Cheap bare 385nm UV LED

You know what I just thought of? If these are not the exact same emitters, then how do we know if they are even the same wavelength as the ones we asked for? Is the original LG packaging present and labeled appropriately?

No, it is a matter of trust. I did check their earlier LG leds and they were dead-on 385nm. I could check these too but will not bother actually, it is not that the 385nm ones are more special or expensive than the 395 or 405 ones, I think that they know their leds but just don’t understand their customers.

That’s good enough for me. As many LEDs as you’ve tested over the years, if you can trust them, so can I. I don’t have any particular attachment to any particular wavelength anyway. I’m just buying these to play with. :smiley:

on the pic the dome looks taller than normal? is it the case, or just optical illusion?

So i got answere from the seller.

Like we could expect it is the lowest flux bin. But also the lowest Voltage bin with 3,2-3,4V. This should help to get a little bit more out of the leds.
At the moment there is only one person that has not payed and did not answere the PM. But i want to wait till tomorror. If i did not hear from him till then djozz and NeoGeo can have the leds. I do not know how much djozz or NeoGeo needs but that problem can be solved.

I’d be interested in 1-3.

So, how does this lowest bin of the newer gen compare with the LEDs we were originally expecting? Since you have the info now for these LEDs, I’m just curious what the output difference is. :innocent:

All leds are paid for. Sorry for all that are to late.
We do not know how much output they produce above 700mA (out of specs) but in spec there is not much difference in output to the old one he tested. Now we have to wait for djozz test to see how they perform above factory settings.

It is a pity that these are the lowest bin possible, I hoped for a more average bin. It should still be ~100 mW above the older generation led.

I do not know how well they perform above the specs. the thermal resistance is better than the older led, but I found in 365nm leds that the output of the die has a sharp output limit regardless of temperature, so temperature may not be the bottleneck. On the other hand, 385nm leds have a different type of die than 365nm leds so may have other characteristics as well.

In other words: only a test can tell, and I hope to check the led this weekend.

TheOnlyDocc has given me the addresses to where the leds will be sent , and try to put them in the mail as soon as I have time.

Thanks djozz!

I asked the seller if he could get these LEDs in a higher flux bin (like HP15). If he is able to source the LEDs for a good price i maybe will do a second order round. But only if he really can get one of the higher bins.

Look forward to hearing what they say.

The seller has to many LEDs in stock at the moment. But next time he has to restock he will try to get some with higher flux bin. If he can get them he will let me know.

Thanks for checking. Please keep us updated here.

I have sent 37 leds in the mail on friday.

And yesterday evening I did an output test on the led (will call it the 4th gen. LG 3535 UV led). Do not expect anything as accurate as my white light tests, my method of testing UV leds has many imperfections leading to probably large errors (method here). Errors are caused by fluorescent bleaching of the used copier paper, variation of fluorescent die in the paper, but also higher than average output drop upon warming up of UV leds. On top of that the new led has a vastly different emission angle which also will cause extra error the way the led illuminates the paper. The measured voltages however are as correct as my normal led tests.

So I was quite surprised how close this led tested to the 3rd gen. version I tested 2 years ago.

The main difference is the much lower voltage of the 4th gen. led which makes even this lowest bin more efficient than the 3rd gen. that was tested, so it can not be direct driven on a single li-ion anymore but must be regulated (i.e. by a 7135 based lineair driver). And like the 3rd gen. led the sweetspot for me is 1.5A.

I expected a low Vf at the V1 Voltage bin but this is really low. Mhh the idea to use a FET on the MELD-X Driver for the UV channel is no longer a good option. And i do not think that all the parts will fit on one PCB. Not if i want to go up to 4-4,5A on the UV channel (tripple UV) and 700mA on every other channel. This would require 20*7135 chips.

Did anybody know a source for the good “Raptor claw” 7135chips? I have a few left but they will not last long. And with more low Vf LEDs getting on the market i want to stock up a few if i can get them.

Hi Docc, if you are in contact with the seller next time, could you ask him if he would stock LEUVA33W70RL00 ? That is a led I have been eying for more than a year and is nowhere to be found: 365nm, 1000mA, 1800mW radiant power. Small chance that he will bite, but who knows? :slight_smile:

No direct drive? Thats a bummer, now i have to order extra drivers for this :cry:

Oh well no big deal. Saved enough on the dies that i can maybe get a couple nanjg’s sent over.

No problem djozz. Mail is send. And maybe we get the leds we want for a good price.
Another question is how to drive a UV tripple with this leds? And at the same time the mc-e with the same driver. Is there a better way than using 20* 7135chips?

Ps.

- Did anybody know a source for the good “Raptor claw” 7135chips? I have a few left but they will not last long. And with more low Vf LEDs getting on the market i want to stock up a few if i can get them.

  • Is there a cheap source for a 385nm filter lens? Like the ZWB2 for 365nm.

@djozz
I found this PDF and there are a few leds that i find interesting (https://www.lasercomponents.com/fileadmin/user_upload/home/Datasheets/lg/lg_uv_led_overview.pdf).
1.LEUVA33W70TL00
https://www.irtronix.com/leuva33w70tl00

But what kind of ledboard would i need for this leds?

2. LEUVK33W80TV00
https://www.irtronix.com/leuvk33w80tv00

3.LEUVA66X00TV00
http://www.irtronix.com/leuva66x00tv00