UV LED help please.

Flashlight Modding and DIY Parts
1

Hi all,

This is a project I am working on for someone. They would like to cure this UV paint with a flashlight.

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The emitters we will be using are 365mn, 395nm and eventually a 400nm.
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I have some basic questions about working with these LEDs.
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Safety

  1. Exactly what eye protection do I need to be using?
  2. What other safety concerns are there with this type of led?
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    Construction
  3. Can I use traditional plastic optics like the 3x and 4x we use with common LEDs? I put a UV dropin of some kind in my old surefire 6p and it melted the acrylic lens.
  4. Based on the above data sheet is it at all reasonable to think I can make a UV light strong enough to cure that paint using a battery pack of 3x 18650s? I don’t know how efficient regular UV bulbs are vs LED so what would be a 400 watt equivalent?
  5. Do I need to spend hundreds of dollars getting a nichia or some expensive UV LED or are the budget ones from mouser and digikey just as good?

Thank you all in advance!

2

A 400W equivalent? :open_mouth:
I don’t know about that. Current single die uv leds are 0.5 to 1W output power typically. But there are sime high output uv-COB leds out there with much more output. I do not know much about them and thus can not recommend one.

To answer some of the other questions:

-You do not need Nichia leds for maximum output, some cheaper leds have just as good output, but do not have such a clean spectrum, but that is irrelevant for use as a curing light. Search Digikey for LiteOn leds, they fit a standard XP-G pad.

-For 365nm, standard safety goggles made of polycarbonate block it almost completely. For 400nm leds you need the yellow glasses. You can always check glasses by shining the uv-light through the glasses onto a piece of copier paper, if it does not give the blue fluorescence, the glasses are ok.

-The efficiency of 365nm-400nm uv leds have improved drastically in recent years, in output power it is not far under the blue leds used in white leds.

-Carclo optics work well for 400nm, but block 365nm almost completely. Again check with the copier paper test.

3

I purchased ” these”:https://www.amazon.com/gp/aw/d/B000USRG90/ref=mp_s_a_1_5?ie=UTF8&qid=1495225319&sr=8-5&pi=AC_SX236_SY340_FMwebp_QL65&keywords=uvex+safety+glasses&dpPl=1&dpID=41xZuWrtIsL&ref=plSrch#productDescription_secondary_view_div_1495225368890 for curing NOA61 using 365nm uv.

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Very helpful. Especially the bit about the LEDs that have an XPG foot print.

Thank you.

5

would tanning goggles work?

6

djozz

I found the Lite-On emitter in the 365nm but digikey doesn’t stock the 395nm. Are there any others your aware of that have a cree foot print?

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look for 3535 leds. many on ebay, xp footprint, thou they are hit and miss quality wise. i have few 395, as well as 400-405 iirc, i can send you 1 of each for testing, they worked fine for my purposes, they are on stars, but i unsolder them and use with triples. pm me if interested,