On Feb 4, 2010, at 11:53 AM, Bob Blick wrote:

>> Cree announces a new LED product.....
>> http://www.cree.com/products/xlamp_mpl.asp
>>
>> The LED package is rated at a max of 1500 lumens.   My LCD projector
>> is rated at 700 lumens using an expensive bulb that puts out lots of
>> heat. Probably a Hi-pressure Xenon bulb.
>>
>> What is the comparison between these two light sources ?
>
> Mostly just that you are trying to compare them. There is very  
> little to
> compare otherwise. The LED you speak of is a string of LEDs in some
> package. The lamp in a projector creates a point source of light.

I dunno.  The Cree fits all those emitters onto a package of about 1cm  
on a side, so it's got a pretty high brightness density, or whatever  
you want to call it.  OTOH, your projector could be rating lumens at  
the output, while the Cree is Lumens from the light source.  Who knows?

If this goes on, I'd predict that someone comes out with an LED-based  
projector whose optics correct for the non-point-ness of the  
lightsource.  Fancy optics can pretty much be cast, these days, nearly  
as cheaply as less fancy optics?

On the third hand, projectors are like printers; sold cheap to tie you  
to expensive consumables...  :-)

BillW

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