A4 sheet of paper and buying two of them would cost just under $7. All the led's are going to be about $20 so for under $30 we could have the lighting system! Very Happy And the perfboard I found even has traces going up the length so all we'd have to do is solder the components in and we wouldn't have to make our own traces. I cant wait till next weekend (or the one after that possibly) to get this started Smile
Great find; I'm glad there was some perfboard that fit your needs! At what store did you find the perfboard, and which one is it? Do you have a link? Good luck with all that soldering. By the way, I strongly, strongly recommend testing how much the material cures with a white and a black LCD with these LEDs, because there's probably a slope rather than a hard edge to how much it blocks different wavelengths of light. Therefore, it might block 10% of 600nm, 95% of 410nm, and 100% of 400nm, which would be problematic for you. I doubt it blocks 10% of 410nm and 100% of 400nm.
KermMartian wrote:
It might block 10% of 600nm, 95% of 410nm, and 100% of 400nm, which would be problematic for you. I doubt it blocks 10% of 410nm and 100% of 400nm.


Hmm... That's a good point. I guess I can try to research that but with the huge variety of monitor types it could be tricky.

I lied on the price. It will be just under $10 for the perfboard. Here's what I found on ebay.

I knew that radioshack had perfboard but what I've found in recent years is that ordering online is so much cheaper. Yeah, soldering all those hundreds of leds is gonna be a huge task. Not impossible though. just time consuming
Wow, and you even found a place with a US shipping address, so you won't have to wait a month for it to come from China. Very nice. Good luck researching the monitors as well; I wouldn't know where to start with that.
Thanks. I'll probably try to search the brand of monitor I have and go from there. There can't be too much variety in the lcd screen part I don't think. We'll see. I'll try to order the materials tonight and maybe solder throughout this week and next week. This should be interesting how it turns out!
*bumpity bump* What's been happening with this project in the past month? Were you able to set up the grid of LEDs and test them with the monitor that you have? What did you discover?
So, The monitor we have is not letting any sort of UV light through. I have gotten the idea though that a monochrome screen will give us better results. I did make a small UV LED array ~300 of them but then I realized they sent us the wrong wavelength Razz So we tested cure time without the screen and it was under 2 seconds! And we got it about 5 mils thick is what my dad said. I also got a little screen going with my arduino that shows print stats on it which is cool I guess. and now everything except the monitor is being powered by one computer power supply that I found. That's all so far. I hope this project will move forward with the testing of a monochrome screen. Smile
Have you explored trying to scrape or dissolve the polarizing filter off your monitor, in case that's blocking UV? Unfortunately, I don't know if that would also prevent it from blocking any UV light at all at "dark" pixels. I'm glad that the wrong-wavelength LEDs didn't prevent you from carrying out a successful test, a a 5-mil layer cured in 2 seconds sounds like an excellent balance of speed and detail to me. I look forward to hearing where your experiments go next.
Haha! I actually have a monitor that I did that to so that you can only see the screen using some modified 3D glasses. But I do think that peeling off the top most polarizing filter would indeed make nothing be able to be black because when you're not wearing the glasses to see this other monitor it is compeltely white. In order to get the black pixels back you'd need to add another polarizing filter which is the glasses.

UV light can be polarized (or not), just the same as anything else. If the monitor generates UV, I would guess there's a separate filter for blocking it.
I know that UV can be polarized, we have gotten the concept of shining UV light underneath the monitor and showing a pattern on the screen and the makerjuice did cure in that pattern, just took over two minutes as opposed to two seconds without the screen. My hope is that because monochrome screens work differently we'll get different results.
Botboy3000 wrote:
I know that UV can be polarized, we have gotten the concept of shining UV light underneath the monitor and showing a pattern on the screen and the makerjuice did cure in that pattern, just took over two minutes as opposed to two seconds without the screen. My hope is that because monochrome screens work differently we'll get different results.
Ah, that's good to hear that the pattern worked, albeit slowly. As elfprince13 was implying, I bet there's a separate UV filter on one side of the monitor; it seems unlikely (but possible) to me that the LCD glass itself is blocking UV.
"bump" So, how's it going, Botboy? I hope that progress is being made?
  
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