UV LEDs

[trixdropd]

For water-clear LEDs:  UV LEDs are UV.  Purple LEDs are purple.  There is a difference, and you cannot see it.  Do not look into UV lights.  If you don't have a spec sheet and/or don't know which is which, do not use them where visible. 

Well, I learn something new everyday. Thanks for the info!!

[outlier]

Hello all,


First post here. Hope no one minds my resurrecting this thread. I'd thought of starting a new thread, but thought that my question was germane to this topic, so it might be good to have this info in one place.

Anyway, what is the verdict on UV LEDs? Seems to me that few FX manufacturers use them and I thought it possible that this was based on a consideration concerning the safety of viewing these LEDs directly.

That said, I've seen those Halloween spooky village items sold seasonally in Christmas stores and elsewhere which have many UV-type LEDs.

How might one discern strict purple LEDs from UV? These sort of LEDs seem to be sold with "Purple" and "UV" used rather interchangeably.

I have seen some LEDs, nominally purple, that are dual color LEDs, combining red and blue in one package. There's someone in my town who drives around in one of those van/SUVs who has festooned his taillights with additional LEDs of this nature. At a distance, it appears that the blue color dominates or refracts over the red. (I'm a bit surprised he hasn't been pulled over by the PD, but this is TN after all, and vehicle lighting laws don't seem as strict here.  ) The LEDs in his taillights don't appear purple at all, really from any distance.

Is there even such a thing such as true purple LEDs? If memory serves correctly, I believe I saw something about white LEDs encased in purple plastic somewhere. I don't believe I've ever actually seen these though. Anyone know who sells these?

[danielzink]

From the first batch of "UV" led's I recieved (from one of the "well known" pedal parts companies) - it's been my "opinion" that they were referencing the color of the LED.....sort of like "ooooohhh..that ones purple-y....oooohhhhhh....that one's sorta voilet.....wow...that one is "ultra voilet".......

<shrug>

never got a tan off of 'em....never burned an eyeball....just a pretty sorta purple-y voilet color...

Dan

[outlier]

Some of the UV LEDs I've used have more of a faint color, something like a bluish periwinkle. I've never found an LED that was really purple.

I also have a Keeley Java Boost with purple LED; that's really just a pinkish color.

I did experiment with diffused dual-color LEDs, but all I'd manage to do is get an odd effect in which the light would refract one way red and the other blue. In other words, it'd be entirely red when viewed from one angle, completely blue from another angle. They did not mix. Which . . . is kind of a cool effect, but not what I was looking for.

These purple plastic LEDs, I'm going to have to look for these. Still can't find 'em. I have seen purple plastic LED strings. The LED—being a 10mm LED, inverted cone. These were at Target put out for sale for Halloween. Too big though, but looked decent.

[deadastronaut]

ive had uv leds before...they glow up luminous paint on my pedals so they give off uv,its weak but it does...

check this out.........expensive here too..rob.

http://www.maplin.co.uk/media/pdfs/N74AJ%20%20(ETG-5UV400-30).pdf

[linny1982]

These purple plastic LEDs, I'm going to have to look for these. Still can't find 'em. I have seen purple plastic LED strings. The LED—being a 10mm LED, inverted cone. These were at Target put out for sale for Halloween. Too big though, but looked decent.

you can get any colour leds you want buy using white water-clear leds and modeling tin spray clear colours. i use tamiya paints. you can even make smoke colours or custom ones with 2 light coats of different shades.

[outlier]

Would you believe I've actually tried this?   I occasionally build armor models. I have some clear paints and mixed some red and blue Gunze Sangyo clear paint. The problem, as I see it, is that white LEDs of course are actually blue LEDs with phosphors on the element in order that they glow white — albeit with a bluish tint.

So the problem was that even with a good purple mix, the color tilts heavily toward a blue, not purple at all.

A different way of illustrating this are those license plate bolts sold at truck stops. The purple bolts glow a nice purple as they have a small incandescent grain-of-wheat bulb in them. Take the purple lens and screw it on a white LED license plate bolt and you get . . . blue. Not purple at all.  

In a different experiment, I placed a red glass lens over a blue 10mm LED. Interesting thing: There was NO light at all emitted. Nothing. The red lens effectively filtered the blue wavelength completely out.