Re: how to transfer energy through the metal wall ??

In sci.optics Chris Hodges <[EMAIL PROTECTED]> wrote:
> Ian Stirling <[EMAIL PROTECTED]> wrote in message news:<[EMAIL PROTECTED]>...
>> > Surely LEDs would be better (e.g. Lumileds 5W luxeon star in a range
>> > of colours).  That would bring the cost down.
>> 
>> The 5W luxeon will produce around 500mw of light, with a very large source
>> area.
>> IR laser diodes are quite efficiant and cheap, in the 0.5W size, and are
>> around 50% efficient as well as being much easier to couple to a fiber.
> 
> I had the glass rod in mind not the fibre, but that doesn`t really
> detract from your main point.
> 
> I thought the efficiency of the LEDs (not white) was rather better
> than that.  I also had some vague idea that a solar cell (assumed to
> be Si) would be losing efficiency into the IR (although I guess that
> wouldn`t hold for the 8xx nm ones), so you would want visible laser
> diodes, and you don`t get so much power for your money there.  I also
> thought that the LEDs would be easier to drive.

LEDs are a bit easier to drive.
You need to get quite far into the IR for Si to lose efficiancy.
White LEDs have around the same efficiency as halogen lights, maybe
5-10%.

AIUI, the best performers are some blue LEDs, with an efficiency of some
25%.


-- 
http://inquisitor.i.am/    |  mailto:[EMAIL PROTECTED] |             Ian Stirling.
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All I want is a warm bed, a kind word and unlimited power -- Ashleigh Brilliant.