Review of Jaxman U1 365 nm

I bought this light from Tinywind with the groupbuy organized on this forum.
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.
Thanks for reading.

Thanks for the review.
These new power UV lights have my interest but I’m concerned about eye damage from prolonged use even from indirect exposure.

Great pics btw, just curious did u happen to have any slight eye strain after use?

Your comment is right.
I use everyday at work a 5W UV 254 nm / 360nm neon lamp, and the proucer gives you a small box with a filtered window so you can observe what happens inside without any risk.
I wear eye glasses, and glass it is not UV transparent: if you spend your time inside the car or at the window with the windows closed, you will get almost no tanning.
Knowing this, I checked the transparency of my glasses with an empiric method: I put the glasses in front of the light and there was no UV output (no fluorescence effect like the one shown in all the pics).
However, I didn’t mess around at close distances, and there were no reflecting surfaces inside the room.
I didn’t have any problem with my eyes after, but I was quite careful.

If you not wear glasses, I suggest you to wear one when using the light in a reflective or partially reflective environmental.

hmmm…

i am thankful for the review - but the eye-damage thing makes me worry a bit….
i was not aware of a big risk (besides not to look into the emitter directly of via a mirror…)

can you explain a bit of potential issues with the UV in this/a flashlight?

It is like the sun: never stare it because it damages your eyes. This time, if you look inside the emitter, your body will not have the instinct of closing the eyes because it is calibrated on the visible wavelenght.

If you plan to use it for a few minutes every once in a while I think it’s ok, but if you use it for long periods of time I’ll suggest to wear protective glasses… But I’m not a Medical Doctor.

Even your skin is very sensitive to UV light, it produces a dark pigment in order to protect itself, and if is too much damaged, the cells will kill themself by apoptosys to prevent skin cancer.
Thus said, I have seen pictures of people taken with uv light for science, and I think that a small controlled exposure of healthy skin should ok.
But again, I’m not a MD.

Thanks for the review! :-)

I have done a fair amount of tests with 365-400nm leds, in- and outside flashlights and I can tell you that despite quite consistently wearing safety glasses, at the end of such an evening I can feel in my eyes that they have suffered some uv-impact. I have the idea that this is temporary, the next day it feels normal again. Btw, a direct hit in the eye with 365nm I feel immediately on the retina, very very unpleasant, enough to look away fast.

You can never be sure, but as far as I can notice, there's no sign of permanent eye damage (yet)

About skin damage, 365nm light has pretty low impact on your skin, if any. It is the shorter wavelength UV in the sun that does the real damage.

Edit: one research on hai-rless mice concluded that 365nm light is carcinogenic, but 10000 times less than 293nm (the most carcinogenic wavelength for hair-less mice)

Thanks for the review Budda. The pictures are real nice and show the UV perfectly.

Thanks for the informative comments and unfortunately I don’t wear glasses so no protection for my eyes. Going with my better judgment I will just enjoy these High power UV lights from posts n pics on the forum.
I do however have a 5mm Nichia UV LED 375nm that does a great job at lighting up all the marks on money bills and can cure Norland pretty quickly. It is the Arc AAA UV and is very dim (very little visible light) but if I ever need to check for real money or real urine on the carpet it does the job while keeping me safe. :bigsmile:
Thanks again for the review and the awesome pics!

Thanks for the review. Since I don’t have any 18650 batteries, I ordered the E3 (aaa) version, will be very interested to see the difference!