Source for UVB (293-298nm) LEDs?

You wrote that you don’t take the pills. And I was a manager of a UVB clinic 20 years and have many patents on lamps and phototherapy. Anyway, goodby, try not to offend.

Nope, I think you misunderstood my post. :stuck_out_tongue:
I have said repeatedly that I DO take the pills. :thinking:
(I changed one of my posts above to make that more clear.)
Good day to you, too. :+1:
I think it’s best if we quit this discussion before it becomes an argument. :upside_down_face:

Hi All, I am interested in either building or buying (cost-effective) a sub 300nm (293nm minimum) LED or fluorescent UVB device (portable?). Ultraviolet B Light Emitting Diodes (LEDs) Are More Efficient and Effective in Producing Vitamin D3 in Human Skin Compared to Natural Sunlight | Scientific Reports It seems that if you can dial in the specific nm frequency (293-298nm), you don’t need much artificial light source time exposure to get significant Vit D skin production response - as compared to sunlight exposure (depends on your latitude, Sun zenith angle and weather/cloud conditions). So anyone have some straight forward options? You may not need so many watts - due to the specific nm Vit D production frequency efficiency. PS Any light detector device out there to also actually access the real nm number radiating from the light source?

Other than the smd packages that were linked earlier in the thread the closest uvb range I could find so far was through digikey in the 295nm range. DigiKey]https://www.digikey.com/en/products/detail/marktech-optoelectronics/MTSM295UV2-F1120S/15816636?s=N4IgjCBcoCwAxVAYygMwIYBsDOBTANCAPZQDa4AbAOxhwDMIAuoQA4AuUIAymwE4CWAOwDmIAL6EwATgAcUxCBSQMOAsTIgEjMRJAAmDQFcAbgAJMuACZMxQA

https://www.yingfengirled.com/category.php?id=1

These guys have some 295’s as well.

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I considered making a new thread, but figured I’d try necromancy on this one first.

There’s a study showing 293nm LEDs producing more vitamin d in skin than the sun. And having a narrow wavelength reduces the chances of skin damage etc.
Also seen studies showing how woefully inadequate our vitamin d testing is, how the supplements (which happen to be the same chemical as in rat poison) can cause vitamin d intoxication and yet you are still deficient at the same time, trigger weird problems with calcium and phosphorus… so I concluded its safer to get it from the sun. Theres also Sperti lamps, but I think we can do better.
The LEDs used were from Rayvio, but they apparrently ripped off Nitride Semiconductor from Japan, who sued them and won, and now Rayvio is no more.
I’ve seen some lamps with (supposedly) 293nm LEDs from like Alibaba, and individual LEDs from China, but don’t know how reliable these sources are. Prices aren’t great either.
I’m looking into methods of testing the LEDs output.
What I haven’t found is a source of any 293nm LEDs form Japan / Nitride.

Did you see this thread from 2 days ago? It’s not the exact wavelength you want but same purpose.

Shorter wavelength LEDs are expensive and relatively low powered compared to the tubes.

Unless you know how much UV you actually need, it’s hard to quantify the number of LEDs you’ll require.

Also bear in mind the UV LEDs are particularly susceptible to damage by heat, so you’ll need a good thermal contact and good heatsink (and/or active cooling)

Is anyone still exploring this? I’m interested in working on a product.

Note that the sunlight contains a relatively little proportion of the wavelength needed for vitamin D production. Even when the sun is at zenith, UVB light is only 1% of total irradiation, while UVA (which has no beneficial effects) is about 5% and blue and violet light (that are also bad for your skin at higher intensities) comprise another 10-15%. So if you match the total UVB exposure from a 293nm LED to that of the Sun (which comes to only about 13W/sq.m.), you will get almost all of the benefits without the vast majority of drawbacks.

I’ve got a few decent 310nm emitters and can get 295nm if it’s that important to get the wavelength just right. They’re pricey, ~$20-$25 USD/ea.

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Would love to take a look at the 295nm

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Try this link

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Here’s a spec sheet

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Convoy is selling 310 and 255 nm emitters by now, looks like they are from the company you linked, different model however. Pricey indeed! But that makes sense, this is very niche LED tech (and quite new, I think).

awesome, thank you! I sent them an email. If anyone else has made progress on this please let me know!

I placed an order with them just last week. They have a $40 shipping charge regardless of whether it’s for 1 emitter or 100, so purchasing just one doesn’t really make sense. I can add a 295 to my next order for you, but that won’t be for several months.

awesome. please let me know when you plan to place a new order.

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