Re: (fwd) Re: Isn't IR LED an oxymoron?

["Willem-Jan Markerink" <w.j.markerink@xxxxx>]

On 20 Jul 98 at 16:51, Peter Badcock wrote:

> I don't know of any IR LEDS which are visible to the naked eye, maybe they 
> exist?  However I suggest the term is an oxymoron, simply because the light from
> the IR LEDs are not visible.  My little Oxford Dictionary defines 'light' as 'a 
> natural agent that makes things visible'  So if the light isn't visible then 
> it's not light!
> Another reason I think that IR LED is a contradiction in terms is that one 
> leading opto electronics company which made these LEDs termed them 'IREDs'  
> which makes so much more sense........

It is a tad more confusing, below the first reply I posted to 
sci.optics:
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
FROM: w.j.markerink@xxxxx (Willem-Jan Markerink)
SUBJECT: Re: Isn't IR LED an oxymoron?
DATE: Fri, 17 Jul 98 17:44:54 GMT
NEWSGROUPS: sci.optics

In article <35AD0504.734C@xxxxxxxxxxxxxxxxx>,
   Don Stauffer <stauffer@xxxxxxxxxxxxxxxxx> wrote:
>Well, subject line says it  :-)
>

Might be true for a diode in specific (low intensity), but 'IR-light' is 
not an oxymoron AFAIK....once you crank up intensity, you can still see IR.
The common visible limit of 780nm more or less applies to daylight 
intensity and IR-pass filters. My literature on IR-Photograpy mentions this 
(non-linear) relation of 'visible limit vs intensity' more than once.
Of course, the absolute limit of this phenomena is indicated with the old 
joke 'you can see 1300nm, but only once in your life (at least with that 
eye)'....;-))
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

And one more, in the same thread:

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
FROM: w.j.markerink@xxxxx (Willem-Jan Markerink)
SUBJECT: Re: Isn't IR LED an oxymoron?
DATE: Fri, 17 Jul 98 21:59:15 GMT
NEWSGROUPS: sci.optics

In article <35AF4272.7A53@xxxxxxx>,
   "Gregory J. Whaley" <greg.whaley@xxxxxxx> wrote:
>I interpret your question to be "is infrared radiation light".  Is
>ultrasound acoustic energy "sound"?
>
>If infrared radiation falls on a tree in the forest, is it light?

You would be amazed how much IR goes *through* foliage, in contrast to 
visible light....
IR photographers often learn this the hard way....:-))
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
 

- -- 
Bye,

Willem-Jan Markerink


      The desire to understand 
is sometimes far less intelligent than
     the inability to understand


<w.j.markerink@xxxxx>
[note: 'a-one' & 'en-el'!]
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