3rd generation Oslon Square, a 5000K 70CRI led tested

The third generation Osram Oslon Square has been for sale for a few months already, but (with my admittedly narrow view on the world) I have not seen it tested or used yet. It is not a Cree led so, apart from some interest on TLF which is how it was brought to my attention (chouster mentioned it to me), I have not seen it mentioned much... let's see if that is justified.

From rs-online I bought the minimum of 5 of them (for about $2.20 each so about XP-G2 price) , in 5000K 70CRI. Partnr. GW CSSRM2.PM-NPNR-A333-1 . RS-online has it in 3000K, 4000K and 6000K too, but I have not seen higher than 70 CRI variants for sale yet.

The appearance differs from the former generation Square in that the dome is significantly larger, and completely spheric instead of flattened on top. The size and shape of the dome is very close to the XP-G2 now (but the smaller 3030 package of the Oslons make it look a bit out of proportion). As with all the latest Oslons, the phosfor is a 'poor' over the die and its surroundings. Here's the 3rdgen. Oslon Square physically compared to an XP-G2, left the Square (under 0.5mA current to light up the die area), right the XP-G2 (not lighted):

The die size is as good as the same too.

The test was done like all my more recent emitter tests. I described it in detail in my XP-L test. , with two minor differences that should not matter significantly for the results: I used my Integrating sphere no. II instead of no. I, and for the current I used a clamp meter, which appears to measure 0.1A lower than the power supply current-reading that I used before.

In summary: 1) just one led was tested, reflowed on a DTP copper board (XP-Noctigon 16mm) 2) I used my large version II integrating sphere with high quality luxmeter, 3) the output numbers and voltages were measured with the led close to 'steady state' for each current, so warmed up and settled, you should be able to get these numbers in a well heatsinked flashlight. Mind that these are output numbers of the bare led, in a flashlight there will be losses from light obstructions, lens and optic, 4) output is in 'djozz-lumen' defined as 1/550 of the output of my Sunwayman D40A on high setting, which I hope is close to the real lumen, but at least is consistent over all my emitter tests done in integrating spheres.

Here's the results, compared to several other leds that I have tested using the exact same method:

What can be said about the 3rd-gen. Oslon Square from this graph?:

*compared to the 2nd generation Oslon Square, the 3rd generation is thermally improved and has a bit lower voltage (0.15V lower at 5A). (the outputs of the 2nd and 3rd generation in this graph can not be compared because the tint and CRI are way different)

*compared to the led that comes closest in specs from what I tested, the XP-G2 S4 2B, it performs clearly better: above 3A the output is higher, the voltage is no less than 0.6V lower. This makes this led the best performing led in this die size class that I have tested sofar. A 70CRI Nichia 219C (not tested by me) may come very close though...

*the XP-L Hi has better output (tested is a U6 bin, and there's a V2 bin out there too so the output is even more then), but its voltage is a bit higher (0.2V at 5A).

*it maxes out at 7A, which is better than any of the leds with this die size, only the XP-L (Hi) has its maximum at a higher current (7.5A) but has a bigger die. (btw, the output dip of the XP-L Hi at 5,5A was caused by part of the die getting damaged during testing)

*the bond wires of the Square incinerated at 8.6A, which is comparable to what happens to the XP-G2, at least the old ones (the Nichia has no bond wires that can blow)

*the low voltage of the Square is only matched by the Nichia 219C, the latter being even lower at really high currents.

With this performance, beating the XP-G2 S4 2B, this is a very interesting led. But, as discussed in another thread on BLF, it is debatable what the advantage is of a XP-G size led with dome, now that there's the XP-L Hi that shows very similar optical properties with higher light output. On a single Li-ion cell, the Square may still show a similar light output as the XP-L Hi because of its lower voltage, but consequently at higher current.

This Square becomes increasingly interesting if it can be dedomed. I have never manged to succesfully dedome any Oslon, but had a go at a hot dedome anyway with the burnt test-led (hence the blackened bond wires in the pictures below). And of course failed:

The dome comes off alright, but the phosfor appeared to be a sort of sludge, not solid at all like the Cree phosfor layers. Another approach could be slicing the dome, but because of the bond wires sticking out, a significant layer of silicone will have to be left over the die, this will not help the photon recycling needed to increase the luminance of the die.

edit: my first attempt at a test with shaved dome is in post #9

Conclusions

This 3rd generation Osram Oslon Square is a great performer, so much that Osram has 'overtaken' Cree in the XP-G class. It seems to perform even a bit better than the Nichia 219C. But the big drawback for high end flashlight use is that it can (sofar) not be dedomed to increase the luminance of the die, like the XP-G2. And with dome on, the Square has a strong competitor in the XP-L Hi, close to same optical properties with a bit higher output. It is much cheaper than the XP-L Hi though, so that may make it attractive to use instead (for swapping the leds in your 12-led SRK clone ;-) )

I have not evaluated the tint of this led, for that I need to build it into a flashlight and gain an impression. I may do that in the near future :-)

Thanks for reading!

Great info as usual, especially for going out on a limb with an led most aren’t familiar with.

One question about the sludge of phosphor, a lot of people are just shaving the dome now instead of completely removing it. Do you think that might bridge the gap between using one of these vs an xpl-hi and a fully dedomed xpg2?

I wrote something about that in the OP, I called it slicing the dome. It is something to try out indeed, but you can not get as close to the die as you can with the Nichia leds because there’s bond wires sticking out.

Wow, impressive.

That little comment has me very interested in the 70cri 219c too

I have no idea what gen. my 4500K 83CRI square is.

The competition from another manufacturer can only be good for us all here. Again orsm testing djozz. Thanks.

Thanks Djozz.

Just placed an order for a few of the 6500k’s from RS.AU.

Will hopefully get them before the weekend, so I can have a go at de-doming using a few different methods.

Thanks for the comments, guys!

That would be great! I’m looking forward to how this led will perform in actual flashlights.

First attempt at a comparison of the 3rdgen Square in an actual flashlight. I shaved the dome right up to the bond wires, not a great clean shave if you look at light reflection from the surface of the cut, but the die is sharply visible through the silicon and that is what reflectors and lenses see as well. I made a direct drive pill for my Brynite 358 with it (so sliced 3rdgenSquare on 16mm Noctigon, FET-converted AK-47A) because I have a direct drive pill with a dedomed XP-G2 S4 2B as well for direct comparison, the latter does 322kcd. (I did not solder the board to the pill this time but used the plastic screw-in retainer that Brinyte provided, with a thin layer of ArcticSilver5 in between board and pill)

The hotspot is not pretty:

There’s a bit of dirt in the corner.
The current (measured without tail) by the XP-G2 S4 2B pill in this light, with a Samsung 30Q, is 4.2A, the Oslon Square pill draws 6.85A which is right at its maximum output in the bench-test. I measured throw in the Brinyte, measured at 7 meters, I get 208kcd. This is as low as I feared, and since I do not see a tint shift (colour temperature looks like it is still 5000K) I think the cause is a minimum of phton recycling with this thick layer of silicon still over the die (too much light can escape to the side, and the surface diffuses more than reflecting light back into the die).

I hope that FmC gets the dedoming better done than I did.

Hmm - I hope it fares better in a reflector!

Thanks for taking the trouble to do a nice test and try a dedome.
It looks like it might beat everything for small cell lights, and for lights that need boost drivers that tend to be more efficient when the LED voltage is closer to the battery voltage.

Does anyone know a source that might be better for US buyers? If not, how did you get around the assumption that one is in Britain?

I don’t know a US source that is up to date in Osram leds (Digikey lists many but most of them are not stocked), I happen to live in a country with an accessable Osram-distributor and I’m lucky for that. But RS-online is not even accesable for everyone here because you have to be a company to order there. At my work (a secondary school) I’m allowed to do a private order every now and then.

Availability is an issue if you want something different from the majority. Nichia’s are impossible to obtain apart from the few types that are sold by sellers of flashlight parts. LG makes some very promising leds but I have no idea where to get hold of some for testing. Even for Cree leds I have to wait for what types are stocked by Mouser, Intl-outdoor or MtnElectronics.

Wow, I didn’t realize Osram was still around, much less making competitive LEDs.

The last one I saw was the Osram Golden Dragon, which I have in a 3xAA TIR puck light from at least a decade ago. It was pretty impressive at the time, wanted one in a flashlight, but that was before I knew about Cree.

FWIW- I have really rotten hearing but I met a fellow about 6 months ago who worked for a company that manufactured industrial lighting using Osram emitters, and from what I could get from the short conversation he felt they were great emitters for their needs giving high efficiency and very long life. He quoted specs of several of them but that was (and still is) way beyond my limited knowledge and of course none of that stuck with me. Based on that I’d say Osram is still alive and kicking, though maybe more focused on less portable lighting needs. Perhaps that is changing now? One can only hope!

Phil

Osram is one of the main early 20th century electric light brands, probably the one who financed Max Plank’s black body measurements that led to quantum mechanics and its applications including LEDs.

On the Osram site, apart from 70CRI, now the 80 and 92CRI versions of the gen.3 Oslon Square are also listed. I have not seen them for sale on rs-online yet though.

These should be competition for the high CRI Cree XP-G3, and for the upcoming high CRI Nichia 219C. I hope for a better beam in reflector lights than the XP-G3.

In yet another irony?

I follow OSRAM very, very closely on another forum? BUT only as regards to their infrared emitters, lol… heck i always figured if their visible emitters were as good or better than CREE emitters? They would already be featured on HERE all the time

No, Osram is not ahead of the rest, yet.

Their visible emitters were behind in output earlier but lately they (almost) match the output of comparable (XP-G2/3) Cree leds. But Cree has emitters with bigger dies that outperform the Osram (Square) leds. Then again Osram makes the SSL80 leds that have a narrow emission that I like for small zoomies

The tints are a matter of taste, there’s not many Cree tints that I like, even not the 80CRI ones, the Osram tints I find better, but then again Nichia tints are nicer even.

The 3rd generation 90 CRI Osram Oslan Square’s have recently been added to Mouser and Digikey sites for just above $2 each. Available in all CCT 2700K, 3000K, 3500K, 4000K, 5000K, 5700K, and 6500K! Pick any one you want!!!

Yes, I forgot to post that I bought some of the 90+CRI 3000K ones and put some in a Jaxman E2L triple. The tint is better than the gen.2 version of same tint/CRI. I think I posted something in the what did you mod today thread (link follows)