Received & tested 11-05-07
This is a 5mm round LED in a water-clear epoxy case. Unlike most other white LEDs, this one does not use a phosphor, but emits white light directly. Operating chemistry is very likely ZnSe (zinc selenide) - there is one peak at ~460nm and another, stronger peak at ~560nm. This is perfectly normal for a nonphosphor white LED, and was fully expected.
The beam consists of a small hotspot surrounded by a larger, mainly circular corona. Unlike the other ZnSe white LED I evaluated in early-2004, this one does not have that "very strong dog urine yellow" (dark amber to orangish or brownish) perimeter in its beam; the beam of this LED mostly lacks that particular "feature"; only a very narrow ring at the perimeter has that yellowsh tint to it - and it is rather faint.
Measures 8,870mcd at a drive current of 19.28mA.
That greenish-blue color is from the camera; in reality, this LED has a remarkably white color with no visible blue tint.
For comparative purposes, here is a beam photograph from the early-2004 ZnSe white LED:
Spectrographic analysis of this nonphosphor white LED at 19.28mA (***NOT*** the 2004 version!).
Note the two peaks spaced relatively close to one another.
These are LED emissions; there is no phosphor whatsoever in this lamp.
Spectrographic analysis of this nonphosphor white LED at ~1.8mA (***NOT*** the 2004 version!).
The LED appeared more yellowish than it did at ~20mA, so I ran a second spectrographic analysis of it.
Roithner Lasertechnik, zinc selenide (ZnSe) white LEDs, RLx Series
Received and tested on 03-13-04; performed spectroscopy 09-02-09
This is the world's first known zinc selenide (ZnSe) non-phosphor white LED that has been offered for sale anywhere. Although there was some work on ZnSe blue and non-phosphor white LEDs being done in the early- and mid-1990s, it wouldn't be until early 2004 that they would be made in quantities large enough to offer for sale. Roithner Lasertechnik has these LEDs in at least five types (5mm and 3mm epoxy through-hole, and three types of SMD) at the present time. The part numbers and such of the ZnSe white LEDs Roithner has are as follows:
RLZB-52, 3.5 - 4.5 cd @ 20 mA, Vf = 2.65 V, 20°, 5 mm clear epoxy
RLZB-32, 3.5 - 4.5 cd @ 20 mA, Vf = 2.65 V, 20°, 3 mm clear epoxy
RLZS-1608, 200 - 300 mcd @ 20 mA, Vf = 2.65 V, 150°, 1608 SMD package
RLZS-2012, 200 - 300 mcd @ 20 mA, Vf = 2.65 V, 150°, 1608 SMD package
RLZS-3528, 400 - 500 mcd @ 20 mA, Vf = 2.65 V, 120°, 3528 SMD package
Here's a beam photograph of one of the 5mm ZnSe white LEDs.
Measures 5,800mcd on a Meterman LM631 light meter, with an If of 30mA.
Spectrally, this LED has a strong, narrow blue spike (est. peak around 480-485nm) and a strong, very broad emission in the yellow, orange, and red; with a weaker, but still significant emission in the green. The spectrum appears to be deficient in blue-green, and all wavelengths below around 470nm (deep blue and violet). My spectrometer is busted, otherwise I'd show you with a spectral analysis.
This LED produces a beam with a slightly but noticeably bluish-greenish-white central area, with a "very strong dog urine yellow" (dark amber to orangish or brownish) ring outside that. This is expected behaviour with a non-phosphor, 3mm or 5mm epoxy lens LED, and does not in any way indicate a problem with this type of lamp.
From the datasheet, comes this snippet:
o The half-life of the optical output at 25°C is over 3,000hrs at the above If condition (20mA).
o Recommended If at 75°C is 5mA. The half-life under such condition is over 1,000hrs.
o The half-life of the lamp is inversely proportional to the square of the operating current.
They still have a small problem with short device halflives, but it's still pretty decent for a lamp.
(Update 04-01-06
Spectrographic analysis of a Roithner Lasertechnik # RLZB-52 (5mm) ZnSe (zinc selenide) nonphosphor white LED.
(Update 09-02-09
Same as above; different spectrometer & software used.
Spectrographic analysis of a Roithner Lasertechnik # RLZB-32 3mm ZnSe (zinc selenide) nonphosphor white LED.
USB2000 spectrometer graciously donated by P.L.
WHITE 5500-6500K InGaN+phosphor ULTRAVIOLET 370-390nm GaN BLUE 430nm GaN+SiC BLUE 450 and 473nm InGaN BLUE Silicon Carbide TURQUOISE 495-505nm InGaN GREEN 525nm InGaN YELLOW-GREEN 555-575mn GaAsP & related YELLOW 585-595nm AMBER 595-605nm ORANGE 605-620nm ORANGISH-RED 620-635nm RED 640-700nm INFRARED 700-1300nm True RGB Full Color LED Spider (Pirrahna) LEDs SMD LEDs True violet (400-418nm) LEDs Agilent Barracuda & Prometheus LEDs Oddball & Miscellaneous LEDs Programmable RGB LED modules / fixtures Where to buy these LEDs Links to other LED-related websites The World's First Virtual LED Museum The Punishment Zone - Where Flashlights Go to Die Legal horse puckey, etc. RETURN TO OPENING/MAIN PAGELEDSaurus (on-site LED Mini Mart)
This page is a frame from a website.
If you arrived on this page through an outside link,you can get the "full meal deal" by clicking here.