LEDs and eye safety

Heh. ;-)

I wonder how it's pronounced?

Cheers! Rich

">>

Didja ever wonder why "abbreviation" was such a long word?

A town in Wales, as I recall.

Just like it's written !!

Jim

Well, eventually I expect there will be visible light LEDs capable of causing eye damage just because a great deal of power will radiate from a very small area. However, I don't expect that will be for a few years.

I read in sci.electronics.design that "Rich, Under the Affluence" wrote (in ) about 'LEDs and eye safety', on Tue, 4 Oct 2005:

Difficult to render in ASCII-art.

I read in sci.electronics.design that Chris Carlen wrote (in ) about 'LEDs and eye safety', on Mon, 3 Oct 2005:

There MAY be some intermediate distance where the total energy is a maximum. But certainly, at the distances normally applicable to traffic signals and eyes, the energy is minimal.

Safety stuff would also apply to people installing and maintaing the signals who might well get a lot closer.

who

Only if all the LEDs were angled to one spot, guessing LEDs in traffic signals are 20 degree or so.

Perceived hazard is power density with tiny high power source being imaged on retina. Traffic light is loads of tiny sources.

Adam

So is yours - a bit. If the eye is on-axis. If the LEDs produce a 20 degree light cone, then the incident power to the eye will be pretty much the same until the eye gets far enough from the source that the apparent size of the source cannot grow any further. The apparent size of the source starts out at some 2mm, if your eye is pressed against it, and grows as a 40 degree cone, as you remove your eye. This assumes small sources, closely packed, with real ones, with real beamshapes, and finite size, the function will be more lumpy.

The sun is in violation of several directives and therefore it must be shut down immediately.

I am constantly amazed by how many expensive (and copyright, and legally mandatory) standards one must comply with in order to sell a product. I can't say that I have noticed any consequent improvement in the usefulness of products either. Why anyone would try to manufacture products these days is completely beyond me.

Chris