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High Beam Divergence

B

BiasP11

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Jun 30, 2013
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I recently bought an IR diode with high beam divergence (12 x 28 degrees rectangular). Unfortunately, the module I own has a focal length of about two inches and a lens diameter of 1 inch. This means that about half of the light is not focused and instead scatters around inside the module.

I thought to move the lens closer by cutting off a piece of the heatsink, but that would result in a diverging beam when the diode is closer than the focal length.

To remedy that, can I add another convex lens?

How else can I solve this problem?
 





S

steve001

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Jun 3, 2007
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Two ways.
1. Replace this lens with a larger diameter longer focal length lens
2. Buy or construct an IR beam expander
 
Cyparagon

Cyparagon

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Sep 12, 2007
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Yes, you could add another convex lens. I would put it in a standard module if I were you though. 2 inch focal length is not laser material.
 
R

Roam

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Nov 21, 2011
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The laserbeam expanders are usually, I think, a convex and a concave lens put together. Since the concave is negative the whole system would be afocal, this is useful esp if you have a high power beam.
 
S

steve001

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BiasP11 said:
I recently bought an IR diode with high beam divergence (12 x 28 degrees rectangular). Unfortunately, the module I own has a focal length of about two inches and a lens diameter of 1 inch. This means that about half of the light is not focused and instead scatters around inside the module.

I thought to move the lens closer by cutting off a piece of the heatsink, but that would result in a diverging beam when the diode is closer than the focal length.

To remedy that, can I add another convex lens?

How else can I solve this problem?
Click to expand...

Can you post some photos of this unit?
 
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