9xLED 385nm UV FLASHLIGHT

9xLED 385nm UV Flashlight, retail $14.00
Manufactured by (Unknown)
Last updated 09-25-08




This is a small (handheld) source of UVA (ultraviolet type A or "longwave UV") radiation. It comes in an almost all-aluminum body, has 9 UVA LEDs in its end, and is powered by three AAA cells held in a side-by-side carriage in its barrel to hep keep the length down.

The dominant wavelength (where you would point to on a color chart) appears to be approximately 389nm; which is in the long ultraviolet/ super deep violet part of the spectrum. The advertised wavelength is 385nm, so it's a pleasant surprise to see advertised vs. measured wavelengths being so close to one another.


SIZE



To use the 9xLED 385nm UV Flashlight, feed it first (see below), and then you can go to town.

Press the black tailcap button firmly until it clicks and then release it to turn the light on.
Repeat the same action to turn it off.

There is no momentary or signalling mode available when the flashlight is off, however, you can blink the 9xLED 385nm UV Flashlight while it is on by partially depressing the tailcap button. If you don't mind the backward or reverse feeling of this, you can blink the light this way.



To change the batteries in your 9xLED 385nm UV Flashlight, unscrew and remove the tailcap, dash it to the ground, and stomp on it with old or used bowling shoes...O WAIT!!! YOU'LL NEED THAT!!! So just set it aside instead.

Tip the white plastic battery carriage out of the barrel and into your hand. If necessary, remove and dispose of or recycle the used cells if they are present in this carriage.

Insert three new AAA cells into the carriage, one in each compartment. Orient each cell so the flat-end (-) negative faces a spring for it in its compartment.

Once the carriage is full, insert it into the flashlight's barrel, aiming it so the end with the larger piece of brass on it goes in first. Screw the tailcap back on, and be done with it.
Aren't you glad you didn't stomp on that tailcap now?

Current usage measures 141.7mA on my DMM's 400mA scale.
This equates to a drive current of ~15.74mA per LED.



This flashlight is reasonably durable, but could become broken if violently thrown against a hard surface, stepped on with hard-soled shoes, or run over with a motor vehicle - although ordinary flashlight accidents should not be enough to do it in. I administered the smack test on it (ten whacks against the concrete floor of a porch; five whacks against the side of the tailcap and five whacks against the side of the bezel), and found only some minor gouging to the bare Metalmegaseadramon - er - bare Metalstingmon - um that's not it either...bare Metalarukenimon...ummm that's not it either...bare Metalmalomyotismon...er...uh wait a sec here...BARE METAL (guess I've been watching too much Digimon again! - now I'm just making {vulgar term for poo-poo} up!!!) was seen on the sides of the bezel and tailcap where it was struck.
No optical or electrical malfunctions were detected.

It is splash resistant and weather resistant, but it is not waterproof or submersible. I removed the tailcap, relieved the light of batteries, and suctioned it; and a small amount of air got in. So please try to keep it away from creeks, rivers, ponds, lakes, puddles of donkey pee, snowbanks, water-filled ditches, sinks, tubs, toilets, fishtanks, dog water dishes, or other places where water or water-like liquids might be found. If you know or suspect it got dredged, take the tailcap and bezel off, relieve it of its batteries, and set it in a warm, dry place for a day or so, and you ought to be in good shape.
If it fell in seawater or if somebody or something peed on it, douche all the parts in fresh water before setting them out to dry.
It should be OK to use in rain or snow, but I cannot verify this firsthand - it's very early autumn here in Sacramento CA. USA and rain isn't forecast for at least the immediate future. But judging solely by the results of "The Suction Test", it should fare rather well in inclement weather.

This light isn't meant to be used like an ordinary flashlight; its intended use is activating fluorescent materials like the security strips in US paper currency, security markings on some types of postage stamps, security markings on event tickets, security features on ID cards & bank cards, some types of scorpions indigenous to the southwestern United States, defects or repairs made to antique glass articles, and similar.

The UVA output of ~389nm is shorter in wavelength than what is normally found in "money checkers" or other UV flashlights, so its output will appear dimmer to the eye. But don't let that sickly, weak purple glow fool you. Please do not shine it in your eyes, other people's eyes, or pet's eyes. This light emits copious amounts of UVA (longwave ultraviolet) radiation, and that isn't very good for the eyes if stared directly into.

The LED bodies themselves glow dimly with a bluish violet color. I don't know if this is accidental fluorescence or purposeful fluorescence; and I do not know who makes the LEDs either. These LEDs have a dual-bond construction, so I know right away they aren't Cree parts. Whoever makes 385nm LEDs with a dual-bond construction with the die wires attaching at each end of the die (light emitting chip) inside each LED is responsible for these. Could be Uniroyal or Toyoda Gosei.

These LEDs typically have short device halflives; one tester reports getting under 200 hours to half-intensity at normal drive currents (20mA typical) for UVA LEDs in epoxy bodies, like these.



Beam photograph on the test target at 12".



Photograph of security features of an ID card and a bank card fluorescing (glowing).

I will not have photographs of the security strip in US paper currency fluorescing
for another 7 to 10 days, because I have no money at the moment.


Spectrographic plot
Spectrographic analysis of the LEDs in this flashlight.
USB2000 spectrometer graciously donated by P.L.








TEST NOTES:
Test unit was purchased on Ebay on 09-18-08 (paid for w/ Paypal!), and was received on the afternoon of 09-20-08.

Product was made in China.
A product's country of origin really does matter to some people, which is why I published it on this web page.

The advertised wavelength and the measured wavelength (measured via spectroscopy) are actually very close to one another - something not often seen in products like this with emitted wavelengths much shorter than ~400nm.

Usually, something advertised as being 385nm measures more like 400nm or even 405nm - and it really *DOES* make a difference at wavelengths this short.


UPDATE: 00-00-00



PROS:



CONS:



    MANUFACTURER: Unknown
    PRODUCT TYPE: Portable UVA radiation source
    LAMP TYPE: 5mm UVA LED
    No. OF LAMPS: 9
    BEAM TYPE: Medium spot w/ dim corona
    SWITCH TYPE: Pushbutton on/off on tailcap
    CASE MATERIAL: Aluminum
    BEZEL: Metal; LEDs protected by plastic window
    BATTERY: 3xAAA cells
    CURRENT CONSUMPTION: 141.7mA
    WATER RESISTANT: Yes; weather-resistant at minimum
    SUBMERSIBLE: No
    ACCESSORIES: Small lanyard
    WARRANTY: Unknown/not stated

    PRODUCT RATING:

    Star Rating





9xLED 385nm UV Flashlight *






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