Jaxman U1

I bought this light from Tinywind.
The Jaxman U1 comes in a simple white cardboard box, containing the light, 2 spare orings and a lanyard.

Please remember that UV lights are not toys and must be used with responsibilty.

The cheap widely available UV LED lights orund the shops have many 5 mm leds, work with 3AAA cells, have no circuit or regulation and are poorly constructed.
This is another kind of light, as you will see in this review.


Producer's spec:High Quality UV Violet LED Bulb
Water & Scratch resistance glass lens
Reverse Polarity Protection
Durable aluminum textured reflector
High efficiency UV optical power, up to 780 mw.
Special Glass allow UV pass with double Side AR Coating Lens
Pls wear Anti-UV glasses when using U1 flashlight!
Specifications:
Brand: JAXMAN
Model: U1
Body Material: Aluminum Alloy, with oxide coating >45 um
Emitter Type: 365nm UV led made in China
Battery Configuration: 1 x 4.2V 18650 battery (Not Included)
Switch: Tail Cap Clicky
Size: 117mm x 22mm
Weight:80g
The light has just 1 mode at 700mA (I measured 0.67A).


The U1, here in all its simplicity





The U1 doesn't have any flaw in the machining or lettering.



The threads on the tailcap are anodized and allow lockout. The o-rings are thick and should ensure a certain water resistance. On the body of the light there is some knurling, well done, offers medium grip (it could be more aggressive).



The inside of the tailcap, all metal here



The U1 can tailstand. It has 2 holes for the lanyard.



The glass doesn't allow to see what's inside the U1 head.

This is no surprise because it was chosed a glass very transparent at the UV light, but not transparent to visible light. This allows to maximize the UV effect.
Even frontally, only reflexes.






The inside of the head: the circiuit is labeled Jaxman, with golden spring.



The U1 works with button top and flat top 18650 cells, thanks to the spring at the positive pole. There's no reverse polarity protection, so be careful.
When the U1 is on, it doesn't seem so. If you point it at a white wall you might see 0,5 lumen of violet light. this is good, it means that the output in the visibile range is limited.
But when it gets closer to something UV reactive... that's a different story :naughty: (pics taken at ISO 200).






Here I moved the U1: it works well even if it isn't pointed directly to some object.




Other setup








I enjoyed looking around for things that I found interesting, as a metal doorknob with a lot of scartches.



A doorphone.



A black pullover, the white fibers are invisible to naekd eye, and come from wearing a labcoat.



The paper money test is a good test, here you can see both the output (i.e. lumen) and the wavelenght differces: the U1 has its peak at 365 nm, while many other cheap lights have their peack "around 395 nm". If you try with paper money, you will see many details, that are invisibile to cheap lights, no metter how close the light is to the paper.


I couldn't make a runtime test because the luxmeters usually works in the Visible wavelenght, and this light has about none in this spectra. Given the small current required (0,7A) and the great capacity of the 18650s, I'd say that the runtime isn't a problem.

I like this light a lot. It is nice looking and well built, works with 18650, and has a great UV performance.:twothumbs
Thanks for reading.

Nice review. I got one too. That uv filter makes ALL the difference!

I missed the filter part. Can one of y'all explain that a little more?
Neat review. You don't see many UV reviews. :kiss:

What is the color of the light coming from an ideal UV lamp? Black (no light).
An ideal UV light will have emission only inside the UV spectra.
A cheap UV light is far away from the ideal UV light, so, as well as emitting in the UV spectra, it will emit in the visible (tipically purple)

What does this mean in practice?
This is money paper with a cheap UV light, that has a lot of its output in the visible, and a small part in the UV. You can tell because everything is purple, and you will se inside the whole purple item some portions that are UV reactive.



This pic uses a light that uses a stronger emitter (more W) and more selective toward the UV light: you can see that a diffuse fluorescence (it is not the blu coming from the light, it's the natural fluorescence of a lot of object as paper that are bluish), and a STRONG fluorescence of the items that are UV reactive. In the paper money this items are strands of UV reactive fiber casually disperded inside the tissue. Notice how the background has almost no fluorescence, and it does not reflect any visible light, because from the light there is no output in the visible wavelenght.


You can say: but I can get the same picture if I use 100 emitters from the first picture, all toghether. NO, because you will still have a lot of issue detecting the UV reactive items inside a 100 times stronger Purple colour

The lesser a UV light emits in the visible, the easier is for your eye to detect fluorescence, and you can get this by using a good UV emitter that has a low emission in the visible, and add a special filtered glass that allows the passage of the UV and blocks most of the visible light.
With the U1, both choices were made, assuring a very good result.

Sorry for the bad english.

The Jaxman U1 uses a ZWB2 UV bandpass filter to eliminate the blue light the UV LED also emits. It's peak transmittance is about 85% at roughly 365nm. A quick google search turns up this transmittance curve:



EDIT: Credit goes to djozz @ BLF for turning me on to this filter.

I just buy Jaxman U1 with Nichia LED - 52$ free shipping. Now, anybody has any clue how can I check if indeed is Nichia led and not the chinese version. On the order was the correct number but I want to be sure that the seller didn't trick me and took extra 20$. I cannot remove the led. Any ideas how can I tell if is Nichia or not???

Where can you get quality UV protective goggles?