UV LEDs (...again) advice

[absolom7691]

So, I have never liked UV LEDs as a blacklight replacement for discharge lamps due to the prevalence of 390nm~405nm LEDs (which are not blacklight wavelength). I have noticed a huge price drop in *true* blacklight LEDs. I see a bunch of different sellers on ebay that are selling 365nm~370nm UV LEDs. This is right in the sweet spot of what I am looking for. Does anyone know if these sellers are being *honest* about the wavelength? I know it is difficult to trust Chinese LED sellers in regards to honest lumen ratings but what about wavelengths? http://www.ebay.com/itm/5X-3W-365nm-...item233d179885 <-- these are touted as 365nm... Has anyone had experience with any such sellers/products like these? I would hate to pay a premium for LEDs that are actually 390nm~405nm instead of the advertised 365nm~370nm as this would be a waste of money and also time. That said, are there any LED vendors that you guys trust more than others?


macona, I am hoping to see you chime in!

[krazer]

The abysmal efficiency of under 2% (according to their spec 55mw for 2.5w input), compared to >20% for a half decent 400nm device, would imply that they might be real. Either that or they are just really dim so they look like they are further in the UV

[absolom7691]

Thanks. I hadn't spent much time reading the specs.... wow. The output is ridiculous!

http://www.mouser.com/new/ledengin/l...65nm-emitters/ <-- These look promising. I trust Mouser and Engin. These are also 10x the price per unit but, the chip looks way better built and the output is 20x that of the cheapy ebay LEDs. I think I may just try a couple of these guys.

[swamidog]

try sending a ping to csshih. he runs a high end led flashlight shop and may have a line on some good uv leds.

[dkumpula]

I've been watching out for a true-UV LED DMX fixture for years and haven't found much. When I thought I did, the vendor wouldn't even reply with pricing and availability. If these LEDs pan out, I'd be really interested.

-David

[norty303]

Yep, LED UV with minimal visible spectrum and high power is the holy grail

[absolom7691]

I've been watching out for a true-UV LED DMX fixture for years and haven't found much. When I thought I did, the vendor wouldn't even reply with pricing and availability. If these LEDs pan out, I'd be really interested.

Absolutely. I think I may try some of these Engin LEDs. Newark has them for $17/ea: http://www.newark.com/ledengin/lz1-3...85550001536104

1000mW max luminous flux, 800mW avg. 2.8W.... These look pretty nice. Here's the spec sheet. http://www.farnell.com/datasheets/1801210.pdf


EDIT: NM, 100pc min order.

[Draco]

I have an array of the cree brand 3 watt leds on a star base mounted to a heat sink, they defently make your eyes feel like you are looking at a long wave black light but there is still light outside of the range, kinda like the epoxy is florescent and would benefit from filter glass for that true non fluorescent black light effect. my idea is to use them to stimulate some minerals that repond to long wave uv and as long as the epoxy blob is not in direct view they tend to do an ok job. i will post a pic once i can figure out where i relocated the array. I use some long and medium wave rocks as laser targets for my 405 and 450 pointers as well when i get bored

I would like to try it with a filter something like that http://www.uvsystems.com/store/produ...6&cat=5&page=1

I have dealt with this company before. they are expensive but you get what you pay for, when i built my shortwave light source I bought the filter glass from them and i know it's almost to the end of the filters life it still has nice output, as you know short wave is very destructive to the filters

[Draco]

that's the array




both are with a shutter of 2 seconds with and f stop of 3.5 on a Sony DSC-F828 and i screwed up and left the uv filter on but they proximate what it looks like to my eyes, the array is on the arm of my chair at a distance of 2 feet. the rock if memory serves is Calcite from the Franklin Mine, New Jersey i think.

The leds still have a ways to go in order to compete with florescent lamps but still fun to play with and very portable

[absolom7691]

Very nice. Thank you for posting some pics.