This is another novel application of the new high powered violet LEDs just coming on the market.
This combination ballpoint pen and near-UV LED light is being sold for its ability to cause a UV-like fluorescence in a variety of materials such as postage stamps, credit cards, and paper money.
The LED in this pen is a new deep violet model emitting at between 390 and 410nm (typical peak 400nm) which is right at the border between violet and ultraviolet. Until recently, this LED was only
a laboratory curiosity, and before that (late 1990s), only a myth, like the Loch Ness Monster or Bigfoot.
The pen comes ready to use right out of the package.
To turn it on, press the small button on the pen barrel, quit pushing to shut it off.
The main use for a light like this is to check official documents for forgery. The paper money in many countries has anti-counterfeiting measures built into it that will glow
when this light is used on it. In US money, it is a stripe embedded in the bills.
Some postage stamps also have similar technology; see the pictures below for an example of this found on Hong Kong postage.
It has also been said that some types of credit cards have a hidden picture on them which will become visible under the light from this flashlight; however since I've never
had a credit card, I am not equipped to test or verify this.
This light uses four tiny LR41 button cells. Hopefully, you'll be able to find these at your local pharmacy or a known battery source like Radio Shack.
To change them, grasp the pen with one hand on each side of the gold band in the center, and twist it counterclockwise. It will unscrew, and seperate into two pieces.
The batteries are in the top portion. Dump out the old ones, and insert four new batteries, flat side (-) facing you.
Screw the two halves back together, and be done with it.
The pen / flashlight unit is not water resistant, so a concerted effort should be made to keep it from falling in the toilet or drowing under your lawn sprinkler. If water does get in, just open it up and
dry out all the parts, and it should be fine.
The pen portion seems to be on par with any of the less expensive disposables available, and it writes with blue ink.
The pen cartridge is replaceable by pulling the two pieces of the lower barrel straight apart, and unscrewing the cartridge by turning the black knurled piece on it.
I am not familiar with this cartridge type though, so I can't tell you where to get replacements or what kind to ask for.
Best bet is to just bring the cartridge with you to a large office supply depot, and start checking all the pen cartridges on the shelf until you come to one that looks the same. :-O
The overall construction is not exactly super high quality, but then again this isn't a $50 Parker or a $5,000 Mount Blanc.
What makes this pen / LED light combo worth having though is that LED. Nobody else is making a flashlight or other portable source with a 390-410nm near-UV LED.
If this device has a saving grace, this is definitely it.
The LED used in this light causes fluorescence (glowing) in a number of different materials. Brightly colored plastic, some types of markings or bar codes left on mail by the
post office, orange traffic cones, brightly colored price stickers, and "blacklight" posters are some of the things that will glow brightly.
The light also makes old pee-pee glow, so it can be used to check garments or bedsheets for evidence of urination; however
this only works if the fabric itself does not also glow. It can be used on some carpets & rugs to check for dog pee, so you can clean & deodorize that spot so Fido will be less likely
to "re-offend" in the same place. The longer wavelength of this pen does limit its use for locating "waste", though it still works fine for checking money & documents.
The use for which this light is marketed however, is to check paper money and other official documents for counterfeiting. Newer US money has a strip embedded in it which
usually glows under longwave UV. I say "usually" because sometimes this glow is lost if the bill goes through the washing machine once or twice. The strip can still be viewed
using a pass-through detection method though.
Other official documents are sometimes treated with UV sensitive materials. Some postage stamps have glow strips that show up
under this flashlight, and some business checks (and a few personal type checks) have fibers that light up a brilliant greenish white in this flashlight's deep purple light. Tickets
for official events like baseball and football games often have a pattern on the back that only becomes visible when you shine a light like this at them.
Try shining it at your TV set or computer monitor (when they are off) and see if you notice a greenish white glow on the screen.
Try it on glow-in-the-dark watch or clock hands.
Try it on different kinds of white paper. Some kinds glow bright sky blue, others just show a dull purple.
Greenish colored antifreeze fluid should glow brightly under this flashlight (not tested, as I don't have a car)
Some species of scorpions indigenous to the southwestern US will glow a whitish green.
Some types of mushrooms, toadstools, mould and other fungi may also glow under this light. I found some in the soil of a potted plant that was not visible in ordinary light.
Just experiment... you'll find a lot of stuff that glows all funny, and maybe find something quite unexpected.
Invisible bar code marker left on a Christmas card that went through the mail.
Deep purple, medium-angle beam from approx. 1 foot away
The camera renders the deep purple glow as a blue color; in reality it looks like dark royal purple.
May be too short in wavelength to be analyzed further with the equipment at my disposal.
Test unit was received on 12-27-01, and is in the queue for being tested, bashed and thrashed.
I have somewhat of a backlog here, but I'm trying to fit everything in a bit at a time so nobody gets left out for too long.
The LED used in this light is not a Cree product, but is supposedly being made by another US manufacturer.
Wavelength appears to be close to 400nm.
CAUTION: The light emitted by this product is right on the border between visible and UV, and there will be smaller levels of radiation that clearly falls into the long UVA range.
Therefore, you should not shine this light directly into your eyes for any amount of time beyond a single blast of 1 or 2 seconds on any given day.
Although not as likely as it might be with a shorter wave source like the Nichia LED or mercury vapor suntan lamps, it is still possible to damage your eyes with prolonged
viewing of the direct beam (putting the flashlight up to your eye and letting it cook there). Signs of UV exposure include a burning or "sand in the eyes" sensation, and
a hazy look around light bulbs or other light sources. Symptoms of UVA exposure may take
an hour or two to develop following exposure. Mild cases are typically self-correcting within 24-36 hours; if you have anything more than mild symptoms, call your eye doctor
right away, and bring the light with you so he will know what he's dealing with. Tell him the "peak wavelength" is right around 390 nanometers, and let that be a lesson learned.
MANUFACTURER: Wilycon LTD
PRODUCT TYPE: Ballpoint pen / LED flashlight combo
LAMP TYPE: LED, Deep violet, 5mm
No. OF LAMPS: 1
BEAM TYPE: Medium angle with central hotspot and wider corona
SWITCH TYPE: Momentary pushbutton on/off
BATTERY: 4 LR41 alkaline button cells
CURRENT CONSUMPTION: Not yet measured
WATER RESISTANT: No
WARRANTY: Not stated
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