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Registered Member #2893
Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242
Both soda lime and brosillicate glass will transmit UVA just as well as they do visible light.
My concern is the polaroid sheet, RGB filter, indium-tin oxide, and liquid crystal solution. I don't think any of those will transmit UV very well, let alone all 4.
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062
hm... yes, i really need to try it with the frame.. interestingly i discovered a very useful trick where a lightscribe disk can be used as a template, so obviously enough UV makes it through for this to work.
EDIT:- it verks! 48V at 1mA and all diodes *seem* fine. confirmed stable uv emission using glow sheet. might need to add balancing resistors but i doubt it...
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
wow! great idea, and project. but i wonder how good your edge quality of traces will be when the resist is developed, then etched. i like photo etching, ive done it many times via OH transparency, i look forward to seeing your results.
Proud Mary wrote ...
It goes without saying that hexavalent chromium compounds are known carcinogens, so steady as she goes.
lol!
Proud Mary dont bum me out by reminding me of the consequences which concern radioactive and poisonous chemistry, they are so much fun to play with.
if you will all excuse me, I have some Nitrogen Triiodide calling out for me.
For new people: protect your eyes with this project, i.e. long distance to eyes, short time exposure to eyes, and dark eye glasses. (at least one of these, but preferably all three.)
Registered Member #27
Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058
It is important to remember that these LEDs are not really ultraviolet, they are violet or maybe ultra blue. The light passes through anything that we normally think of as transparent.
Instead of using SMD LEDs you can cut the top off a larger LED and get a perfectly even spread of light like this:
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
Bjørn wrote ...
It is important to remember that these LEDs are not really ultraviolet, they are violet or maybe ultra blue.
are they not emiiting at least 400 nm !? i realize these LEDs are not narrow spectrum like gas tubes, but they should be broadband centered on the emission spectra of UV at rated power.
Bjørn wrote ...
Instead of using SMD LEDs you can cut the top off a larger LED and get a perfectly even spread of light...
i was thinking the same thing but your post beat me too it. at least you wouldnt need 48V at low current.
you can also buy a device for photo cutting that is a flourescent scan lamp diffused plastic thingy. i cant remember what their called. but they give uniform visible light, maybe a mod coud be made.
Registered Member #2814
Joined: Wed Apr 21 2010, 12:28PM
Location: Scotland, UK
Posts: 24
HOW MUCH?!!11!
A bit pricey considering it's much the same as a white LED without the phosphor. I suppose it's the glass lens rather than a gel bead that adds to the cost. Which would need to be removed without damaging the LED.
I've bucketfuls of 2W white LEDs here, I wonder if there's any way to convert them back to UV....?
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Digital picture frame PCB etcher
48V at 1mA and all diodes *seem* fine.
