Re: The reflector problem

[T3D John Bercovitz <bercov@xxxxxxxxxx>]

George writes:
> Sorry, I missed the discussion on Lambertian Surfaces and viewer relectors.
[...]
> I have been concerned about the light fall off at the ends of a viewer
> and was thinking that a cylindrical surface (semicircle seen in projection)
> with the bulb at the center, is the geometry needed to avoid light
> fall off.  Is this correct? [...]
 
I've sent George the entire log of our immortal words.  George, 
see John Vala's analysis - the cylindrical surface is correct.  
However, looking in my red button and in my Star D, keeping John's 
words in mind, I see that the surfaces are indeed cylindrical, but 
for some reason the lamp is not at the center of curvature but is 
closer to the surface of the cylinder than that.  Perhaps the 
viewers' designers found that same light fall off problem you're 
talking about.  Also, the surfaces may not be perfectly Lambertian 
which is what John's theoretical analysis was based on.
 
If anyone needs any back digests or can't get pictures from Joel's 
or Bob's site with his particular computer access, please let me 
know and I will send whatever you're missing to you.  Partial 
internet access musn't be a stumbling block to these discussions.
 
John B 
 
PS to BobH: I didn't know Lambert had square feet; what was he?  A duck?


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