Looking for recommendations for UV LED flashlight near 365nm

[Antares]

I'm looking for recommendations for a UV LED flashlight. I know this has been asked a million times and I've looked at a lot of the threads, but I've also found a lot of models for sale and wondering if anyone has experience with them to help narrow it down.

These are my preferences:

* The lower the wavelength the better, approaching 365nm.

* The higher the UV intensity / the less visible light the better.

* Runs on common batteries, like alkaline AA's or AAA's. Ability to use NiMH or lithium a bonus.

* Compact, perhaps 3-AA size or smaller.

* Ideal would be something good for close up use but also effective at longer range like 10-20 feet.

* Under $50, but I'd consider more if there's a good reason for it.


Here are some of the lights I've seen, roughly in ascending order of advertised wavelength and price. Does anyone have any experience, recommendations, or opinions regarding these models, or others? I've purposely left out the Photon Micro -- I don't want that size / type of switch. I've also excluded lights with wavelength longer than 385nm.

The 5 x Nichia 365nm light for $55 seems like a pretty good deal? Or would I be better off with an Arc? Or for half the price, perhaps the Streamlight Stylus UV (at 365nm or 375nm -- can't tell for sure) or the 9 x 375nm from ledwholesalers.com would be a good deal? At the low end there's a 1 x 375nm light and a couple of 380-385nm lights for less than $10. (These prices don't take shipping into account.)


www.ledwholesalers.com
5 x Nichia 365nm ; 3-AAA ; $55


www.tek-tite.com
2 x 365nm or 2 x 375nm ; 3-AA ; $40


www.tek-tite.com
4 x 365nm or 4 x 375nm ; 3-AA ; $50


www.xenopuselectronix.com
8 x Nichia 365nm ; 2-AA (alkaline, lithium, NiMH) ; $112


store.advancedmart.com
1 x 370nm ; 1-AAA ; $18


store.advancedmart.com
12 x 370nm ; 2-AA ; $20


store.advancedmart.com
28 X 370nm ; 3-AAA ; $30


www.ledwholesalers.com
1 x 375nm ; 1-AAA ; $6


streamlight.com
1 x 375nm ; 3-AAAA ; $20ish
(Streamlight provides inconsistent information about the wavelengths of their devices in different documents. The web page and PDF fact sheet say 365nm, the PDF info sheet says 375nm.)


www.ledwholesalers.com
9 x 375nm ; 3-AAA ; $25


streamlight.com (Twin-Task 51010)
3 x 375nm & 3 x 390nm ; 3-C ; $40ish
(Again with the inconsistent information. The web page says 365nm, the PDF info sheet says 375nm.)


www.arcflashlight.com
1 x Nichia 375nm ; 1-AAA ; $40


www.maxmax.com (16LED375)
16 x 375nm ; 1-CR123A Lithium ; $78


The following 9-LED models appear to me to possibly be the same model, or at least using the same body, perhaps stemming from this article?
www.instructables.com

9 x 380-385nm ; 3-AAA ; $7-40

www.blacklightshop.com
www.ledwholesalers.com
www.blacklightworld.com
www.teachersource.com
www.batteryjunction.com


www.lighthound.com
12 x 380-385nm ; 3-AAA ; $10


www.ledwholesalers.com
7 x 380-385nm ; 3-AAA ; $15


www.ledwholesalers.com
32 x 380-385nm ; 3-AAA ; $25


www.ledwholesalers.com
51 x 380-385nm ; 3-AA ; $27


store.advancedmart.com
12 x 385nm ; 3-AAA ; $14


www.batteryjunction.com
14 x 385nm ; 3-AAA ; $15


www.ledwholesalers.com
21 x 385nm ; 3-AAA ; $18


www.delasco.com
9 x 385nm ; 3-AAA ; $44


www.jackstoolshed.zoovy.com
4 x ?nm ; 3-AAA ; $13


www.spectrum-scientifics.com
8 x ?nm ; 3-AAA ; $20


www.professionalequipment.com
4 x ?nm ; 3-AA ; $50


Several flashlights with unspecified wavelength
store.advancedmart.com
www.riskreactor.com

 

[niner]

The 5 x Nichia 365nm light for $55 seems like a pretty good deal?

www.ledwholesalers.com
5 x Nichia 365nm ; 3-AAA ; $55

It kind of depends on your applications. I just got the above light. It is direct-drive w/ a single resistor, all five emmiters are parallel, total at 100ma. I use it to cure small area of adhesive. It works okay, takes longer than I would like, but it works as long as it doesn't need much of UV penetration.

It works perfectly fine to light up watermarks.

 

[Ryanrpm]

And here is the most expensive one....probably out of your price range:

365nm with 3xAAA by Sunlite. Good quality lights though.

 

[yalskey]

I did a review on Amazon for this one...

http://www.amazon.com/gp/product/B0009JVQE6/?tag=cpf0b6-20

Check it out. Hope that helps.

 

[Glock27]

8 LED AA-powered UV Flashlight Item Id: CH8LEDUVAA_FL $6.99

http://www.lighthound.com/8-LED-AA-powered-UV-Flashlight_p_57.html

I got one of these for checking currency. Not real powerful, but does what I need it to.
G27

 

[RyanA]

And here is the most expensive one....probably out of your price range:

365nm with 3xAAA by Sunlite. Good quality lights though.

Man I really like the look of that one!:thumbsup:

 

[Antares]

Thanks for the feedback everyone.

@niner, Thanks for the feedback on that particular light, lucky for me to get a reply from someone who has it. I have no immediate plans to do any curing, I'm mostly interested in making things fluoresce. Sounds like it would be reasonably effective for that. Any idea at what range it would be effective at making things fluoresce, in a dark room?

I have to admit, I'm not too familiar with flashlight technology. Does direct-drive mean that it isn't regulated and output will not be consistent throughout the life of the batteries? I know what the emitters are, but I don't know what it means that they're parallel. Is 100ma a measurement of the output intensity?


@Ryanrpm, Yeah, that's probably more than I want to spend. The Streamlight Stylus UV is similar (at least superficially) and is a fraction of the price. If the Streamlight is really 365nm, is there something that would make the Sunlite superior enough to justify the much higher price? Is the output more intense?


@yalskey, Yeah, I'd actually seen your review before I even posted here. The dual wavelengths is nice, but like you I wish it was smaller.


@Glock27, Thanks for the link. Like many lights that one doesn't state the wavelength, which I always assume means >= 390nm.

 

[Ryanrpm]

@Ryanrpm, Yeah, that's probably more than I want to spend. The Streamlight Stylus UV is similar (at least superficially) and is a fraction of the price. If the Streamlight is really 365nm, is there something that would make the Sunlite superior enough to justify the much higher price? Is the output more intense?

Well, I took your question to the manufacturer of Sunlite products, and this is what they said:

From the technical aspect, I will add the following.

Streamlight UV chip is packaged in a traditional T-1 3/4 package.

The chip size is very small, only around 13x13 mil.
The chip structure is not designed for high power use, meaning heat cannot be removed away from the chip, therefore cannot be powered at high current.
The package is not designed for high power use. Heat generated from the LED chip becomes trapped, and the temperature of the LED chip will rise to over 125 degree C in only a few seconds. The UV light therefore will shift to a longer wavelength of over 400 nm.
In addition, the epoxy encapsulation turns yellow after exposed to the UV light, the light therefore degrades over time.

Our Slim UV LED light (365 nm) uses a Power UV LED chip 40X40 mil. The flip-over chip structure allows heat quickly removed from the LED chip itself. The LED chip is directly alloyed onto the copper housing, so the heat generated from the chip is efficiently drained to the heatsink. As a result, the temperature of the LED chip stays nearly the same as that of the LED head. Our 365nm UV LED is powered at 2 watt. We use glass lens to prevent yellowing and degradation.


I posted your question on their message board. You can view it here.

 

[tsask]

I EDC a UV AAA Arc on my keys. It is not as bright as I would have expected, yet it does work very well.
The build quality is superb, of course.

 

[Antares]

Well, I took your question to the manufacturer of Sunlite products, and this is what they said

Wow, thanks. I thought you might know just off the top of your head, but thanks for looking into it.

@tsask, Thanks for the feedback. I'd consider checking one of those out, but I guess availability is pretty hit or miss? When I was looking around at different lights I'm pretty sure the Arc website said they were in stock at the time and I didn't realize that it was a total fluke that they were available at the time I happened to be looking and would sell out in short order.

 

[Ryanrpm]

LOL.....well, on their forum I did mention my thoughts, but I knew they would know more technical info as to its superiority over the Streamlight.

The things that come to my mind, are the lifetime warranty, the build quality, 2w of output, runtime, quality of light emission, and interchangeability with other Sunlite LED heads.

Have you landed on one yet?

 

[Antares]

Yeah, those comments are interesting. I'm not sure if the person who posted that is an employee of the company or what?

I doubt I'm going to end up spending the money on the Sunlite at this point, but perhaps I don't want the Streamlight either. Even though the Streamlight is a fraction of the cost, if it's actually going to produce 400nm plus (as seems to be suggested in the post on the Sunlite forum) rather than 365nm, I wouldn't consider it to be an appealing option or a good value for me. I'd think that if it was producing 400nm plus that would be pretty obvious based on the amount of visible light. I guess I need more information.

2W isn't actually a measure of the intensity of the output, correct? My understanding is that 2W is the amount of power driving (not sure if that's the correct term) the LED.

Do you happen to own a UV Sunlite?

I haven't purchased anything yet. If I'd realized how limited their availability is, I probably would have bought an Arc when they were available. If I liked it, great. If not, I assume the resale value would be pretty good since the supply seems scarce. I may give that 5 x Nichia 365nm model from LED Wholesalers a shot. Not sure yet.

 

[parnass]

Another option is to buy a UV flashlight from Peak LED Solutions. They have a 25% off sale until the end of March.

 

[Antares]

Thanks for the suggestion. However, according to Choosing a Peak LED Solutions Flashlight (PDF) their UV lights are 395nm.

 

[Luke_Y]

Thanks for the feedback everyone.

@niner, Thanks for the feedback on that particular light, lucky for me to get a reply from someone who has it. I have no immediate plans to do any curing, I'm mostly interested in making things fluoresce. Sounds like it would be reasonably effective for that. Any idea at what range it would be effective at making things fluoresce, in a dark room?

I may be able to help. What sort of things are you trying to fluoresce? Different substances have different optimal wavelengths. Allot of substances fluoresce with long wave uv.

Long wave uv lights are plentiful as you are finding. But, short wave uv <280nm lights are more scarce. If you end up in the short wave end use caution. These lights can be detrimental to your eyesight.

If you are already well versed, sorry, just disregard.

 

[Antares]

Thanks Luke_Y. I certainly don't claim to be an expert on this stuff, but I know what you mean. I'm definitely looking for a long wave light, but I want the shortest wavelength (closing in on 360nm-365nm) that I can get. It's my understanding that a considerable amount of caution is appropriate even with the long wave lights.

 

[HKJ]

The Sunlite is a good UV light, here are some examples on different UV lights with a Swedish 100Kr note:

First a white led:

Next up is the Inova X5 with 5 UV leds, it is possible to see the hidden text:

The ARC-UV is much better (375nm):

And the Sunlite 365nm:

Edit:
All the pictures are with the same camera setting and the UV lights at the same position.

 

[Antares]

Wow, those pictures are awesome! Thanks so much for posting those, they are really helpful.

How accurately do the Arc and Sunlite pictures represent what you see with the naked eye? The Arc picture makes it seem like it does a good job of fluorescing the text while the rest of the note in the background remains dark and barely visible. The Sunlite picture makes it seem like it does an even better job of fluorescing the text, but the rest of the note in the background is clearly visible. Is the Sunlite actually generating visible light that makes the background visible, or is that just something the camera is picking up?

Thanks!

 

[HKJ]

Wow, those pictures are awesome! Thanks so much for posting those, they are really helpful.

How accurately do the Arc and Sunlite pictures represent what you see with the naked eye? The Arc picture makes it seem like it does a good job of fluorescing the text while the rest of the note in the background remains dark and barely visible. The Sunlite picture makes it seem like it does an even better job of fluorescing the text, but the rest of the note in the background is clearly visible. Is the Sunlite actually generating visible light that makes the background visible, or is that just something the camera is picking up?

They are close to what I see.

When I received the Sunlite I turned it on and saw some white light, my first reaction was that I had got a ordinary light (but a bit weak), not an UV light. But my test with the Swedish bank note convinced me otherwise.:thumbsup:
The ARC light also has visible light, but not as strong (To week for the camera to pick up with the settings I used) and much more blue.

 

[Antares]

Huh, that is really interesting. I wouldn't expect a 365nm light to generate that much visible light. The one demo picture that Sunlite has on their website for the Slim UV gave me the impression that it was generating quite a bit of visible light, but given the overall awful quality of that image file I didn't take it for granted that the apparent amount of visible light was an accurate representation. It's also my understanding that a digital camera may make some UV light appear to be visible light. Based on your photos, the Sunlite does seem to do the best job of fluorescing the text, but I'm surprised at the amount of visible light.