And this gem is that failed attempt at creating a pink LED I mentioned earlier. This sample was obtained in (I believe) late 2000.
Although this is supposed to be a pink LED, the dominant color of this specimen is a
sort of irregular brownish magenta with a blue thing in the middle, so I didn't know where else to put it.
Constructed similarly to a white LED, this piece consists of a blue LED chip plus a downconverting phosphor covering the LED's chip & anvil.
I sincerely hope this sample is simply defective, because I was not particularly impressed with either its total light output or its color consistency.
As shown by this picture, the LED isn't very bright at all. Just to obtain any image at all, I had to open the camera's iris by two full stops!
Estimated peak brightness at 30mA drive current is less than 150mcd. The spec sheet that came with it claims it has a 1500mcd output at 20mA.
That's one reason I think this LED is defective in some manner.
Here is the other.
See the reddish orange "splotch" in the center of the LED in the closeup picture on the left? For some reason, I sincerely believe it is not supposed to be there,
and that a defect in manufacturing has occurred here.
When the LED is energized, this orange area glows weakly, as does the rest of the emitting surface; and imparts the odd reddish corona
to the LED's projected beam as seen in the last picture.
When the LED is viewed off-axis at a very specific angle, it does have a warm reddish pink appearance to it. At other angles or directly head-on, it looks like
a dead or dying blue LED with a dark brownish red splotch in it.
Even at 30mA of drive current, you can easily (and comfortably) stare directly into it.
The last picture (of its radiation field) was taken by holding the LED a couple of inches away from a white sheet, driving the LED at 23mA, and photographing the whole mess from less than eight inches away.
I have forwarded this data to International Systems Processing for further analysis and some kind of answer.
Care and Feeding: The spec sheet says to feed this LED 3.6 to 4.2 volts at 20 milliamps.
When I first connected it several hours ago, I had to set it for 4.9 to 5.0 volts to get 20mA to flow through. Now this figure is 8 volts, and it continues to increase slowly but steadily!
At 4.2 volts (rated max), the forward current is only 0.5 milliamp.
While writing to the manufacturer, the LED started to randomly flicker like an amphetamine-laced Christmas tree; dimming with each flicker until it finally went out completely.
Defective? You bet.
Mr. Chang, please send another. Judging by its optical and electrical characteristics, this one is BAD.
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
True RGB Full Color LED
Spider (Pirrahna) 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 PAGE
LEDSaurus (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.