(Rec'd 07-31-08, tested 08-01-08)
This is one of three LEDs sold as "InspirationLEDs" by Lumex. Although this might look like an ordinary 5mm clear through-hole LED, it differs from all others because it is phosphor-based, and more importantly, it emits a TURQUOISE light, not white, yellow, pink, or purple like other phosphor LEDs available today (early-August 2008).
Here's what the actual LED looks like.
In this photograph, it is energised and receiving just under 2mA in my LED test set.
I've never before seen a phosphor turquoise LED, so imagine my surprise when I saw an ad in Laser Focus World magazine for InspirationLEDs that included this lamp!!!
Needless to say, I wasted no time in contacting Lumex for samples of this lamp plus the other two lamps in the InspirationLEDs line.
It emits a turquoise (blue-green) light, and it has a beam pattern that's smoother in general profile than any non-phosphor blue-green LED - but I rather expected this from a phosphor lamp.
Beam photograph on the test target at 12".
Intensity measures 5,500mcd at an If of 19.28mA. Vf is 3.094 volts.
Spectrographic analysis of this LED, using newer spectrometer software.
Spectrographic analysis of this LED at 19.28mA.
Spectrographic analysis of this LED at ~1.95mA.
3mm "Ocean Green" LED, origin unknown
(Rec'd 01-06-06, tested 01-20-06)
A fan of the website sent me a number of different LEDs; and 2 of these LEDs were among the goodies.
These are labelled as "Ocean Green" LEDs, which emit at 505-507nm in the blue-green region of the spectrum. These are a bit greener than the "Tokyo Blue" blue-green LEDs that used to be more common. This is perfectly normal, and does not in any way indicate a problem with the LED. See the text for the Nichia NSPE500S LED farther down this web page for a bit more explanation. These LEDs are bluer than true green InGaN LEDs, and greener than true blue GaN LEDs.
The LED has a dual-bond construction; I don't know who actually manufactured it.
At a test current of 19.28mA, intensity was measured at 5,680mcd.
Vf was measured at 3.195 volts.
I'm not equipped to measure beam angles at all. Looks like about 35 degrees to me.
Cree SMD Blue-Green LED
(Rec'd in early 2003, tested 12-05-04)
A fan of the website send me this LED in early-2003, already affixed to a piece of breadboard and outfitted with a resistor, reverse-polarity protection diode, and a 9V battery connector. I somehow managed to lose or misplace it, but it turned up on 11-18-04 while I was looking through boxes following a move I made on 10-11-04.
Here are a couple of photographs:
The photograph on the left shows the LED illuminated, and the one on the right shows it compared in size to a 5mm through-hole LED.
Tested on a Duracell 9 volt battery that measures 8.28 volts open-circuit.
The approximate dominant wavelength (where you would point to on a colour chart) is 507nm, which is considered to be "traffic signal green".
The sender of this LED wrote the following:
I got it from ETG. Model unknown. The die sure looks like a Cree - unknown series. Size I believe 0603. Possibly in ETG's website, or possibly an older version of something in their website...
Look at: http://www.etgtech.com/pdf/ETG-0603.pdf.
It may be an ETG-0603CE505-130 or some older version with a similar part number.
Chi Wing 5mm "Ocean Green" LED, (http://stores.ebay.com/chiwingledproductshop)
(Rec'd 12-24-2003, tested 12-25-2003)
A fan of the website sent me a box of goodies (like batteries, LEDs, flashlights, and a laser); and 5 of these LEDs were among the goodies.
These are Chi Wing's "Ocean Green" LEDs, which emit at 505-507nm in the blue-green region of the spectrum. These are a bit greener than the "Tokyo Blue" blue-green LEDs that used to be more common. This is perfectly normal, and does not in any way indicate a problem with the LED. See the text for the LED directly below for a bit more explanation. These LEDs are bluer than true green InGaN LEDs, and greener than true blue GaN LEDs.
The LED has a dual-bond construction; I don't know who actually manufactured it.
At a test current of 23mA, intensity is measured at 14,370mcd.
I'm not equipped to measure beam angles at all. Looks like about 20 degrees to me.
Spectrographic analysis of this LED.
Nichia America, part # NSPE500S, 5mm round, 15°
(Received 11-03-03, tested 11-04-03)
Yesterday, I received an envelope from Nichia, and in it were several LEDs and a small flashlight. Here is one of those LEDs, the blue-green NSPE500S, a 5mm LED in a standard, water-clear epoxy package.
When illuminated, the LED appears to have a slightly greener color than is typical for a blue-green LED. My spectrometer is broken, so I'll have to "eyeball" it...yup, it's greener alright. Looks to be close to 505nm, which is right near the greener end of the wavelength range for these LEDs. But there's nothing whatsoever wrong with the LED, don't get me wrong here. It's just a bit more greenish than usual for a blue-green LED. Brightness should be 9,200mcd at a drive current of 20mA.
A fan of the website - someone who's work I trust - emailed me last night (11-04-03) with additional info regarding this and other blue-green LEDs. I don't have room on the server to put his whole email here, but the crux of the matter is that manufacturers of blue-green LEDs are trying to produce these on the greener side of blue-green, rather than having them greener by accident. The older style "Tokyo blue" (490-500nm) blue-green LEDs are less favoured by traffic light manufacturers than these more greenish (505-510nm) models. These greener LEDs emit closer to the photopic peak of human vision than the older bluish versions do, so that green traffic signals made with these LEDs are more easily visible. Yet they'll still emit enough blue to be visible to somebody with red/green color blindness.
This LED is a Rank IE3 part, which according to the catalogue that was included, has a peak wavelength of 505-510nm. The wavelength determinator is the "E" part. I'm not sure what the other two characters are just yet.
Test current 26mA, Vf=3.48 volts
Used the LED Tester from Hosfelt Electronics.
Brightness is measured at 19,800mcd using a Meterman LM631 light meter.
AXT Optoelectronics, part # LE505-C2-E, 5mm round, 15°, price/availability not known
I've had a lot of stuff delivered here by UPS, USPS, Federal Express, and a few other carriers over the last couple of years. They all wait downstairs and ring the bell and never show up before ten O'clock. So this morning when DHL Couriers got my butt out of bed at 9 with their insistent knock-knock-knock on the door, I was quite surprised.
In a small box arrived samples of InGaN LED lamps made by AXT Optoelectronics out of California. This LED is one of three types that were sent. Packaged in the familiar round 5mm water-clear case, it looks a lot like any other blue-green LED. And it has the same color range. But this LED is different: it has a smoother than usual, sharply defined round beam with little waste off to the sides.
The beam from this LED is projected in a neatly confined, 15° circle without those annoying rings & die images often found in this type of LED. For the above picture, the LED was place 24" from the target, as it will be when I run it through the ProMetric System later today. It will of course be aligned to the screen just a bit better, so it may appear a bit less "out of round" than it does in this quick snapshot.
Published wavelength of this batch is 505nm and published power output is a couple of milliwatts (this will be measured later as well). An initial illuminance reading showed the intensity to be 8,500mcd.
To the eye, this particular sample appears to be between 505 and 507nm. As time permits, it will be compared with additional samples that were included so that I may check for color & beam quality consistency within the batch.
Photometric charts were made using the ProMetric System, on loan from Radiant Imaging.
AXT also generously provided samples of their 470nm blue and 525nm green GaN and InGaN LEDs along with these blue-green lamps. They will appear on their respective pages as time permits.
Toyoda Gosei, part E1L53-NC, price/availability not known
This is a blue-green LED made by Toyoda Gosei, a company competing with Nichia in the gallium nitride LED wars. This sample dates back a couple of years, so newer models will likely be substantially brighter.
The LED comes in a standard 5mm package with a water-clear lens, and has a dominant wavelength (the place on the spectrum you would point to) of approximately 507nm, which is just slightly more greenish than is typical for blue-green LEDs.
Brightness measured at 4,500mcd in a 45° beam with 30mA of drive current.
Color is slightly but noticeably more greenish than is shown in this picture.
Like other blue-green LEDs, this one has a substantial red-shift at lowered currents; becoming quite green by the time you're nearing 1 or 2 milliamps.
I do not know who stocks this part, but you may be able to obtain them directly from Toyoda Gosei if you're lucky or hit on the right salesperson.
Nichia America, part NSPE595BS, $8.00 apiece through Nichia America
If you want really unusual colors in your LEDs, this one is for you.
Red, orange, yellow, green and blue LEDs have been available in some form for at least 20 years (about 10 for blue), but not until the last year or so (this text was written in 1999) have turquoise LEDs become available to the general public and to private hobbyists & experimentors.
This is a very bright LED that appears to be a Nichia NSPE series, with a very unusual, radiant color. It is also highly visible at night. One company capitalised on this and started selling miniature flashlights using these Nichia turquoise LEDs. That's where I got mine.
The color is almost indescribable - no natural or artificial light source other than very expensive lasers has produced this wavelength until now. Its brightness is almost shocking, when you consider how tiny that little chip inside really is. Since I've put the LED back in my Photon Micro Light flashlight where it belongs, I don't have a whole lot of information or test results to give on it - other than find one for yourself and be amazed.
UPDATE 10-24-99: This LED turns very greenish when run at lower current. Much as the nitride-based green LEDs turn yellow under these conditions, these turquoise LEDs lose a substantial amount of their output in the blue region, and appear much greener than they normally do. Not just a little, either. It's a really dramatic change.
Beam profile of this LED.
Nichia America, part NPSE590S, $8.00 apiece (old model may be much less expensive)
Here's a very narrow-beam, very brilliant turquoise LED for you to muse over.
Packaged in a water-clear T1 3/4 case, this little dazzler could leave you seeing spots. This LED has one of the narrowest, most well-defined beams I've seen in an LED. When shone at a wall at any distance, it produces a bizarre, "steath-bomber" shaped pattern; composed of a "dog bone" lighted section and a dark diamond outlined in light. Because it's focussed so tightly, this unusual beam shape is retained for at least 30 feet (that's as far as I can test!) and probably for a lot longer if one were outdoors at night with a white target to shoot at. I'd estimate the beam to be between 3 and 6 degrees wide; extremely narrow for any LED no matter what the color.
The beam shape is worth trying to photograph with my webcam - look for my handiwork here shortly if I can get it to work.
And here it is on the "official" calibrated test target.
The camera definitely botched the color rendering; it should appear more greenish.
The color of this lamp is the same unique, radiant turquoise as found in my Photon Micro Light II except that its beam is just so narrow. I guess I just can't get over the narrow, almost laser-like beam this LED shoots out.
If this was one of Nichia's newest models, and not something that's a year or two old already; this would easily qualify as the brightest LED on the market today, from the standpoint of flux candelas or how bright it looks when fired into your poor eyeballs.
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