Just another cheap Photon-II knockoff....?

[Chris M.]

Looks ordinary enough doesn`t it? OK so there`s a rather handy finger-clip that can be fitted in place of the keychain, but there is a bigger surprise in store when you turn the thing on!

Two colours! Yes, it is only a single, ordinary looking 5mm LED that is usually at home poking out of the front of these lights, but the real magic is inside.

Two diecups, two different dies! Excuse the fuzzy shots please, it`s hard taking pictures of the innards of LEDs. You can hopefully just make out the fact that they are connected in series by the gold bond-wires. Each die is slightly oblong in shape and has two bond wires attached at the "middles" instead of the more common opposing corner attachment of this type of die. Power comes from two CR2016 cells, not sure how this works out as both dies appear to be Nitride type going by the colours (Vf ~3.6v), but it`s possible the green isn`t, and is just a deeper than usual shade of GaAlAs green.
They are avaliable in five colour combinations- Blue/red, Blue/green, Blue/yellow, Green/yellow and Gren/red. This bue/green one is not very bright unfortunately, can`t speak for other colours but looking at the auction foto they seem similar. So, asides from an interesting novelty I can`t see there being much of a serious flashlighting use for these.


I have no idea where these LEDs come from (probably Hong Kong), except that they are being sold on Ebay by a seller in the UK, user ID: [email protected]

Starting at GB£4.50 but unfortunately I just noticed they say UK only on the page. It won`t hurt to ask if they will sell overseas, should anyone be interested.

 

[hotfoot]

I'll betcha Craig is gonna want one of those LEDs for the musuem!

 

[TrevorNasko]

hotfoot- fetch boy fetch!

 

[The_LED_Museum]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Chris M.:
They are avaliable in five colour combinations- Blue/red, Blue/green, Blue/yellow, Green/yellow and Gren/red. This bue/green one is not very bright unfortunately, can`t speak for other colours but looking at the auction foto they seem similar. <HR></BLOCKQUOTE>

My guess is that the blue/green combo will be the dimmest ones of the lot, because of having two InGaN chips in series. The Vf (forward voltage) of the lamp will then exceed the open circuit voltage of the battery, which should be around 6 volts & change.

Blue/red = GaN + AlInGaP, Vf= approx. 5.6v
Blue/yellow = GaN + AlInGaP, Vf=approx. 5.7v
Blue/green = GaN + InGaN, Vf=approx. 7.0v
Green/red = InGaN + AlInGaP, Vf=approx. 5.4v
Green/yellow = InGaN + AlInGaP, Vf=approx. 5.6v

Lower Vf should result in a higher current consumption off the 6.0 source, and brighter LEDs initially. Higher Vf will result in dimmer LEDs but a longer battery life.

Your photo tells me the green emitter in your green/blue light is an InGaN on Al2O3 chip (520-530nm), rather than the original formula "emerald green" 550nm non-nitrogen-doped GaP chemistry. (N doping of GaP yellows the emission color substantially, making the LED color more like the yucky swampwater yellow-green backlight in your cell phone).

 

[Plinko]

Yeah, I was wondering how long it would take for someone else to discover these.

I have all the color combinations, and they seem to be fairly equal in brightness (which isn't up to much, as you've noticed). Since most people would be looking directly at the light source, rather than the light image (beam) that is projected, I filed down the outside of the LED so that it diffracts much more at the source and gives the deceptive appearance of being brighter. If you hang several of them together, like on a neck lanyard or such, it acts as sort of a poor man's Eternalight Ravn. I actually like them better because they're so much smaller and lighter than wearing a big ol' Eternalight strapped around yer neck.

Cheers!