Elongating light spot 1

[htsmech]

I am trying to illuminate a surface with light from a light guide. At the distance I am using, the spot is 7mm dia, but the surface is 7x28. Can I use a plano-concave cylindrical lens to stretch the spot 4:1 in one direction? If so, how can I calculate the object distance given the focal length and elongation? If not, is there a better alternative? Space is very limited. I can handle the 4:1 reduction in intensity, but not the 16:1 reduction from expanding the beam in both directions.

Thanks,

Steve

 

[nbucska]

What do you do with the light? do you sense it, look at it,
reflect it to a sensor ?

You can find equations in any physics book.

<nbucska@pcperipherals.com>

 

[IRstuff]

Why not just illuminate from the side?

TTFN

 

[cev]

IRStuff has the best idea, if your problem permits. The next-best solution for limited space is a holographic diffuser.

POC (

http://www.poc.com/)

sells light-shaping diffusers with elongation primarily along one axis. These spread angles are most likely suited to your needs:

40ºx0.2º
30ºx5º

CEV

 

[htsmech]

Duh!

I will try illuminating it from the side.

Thanks,

Steve

 

[opticsman]

Hi
first ignore the azimuth which is correct as your lens will have no optical power in that direction. second work out your magification (or reduction) . This is the ratio of guide dimension to 16mm , image dimension. From basic optics image to object distance ration is the same. so using the lens formaula 1/v+1/u = 1/f (You know u/v ) you can work out your focal length in the power azimuth.
opticsman.