Safety of specific LEDs

[nonlocality]

Hi all,

A bit of a silly question, i'm doing a test board for work to evaluate a chip we taped out, and for the lulz of it I want to throw on some power indicator LEDs. I've always been partial to the color purple and found these LEDs on digikey.

AA3528VRVFS/A

They are 66 mW, 250 milicandela indication LEDs, the fact they are in the category indicators makes me think they are probably safe to use...but i'm a bit nervous. I have some friends in photonics who have some real horror stories involving lasers they work with, can anybody comment on whether they think the given part is safe or not?

I contacted the manufacturer as well and am waiting for a response on that end.

Thanks in advance.

 

[KlausST]

Hi,

It is different to a laser, because with a laser there is a very narrow beam, even after many meters the laser point is very small. The whole laser energy is at this small spot.

But with a LED the beam is relatively wide, and with increasing distance the area of the beam increases with the square of the distance.
Thus the intensity for a given area inside the beam decreases with the square of the distance. ... = 1/(d^2)

Your LED may harm the eyes only when the LED is very close to your eyes and you continously stare into the beam.
Don't try this.

With a viewing angle if 120° your eyes need to be max 5mm (maybe less) away from the LED to get almost full energy of light.
With half a meter distance only 1/10,000 of this energy may hit the sensible area of your eyes.

(Because of the narrow beam a Laser may give still 100% of the light energy to your eyes, even at 10m distance)

I can't imagine that the LED can cause damage to your eyes at a distance if 0.5m.

Klaus

 

[Audioguru]

The color purple is almost the frequency of ultra-violet rays which cause sunburn and damage to the the lenses and retinas of your eyes.

 

[prairiedog]

I use 3528 SMT LED's for indicators as they are large and popular in car dashboards. I find Digikey has nothing special, aside from the expensive Cree parts.

Kingbright has specialty colours, and eBay/Ali is full of vendors selling "ice blue" "pink" "purple" LEDs.

The purple ones are actually UV, almost a blacklight, so I don't use them. They are hard on the eyes.
The "pink" ones actually look purple but have a little UV I think, because I see blue fringing. They use phosphor though.