I just received a prototype from Luminus Technologies, the SBT-90-R LED emitter. This red powerhouse has a die size of 3mmX3mm, and is covered by a very thin layer of flat glass, no dome. Comparatively, the Cree XPE/XPE2 red emitters have a die size of 1mmx1mm. The SBT-90 is essentially a dome-less sst-90. The data sheet spec’s this monster at 9 Amps continuous duty and 13.5 Amps max. The SBT-90 has a luminous flux of 860 LM@13.5 AMPS. I don’t know if Luminus will release this as a standard product.
The first light I built with this emitter is a T13, with a resistor mod to 3.8A on Panasonic ncr18650B 3400 batteries, and a 66mm CRELANT head with 66mm DX aspheric lens. The output is 34 Kcd, which is good for a hunting light with a RED LED (my T20’s 24Kcd) but no where near it’s full potential. More on that later.
Another T13 build here small sun ZY-t13:driver swap, RED XP-E P3, reflector and aspheric test results.BEAMSHOTS ADDED. The light in this build has been upgraded to run at 1.68A and the SinkPad was screwed down with a thin layer of AS5 yeilding 88.8Kcd behind the 66mm aspheric.
My goal with the SBT-90 was to increase the beam angle with the 66mm lens. The beam angle with the XPE2 is so small that the the projected image does not fill the entire field of view in most scopes, creating a “black” ring around the projected die image. Thus making it very difficult to use as a hunting light. If you lose the target in the “black” ring, it is very difficult to reacquire the target. The beam angle increased from 1.63 deg with XPE/XPE2 to 3.63 deg with the SBT-90.
Of course with anything there are trade offs. The SBT-90 needs at least 9 amps to reach 100% of it’s output. As the power goes up, the run time goes down. There are very few 18650 batteries that can deliver 9+ Amps. And even fewer drivers exist that put out 9A. Direct driving the RED emitters is not an option given the Vf is a very low 2.7 volts. At 9A+ the amount of heat generated is enormous, so good thermal performance is critical and difficult and expensive to achieve. If and when this emitter is released it will be expensive $$$.
I am happy with the preliminary results. I don’t know if the trade off’s are really worth it but it is a fun project. Now we will need convince Luminus or Osram to create an IR emitter with a larger die size!
At 3.8A and a dual battery set-up, this is very much a practical hunting light. Two Panny 3400’s should provide approx 2 hr run time. Generally speaking , I do not like to build big Amp “dragsters” with lots of heat and very short run times. However, I will attempt to push the limits of this emitter. More parts have been ordered. stay tuned.
The above photo shows the difference in projected image size. The xpe2 T13 on the left, the SBT-90 on the right. The distance is 20.5 ft. Image size in the photo is 7” for the xpe and 13.5” for sbt-90. The lights were set on low brightness and the camera exposure was turned all the way down and no flash used for these photo’s. They are simply too bright to use normal camera settings and overexpose when set to max brightness levels.