LEDTRONICS L200-CWGB6-100 BLUE- GREEN LED FROM THE EARLY-1990S
L200-CWGB6-100 Blue-Green LED from LEDTronics
Sent by Jordon P. of LEDTronics, and was received 05-06-03
This is arguably the first Indium Gallium Nitride LED to show up outside a laboratory setting. It is a LEDTronics model L200-CWGB6-100. Look closely...
what do you see? More precisely, what don't you see?
That's right! No bonding wires at all. The very large crystal of either silicon carbide or artificial sapphire doped with a gallium nitride emitting layer was simply
flipped upside down and clamped onto the surface of the LED's metal leadframe!!
The faint, silicon carbide-like glow came from a small region on the cathode where contact was made between the metal leadframe component
and the GaN slab. This LED's peak wavlength was approximately 485nm, which is a turquoise shade of blue; not that unlike most of the earlier silicon carbide LEDs.
It was originally intended to be used in a colorimeter. Soldering to this LED would have been extremely difficult and result in a high mortality rate, as every single microdyne of stress placed on the LED's leads was transmitted directly to the poor chip inside. Heat from soldering would soften the plastic of the LED case, only compounding the problem.
The only way this LED could have survived installation in a commercial application is by socketing, and even then, a strong enough hit to the cabinet of a machine equipped with one of these (or a fall from the lab bench to the floor) just might be enough to kill the poor, innocent, helpless, defenseless LED.
According to my source, this LED was made in 1993 or 1994 and sold for only a short time before brighter and more robust GaN LEDs began to come out of Shuji Nakumura's lab at Nichia.
Check out that pebbly texture in the region emitting the light in this magnified top view. This is probably indicative of a clamp of some kind that applied tremendous pressure
to the GaN chip in order to make a bond with the metal leadframe structure it is mounted to.
The spectrum of this LED was unusually broad. At lower currents, this and even most modern GaN and InGaN type LEDs tend to have very broad spectrums with a lot of green & red and not much blue.
At its nominal operating current of 10mA, the color would have shifted noticeably toward the blue and the emission in the red would not increase nearly as much in relation
to the rest of the LED's output.
More importantly, this picture shows how large the LED die is in relation to the rest of the the structure, and the small size of the actual emitting region compared to the size of the
die as a whole. Even by today's standards, this would be considered a large junction device, even though only a small portion of it is emitting any energy.
The other remarkable feature is that this LED had a Vf of 11.0 volts(!!!) at If=10 milliamps
Photographs of this LED courtesy of Paul Schick.
As of 05-06-03, I now HAVE one of these wily and elusive LEDs, and I didn't have to bash open an old colorimeter to get it!!!
Stay tuned to this station for additional pictures!!!
Spectrographic analysis of this LED at an If=10mA.
Spectrographic analysis of this LED again; spectrometer's response narrowed to a band between 420nm to 650nm.
Spectrographic analysis of this LED again; If= 230ľA (0.230mA).
Spectrographic analysis of this LED again; If= 230ľA (0.230mA), spectrometer's response narrowed to a range of 420nm to 650nm.
Spectrographic analysis of this LED again; If= 15.555mA.
Newest (01-13-13) spectrometer software settings used.
Spectrographic analysis of this LED again; If= 15.555mA.
Spectrometer's response narrowed to a range between 475nm and 495nm to pinpoint peak wavelength, which is 487.320nm.
Newest (01-13-13) spectrometer software settings used.
Spectrographic analysis of this LED again; If= 190ľA (0.190mA).
Newest (01-13-13) spectrometer software settings used.
Spectrographic analysis of this LED again; If= 190ľA (0.190mA).
Spectrometer's response narrowed to a range between 480nm and 500nm to pinpoint peak wavelength, which is 492.200nm.
Newest (01-13-13) spectrometer software settings used.
Do you manufacture or sell an LED flashlight, task light, utility light, or module of some kind?
Want to see it tested by a real person, under real working conditions? Do you then want to see how your light did? If you have a sample available for this type of
real-world, real-time testing, please contact me at ledmuseum@gmail.com.
Unsolicited flashlights, LEDs, and other products appearing in the mail are welcome, and it will automatically be assumed that you sent it in order to have it tested and evaluated for this site.
Be sure to include contact info or your company website's URL so visitors here will know where to purchase your product.
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.
