Some interesting 365 nm UV LEDs online

[Stefano]

I was looking at some 365 nm UV LEDs on Mouser, a website that is available in Europe for sure, but I don't know if you can buy from it in the US or other countries. From what I understand, it is a platform (like Amazon or eBay), where you can find items from various manufacturers, like LED Engin, Luminus Devices, Texas Instruments and so on. You can find LEDs, photodiodes, ICs, power supplies and in general electronic stuff.

 

I have no affiliation with Mouser or the individual manufacturers.

 

All LEDs emit at 365 nm. I will not say it every time, since it would be repetitive.

 

If you don't know how to properly drive an LED, see this topic: https://www.ultravio...-power-to-a-led

 

I suggest you to read the datasheets of the LEDs for more information. I will only report some of it.

 

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https://eu.mouser.co...252BksMHA%3D%3D

 

Manufacturer: LED Engin

 

Datasheet: https://eu.mouser.co...020-1915176.pdf

 

This is a 10 W LED consisting of 4 chips, similar to mine, but without the lens. The chips are wired all in series (4S configuration), while my LED is in the 2S2P configuration. This way the current is the lowest and the voltage is the highest. Also, you can be sure each chip gets the same current. If you read the datasheet, there are two output power bins. The T bin has the lowest output power. I guess it is the least efficient version, and it seems this is the version they sell. But then they state the typical output power at 700 mA, which is 4.1 W.

 

Typical values (at 700 mA):

Forward current: 700 mA;

Forward voltage: 15.2 V;

Input power: 10.64 W (calculated by me from the data above);

Output power: 4.1 W;

Efficiency: 38.53% (calculated by me from the data above);

 

I wonder if an LED in the U bin can reach 50% efficiency. Note that you can drive this LED at 1 A of current (read the Absolute Maximum Ratings), but it is probably near saturation and the efficiency will start to drop. It isn't really worth it to overpower it, in my opinion.

 

They sell also the chip alone: https://eu.mouser.co...v723tzyvw%3D%3D

 

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https://eu.mouser.co...GJAh68Jv%2F0%3D

 

Manufacturer: Luminus Devices

 

Datasheet: https://eu.mouser.co...eet-1504881.pdf

 

This is a pretty powerful LED. Luminus Devices claims over 20 W/cm² of irradiance, which is more than enough to burn things (if you really like to do that). Be careful, don't operate it with something sitting on top of it, it will burn it!

This LED has 12 chips connected in a 4S3P configuration. This version is currently non-stocked. This LED is quite expensive, but seems to be a very good one.

 

Typical values (at 2.25 A):

Forward current: 2.25 A;

Forward voltage: 13.4 V;

Input power: 30.15 W (calculated by me from the data above);

Output power: 10.6 W;

Efficiency: 35.16% (calculated by me from the data above);

 

Note: you can drive this LED up to 4.5 A. It is not at all saturated at 2.25 A, you can really push this little beast at more than double than that (see datasheet, page 6).

 

LED alone: https://eu.mouser.co...mKhxM42878sY%3D

They sell them on other supports (code starting with CBM) but they are a slightly different version (H365 instead of I365).

 

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https://eu.mouser.co...51vy334UA%3D%3D

 

Manufacturer: Inolux

 

Datasheet: I can not put a working link. Click on it from the first link.

 

This LED is special since it has a really narrow beam of 30°, although the cut-offs don't seem to be very sharp. A narrow beam angle means it is easier to collimate it using a lens, without wasting light. You will not need a very thick lens with a short focal length, but a more common, flatter lens will work. Of course you don't need a narrow beam angle to collimate a light source, but without that you will waste a substantial amount of light to the sides, lowering efficiency. Don't use this LED with a parabolic reflector, as it will simply "avoid" it, like if it wasn't even there. The LED is unmounted.

 

Typical values (at 1 A):

Forward current: 1 A;

Forward voltage: 3.7 V (calculated by me as an average between the minimum and maximum voltages, as they don't specify the typical voltage);

Input power: 3.7 W (calculated by me from the data above);

Output power: 1.6 W (read from the first link, not from the datasheet);

Efficiency: 43.24% (calculated by me from the data above);

 

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For now, that's all. There are a lot more LEDs you can find there, IR ones too. Just search.

[dabateman]

Well the luminous one is minimum $7000, as you need to buy 50 at $140 each.

 

For us in the US it works, but redirects you to US listing.

 

[Stefano]

Wow, I didn't notice that. Here it would cost almost 6000 €. Too bad you can't buy them in single units.

 

Nice to know it works in the US.

[ulf]

Mouser is one of the big general distributor houses with a vast number of different components available.

When designing electronics and prototyping such sites are where you do general searches and order for projects.

There ar some other similar places.

Digikey https://www.digikey.com/

Farnell https://www.farnell.com/

are two others and they sell globally.

There are more, but these three are my main sources.

 

Those are the places I use professionally for design prototypes, but from som of them it is also possible to buy privately.

 

When producing electronic devices there are other sources closer to the component manufacturers and then the purchases are for much higher volumes based on future production volumes. The companies building the complete circuit boards normally have there own supply chains and avoid procuring from the companies above.

The prices can differ much and sometimes for very high volumes the prices can be very low compared with what one single component costs.

Sometimes surplus are found on eBay to low prices compared to those vending houses. It might also be rejects or counterfeit components.

 

If you know the component designation or number you can search at https://octopart.com/ to see availability at different distributors.

 

When looking for the very latest it is not always available at Mouser, Digikey... and sometimes you must have access to the manufacturer directly.

If you are working with projects they find interesting for the future they are often helpful.

 

Stefano - You talked about efficiencies of 40+% for UV-LEDs.

https://www.ultravio...dpost__p__39368

Can you please give any example of any component that can be bought?

The ones you show above have efficiencies closer to what I am used to see with around 30-35% efficiency

[Stefano]

Stefano - You talked about efficiencies of 40+% for UV-LEDs.

https://www.ultravio...dpost__p__39368

Can you please give any example of any component that can be bought?

The ones you show above have efficiencies closer to what I am used to see with around 30-35% efficiency

The LED I bought on eBay, https://www.ultravioletphotography.com/content/index.php/topic/3755-test-of-a-365-nm-led-on-ebay-powerful claimed 10 W of power consumption (which I confirmed) and 4-4.8 W of power output (which I can not tell if it is true, but it is surely powerful). The seller changed the LED to what looks to be an older one. Also, it was claimed to be a LG LED, but I don't know which model. I took some "macro" images of the dies, so you may be able to find it.

 

The other 365 nm LED I clearly remember to claim more than 40% efficiency is the Nichia NCSU276C. Steve talked about it here: https://www.ultravioletphotography.com/content/index.php/topic/3970-newer-convoy-s2-with-newer-365nm-uv-nichia-led

 

At the typical values Nichia reports, this LED exceeds 50% efficiency, and at 4.4 V, the maximum forward voltage this LED can have (according to the datasheet), you still have more than 40% efficiency. I don't know where you can buy this Nichia LED, there should be a place somewhere where you can (I guess).

 

365 nm UV LEDs exceeding 40% efficiency are rare. That Nichia LED is the only one I know that exceeds 50%, which is really a lot. As you said, the vast majority stays at 30-35%.

[ulf]

Thanks Stefano,

 

Then I am not that off.

 

Anyhow a change from 35% to 40%, or even 50% is significant in the numbers, but not that dramatic in practical usage.

 

Just as with photography we need at least one stop in increase to see a real gain in light-increase.

Then we are looking at a type of LED with higher power or some LED array.

 

If the radiation pattern is OK one stop light increase can be had by moving the lamp 30% closer

[colinbm]

I think the next goal is to find a broader output UVA LED or LEDS.

Like 320nm to 400nm for UVA coverage.

Certainly my next goal.

[Stefano]

I don't know if I already posted this, but this is a broadband UV LED that uses phosphors: https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.heraeus.com/en/hng/company_hng_1/press/archive_hng_press/heraeus_noblelight_introduces_the_first_broadband_uv_led_light_source_module_for_analytical_measurement.html&ved=2ahUKEwj5xaDQ-NnsAhWK3OAKHeP9DdgQFjAAegQIEBAB&usg=AOvVaw0wQoJyb6NlDzQcovl5KPJS&cshid=1603979532516

 

For now, we have to use multi-chip LEDs, like your project, and 340 nm LEDs are very inefficient.

[Stefano]

Anyhow a change from 35% to 40%, or even 50% is significant in the numbers, but not that dramatic in practical usage.

You are right, it won't be that dramatic, but think about this: 50/35 is a nice approximation of sqrt(2). This means that, keeping the same input power, you have half stop more light, and your battery will last the same amount of time. Half stop is not noticeable as you said, but it is better than nothing.

 

The biggest advantage is about heat generation: if you keep the output power the same, you have half the heat generated, since 0.7 = 0.5/1.4.

 

To be more precise, going from 35% to 50% efficiency, we have 0.65/0.35 = ~1.86 times less heat.

 

That Nichia LED is really efficient. Steve wasn't so lucky apparently, as the results he got didn't show any improvement. But at the average voltage, the efficiency is a staggering 55%.

[colinbm]

I don't know if I already posted this, but this is a broadband UV LED that uses phosphors: https://www.google.c...d=1603979532516

 

For now, we have to use multi-chip LEDs, like your project, and 340 nm LEDs are very inefficient.

 

Thanks Stefano, but only 1.5W

[Stefano]

Yes, that's quite weak, probably half a Convoy, but that's what we have. Still, 365-400 nm is a nice range, and shorter wavelengths wouldn't contribute much anyway. Adding a bunch (not one, a bunch) of 340 nm LEDs to a low-power setup (not more than 5 watts) could season your UV a bit, adding some false-green. Let's say you have a 365, 375, 385 and 395 nm LED setup. Each LED uses one watt of power and is 35% efficient. Then you have 1.4 W of UV between around 360 and 400 nm, with a good amount of violet. Each LED emits, in this example, 350 mW of light. The LED I linked in another topic has an output of 55 mW using 3 W. To have 350 mW, you need seven of them, using 21 W of power, while all other LEDs combined would only use 4 W of power.

 

With a more powerful setup, like your 90 W one that you built (and never completed I think, I don't remember) you would have needed roughly 150 of those LEDs, that alone would use 450 W of power. Yes, 450 W. You need a pretty big heatsink with fans to dissipate that heat, and... how much would the LEDs cost? In Italy, at ~60 € each, that would mean 9000 €. More than a UV-Nikkor.

 

As I said, LED technology improved massively in the last decades. Less than 40 years ago we didn't even have efficient blue LEDs, and they were still more expensive than other LEDs up to around the 2000s. Up to 10 years ago, we didn't have blue and green laser diodes (532 nm lasers use the non-linear properties of a crystal to literally "fuse" photons together, they are not direct-diode). UV LEDs are a recent innovation, and UV LEDs below 365 nm still have to improve a lot. Wait 10 years and you will see better LEDs.

[colinbm]

Thanks Stefano....... " Wait 10 years and you will see better LEDs " I hope I have that much in me & still UV savvy....?

[Stefano]

I hope too. We have to wait a while, but hopefully not too much.

[colinbm]

Thanks Stefano

[ulf]

Thanks Stefano, but only 1.5W

The 1.5W is the electrical input power.

The optical power is very very much smaller.

The fluorescence seams to be drivven with a 340nm LED.

they normally have very low efficiency.

 

The purpose for this device is not to illuminate for reflectance, but transmission where much less light is needed.

[Stefano]

I was wandering around on Mouser again, seeing the specs of other LEDs. I found one that is almost 50% efficient calculated on typical values.

 

Wavelength: 365 nm

 

Manufacturer: LED Engin

 

https://www.mouser.it/new/ledengin/led-engin-lz1-x0uv0r-led-emitters/

 

Datasheet: https://www.mouser.it/catalog/specsheets/LedEngin-08-01-2019-Preliminary%20LZ1-00UV0R_rev0.2_%2020190722.pdf

 

At 700 mA, the typical forward voltage is 3.8 V and the output power is 1.32 W. You can drive this LED at 1 A, but they didn't write the forward voltage at that current.

 

Input power: 2.66 W

Efficiency: 49.6%.

 

Seems now 50% efficiency is becoming the new standard, and high quality LEDs can be expected to be at least 40% efficient.

 

UV LEDs are probably the most efficient UVA light source. Fluorescent blacklights (not to be confused with mercury vapor blacklights) are around 25% efficient, and mercury vapor ones are a bit more efficient (I didn't find any information about their efficiency). Source: Wikipedia (https://www.google.com/url?sa=t&source=web&rct=j&url=https://en.m.wikipedia.org/wiki/Blacklight%23Fluorescent&ved=2ahUKEwj3iO_S29_sAhUHNOwKHZTdChgQ0gIoATAMegQIDBAJ&usg=AOvVaw3RaYEah6rFRssYB2qlBpb1&cshid=1604177847104).

 

We have to consider the little losses caused by filtering them with Wood's glass, as UV LEDs, as we know well, emit some visible light. Nichia UV LEDs are known to emit very little visible light.

 

Both fluorescent and mercury vapor blacklights are filtered with Wood's glass, so they could be more efficient without it (if one didn't care about visible light pollution).

[aphalo]

I have been using the LedEngin (now OSRAM) UV-A LEDs from some years, mostly the LZ1 series. They are available both as SMD (surface mounted devices) and mounted on star boards from Mouser and Digikey (the photographs are not always the right ones. Check the codes from the data sheets when searching in Mouser or Digikey).

 

The Nichia UVA and UVB LEDs are available from Lunitronix (https://www.lumitron...lor=Ultraviolet, https://www.ledrise....power-leds.html). Many of them they have available both as SMD devices and soldered on small break out boards.LEDiL makes some special lenses for the Nichia UV LEDs.

https://www.ledrise....sage=nichia--uv

 

Recently Roithner Laser has added some new interesting LEDs emitting at 325 nm and 340 nm, they are SMD devices. They are available with and without lenses. I have ordered some.

http://roithner-lase...uv/smd_340.html

http://roithner-lase...uv/smd_325.html

http://roithner-lase...uv/smd_310.html

As discussed by others in this thread efficiency is still quite low, but it has improved significantly and the prices gone down dramatically compared to 5 years ago.

 

I think the easiest way to drive these medium power LEDs is to use drivers like those from RECOM Power that allow both constant current (CC) and PWM (pulse width modulation). Series RCD24 for lower voltages and RCD48 if many LEDs are connected in series. https://www.mouser.f...e?Keyword=RCD48 https://www.mouser.f...e?Keyword=RCD24

 

There is one Chinese supplier that sells 365 nm LED arrays. I am not sure how good are the chips they use when assembling the arrays, but the largest array they sell has a total electric power of 200 W. I have bought other LEDs from them and they have been o.k.

https://www.leds-glo...m-led_c304.html

The optical output has minimum 40 W and maximum 60 W with no typical value given, so only about 25% efficiency.

https://www.leds-glo...nels-p-471.html

[colinbm]

Thanks Pedro

[Stefano]

Thanks Pedro for the links.