A China company (Bell Van) is advertising a 365nm, 5w flashlight based on what appears to be the CUN6GF1A chip from Seoul Viosys. The specs say 1150mw radiant, so it must be driven at 1000ma? A 5 watt would have to be driven at the max of 1400ma, but I have a hard time believing it is driven at 1400ma - I don’t see how the flashlight could handle the heat.
Supplied with a ZWB2 filter, priced around $25 (I’ve been told 3rd hand). I have an email inquiry into them to confirm.
Anybody have experience with this company or the Seoul chip?
Don’t know about that. The s2+ with the Nichia chip driven at 700ma get pretty warm. Driving the Seoul chip at its max rating of 1400ma is on the edge. Derating at 1400ma starts at 40C with excellent heatsinking, 10C with lousy heatsinking
$25 is a great price for a 1W radiant output 365nm flashlight with ZWB2 filter. I have not had one of those Seoul leds, but it has the standard 3535 footprint, so if you don’t trust the lifetime of the led, you could change the ledboard with a DTP board and vastly improve the thermal drain of the led. Or maybe a DTP board is already in there and that is how they get away with 1400mA.
Maybe - I’ve sent an email asking for details on the driver and heatsink. Problem is I’ve never heard of this company and have no idea of the reliability
OK - just got the quote, very interesting = $25 in low qty. They use the CUN6GF1A Seoul Viosys chip, driven at 1000ma. Driving at 1400ma will overheat he says. Simple on/off driver, with ZWB2 filter. I’m going to order a couple and check them out. Sounds promising…. Will try to update here once I receive them.
1150mw vs 640mw (stated specs - radiant, not yet tested). Quite a bit more powerful. Of course reflector design will matter quite a bit. I ordered four of them to test/tear apart
FWIW, the most powerful UV 365nm emitter Nichia makes is the NVSU333A. It runs at 3800mA and makes a LOT of heat. And it sells for $108 for the emitter itself, if you can get it. I had to sign a waiver of release and submit an order on my company letterhead.
This is to say that it’s not easy, or cheap, to get a true high power UV emitter.
Yeah - 3640mw radiant. Almost need liquid nitrogen to cool ;) Luckily in our application (mineral fluorescence) we don’t need pinpoint light sources. We’re not interested in throw but in a wide intense beam (floodlight). Pretty easy to hook up 3 or 4 of the cheaper LEDs and get close to the radiant (4ea Nichia 033 chips would give ~2500mw @$4 each). I built a 4 LED light using the LED Engin LZ1 parts for >6.5W radiant.
Here’s an example of the way we use these LEDs for mineral lights:
I have it mounted in a solid copper X6. Works well, I made a chunky aluminum “reflector” that gives a square hot spot but prefer to use it in mule configuration.
Edit: My primary point though was that if a company is declaring a “high output” UV emitter at a $25 price point something is probably amiss…
I guess it depends on what you consider high output. A 9watt CFL (fluorescent) bulb outputs ~1.5w of UV (UVC or UVA). An LED which outputs radiant 1.5w UVA is considered pretty high output for us. Even the little Nichia 276 at 600 to 700mw but in a very tight beam, all radiated from a single point far exceeds the perceived power of a CFL bulb. So my focus is on replacing fluorescent bulbs where I can with these very directional LEDs. If only a reasonable UVC LED were in my future - sadly afraid not. 10mw/20mw just won’t cut it…
From a UV watts to dollar ratio I find the LZ1 part to be quite effective. But would drool to have what you describe - and mule config exactly what FL mineral collectors want. Did you also install a UV bandpass filter? With the $$$ you have invested in that light I would consider using Hoya 325c - the best filter you can get…
I had researched and located the Hoya lens but never bought it. Kinda like seeing the emitter in this copper light. (off, of course!)
Edit: From datasheets, the Hoya 360 would give a much sharper cut off for this Nichia, but where to find one in 35mm?
Edit II: I also have the LZ1 and a couple of the smaller Nichia’s, the LZ1 does perform well as does the little Jaxman offering in the U1 with it’s black bandpass filter lens.
I cut all my Hoya glass. I have squares which I trim down to hexagons with a diamond saw, and then round it off using a lapidary wheel. The advantage of being a rock collector
