High-flux white LED (4-chip), www.zexstar.com, part # LFLHW4
(Rec'd 06-26-06, tested 06-28-06)
This is a high-flux ("spider") white LED, which has an apparent color temperature of 6,500°K, which is a somewhat cool white in color. It has four dice (light-emittimg chips) in parallel with one another.
At a test current of 70mA, intensity was measured at 5,740mcd.
Published intensity value (at 80mA) is 4,100mcd.
Vf was measured at 2.996 volts.
I'm not equipped to measure beam angles at all. It is published as 100-120°.
Spectrometer plot of this high-flux white LED. Ocean Optics USB2000 Spectrometer on loan from TWO-CUBED.
Taillight "rounds" and center high mounted stoplight LED (CHMSL), manufactured by Lumileds
You've probably seen a lot of these lately. But this is a look you may not have seen before: Lumileds taillight and stop light modules, fully "undressed"! (Does this mean I need to put
one of those "rated TV-14" thingies on my front page because of full frontal nudity of an LED?)
One of the rounds mounted to my wheelchair and functioning as a tail light.
Holy cow, look how BRIGHT that sucker is!!!
That's a daylight picture with no flash and the whole back of the room is bathed in the intense red glow. Also note the two square red taillights aren't even on. All the red is coming from the Lumileds product!
STAY TUNED FOR MORE INFORMATION ON THESE PARTS!
STAY TUNED FOR MORE INFORMATION ON THESE PARTS!
"Spider" (4-lead) high-flux LEDs
"Spider" (4-lead) high-flux LEDs
Below is an example of a "spider" LED, so named because it has all those legs and bears some passing resemblance to our arachnoid friends.
The trade name for these high-flux LEDs is the Pirahna, and most of them (at least the ones that go under the market name of Pirahna) are manufactured by Lumileds.
Housed in a squat, usually square shaped package, these LEDs see widespread use in signs, message boards and automotive lighting.The main reason for the large metal area inside the LED is to help vent away excess heat, since these LEDs are designed
to be operated at much higher currents than ordinary LEDs, often as high as 70mA continuous.
Viewing angle on these LEDs is usually very wide, and sits at around 150 degrees or even more,
depending on the lens shape. In the picture below, you can actually see the light emitting chip under the tiny domed lens in the center.
Brightness is fairly high, but since the viewing angle is so wide, they won't appear as bright as most T1 3/4 style LEDs using similar dice - at least until you jack up the current towards their 70mA rating.
That's when they really shine.
Close-up of a spider LED.
Several of these interesting LEDs showed up in a parts bag; a couple in bright red and a couple in bright yellow.
Two of the multiple-LED clusters from the assortment of them I got several months ago use brilliant orange "spider" LEDs.
Telefunken "spider" LEDs, model TLWx7600 (4-lead) high-flux LED
Some people say watch what you wish for, because you just might get it.
Such is the case here, when these Telefunken LEDs showed up. They came in orange, yellow true green, blue, and white.
These LEDs all arrived together, and are of the same model type and style. As marked on the bags:
TLWR 7600 (Reddish-orange)
TLWY 7600 (Yellow)
TLWG 7600 (True green)
TLWB 7600 (Blue)
TLWW 7600 (White)
The orange and yellow ones can take 70 milliamps continuous; the rest are limited to 50 milliamps.
(The photograph shows a blue one on the left, and a white one on the right).
The orange and yellow models appear to light up at least as well as a low or middle ranking Pirahna LEDs (made by Agilent); while the others were a little dimmer than expected.
The light emitting chips in the green, blue, and white appear to be gallium nitride on a silicon carbide substrate; as they have what is called "single bond construction" in which a single thin wire attaches
to the center of the LED chip. Cree Co. (formerly Cree Research) pioneered the gallium nitride LED using single bond wire construction. Most blue, green and white LEDs used today
though are the Nichia type, which feature a much larger chip with two wires attaching to opposite corners of the chip.
These LEDs are usually at least several times brighter than the older chip style using a single wirebond.
From what I can determine, this newer, brighter technology wasn't used because LEDs made from this material cannot withstand the higher than usual operating temperature for
very long before they begin to degrade and become dim. The older type (the Cree type) apparently can withstand this, so that's why Telefunken used this chip type in their spider LED.
