How to distinguish between Indoor and Outdoor LEDs?

[Bus Master]

What is the Min. illumination for a LED to be suitable for Outdoor/Sunlight use?

 

[Buriedcode]

Hi,

I'm no professional with LED's, so my opinion probably isn't worth much.
LED's are so cheap now-days I would say the brightest you can get. Although I picked up some ultra-bright red and blue LED's for £0.10 each (UK) and made the mistake of powering the little buggers up while looking at them, blind for about 20 minutes I'd say that standard LED's (60-120mcd) simply won't cut it, especially in bright sunlight, but you could always house them in a recessed (LED sunk in)bezel, on a black background. And also, the water clear LED's are good, because when they're off, they don't difuse other light sources, if mounted on a black bezel, they will simply look black. Whereas, difuse ones (coloured or colourless) will spread incoming light and reflect a little bit back.

So, just to re-iterate, heres some ideas:
-Water-clear package.
-Bezel, possibly recessed, and of dark colour.
-Superbright or hyper bright, maybe 500-1000 mcd, anything over that, and it becomes blinding.
-Green. Our eyes are most sensitive to luminance (difference between light and dark) at about 532nm, don't quote me on that. And this is green.

And there ya go, of course, the best way to find out, is to experiment . LED's are dirt cheap, and very easy to power, you just need a current limiting resistor.
Get a sunny day, and have a protoboard with different types lined up, and see what works for you.

As I said, I'm just spouting idea's, it's what I do here.

BuriedCode.

 

[atmaca]

I have no knowledege about the issue. But if it is so important for you you can grap some result by try end error

 

[Bus Master]

I mean, what is the minimum illumination for an LED to be seen in an outdoor display? specially in direct sunlight? how many millicandela (mcd) ?