On 6/30/05, Robert Rolf <Robert.Rolf@ualberta.ca> wrote:
> PicDude wrote:
> 
> > Some time ago, I tried to get a couple clean thin lines with laser pointers to
> > form a crosshair on my drill press for drilling PCB holes (and other things).
> > Could not get the lines clean though.  Perhaps you might?
> 
> To make this work you need to cast a shadow from a small aperature.
> Laser pointers have lousy beam shape unless corrective lenses are used.

Does this really work?  I would think the aperture would have to be a
long ways away (relatively) from the laser source to actually cast a
sharp shadow.  Even though the beam shape is lousy, it is still fairly
collimated, so most of the divergent rays would pass through the
aperature unless it was really tiny, in which case, you lose a lot of
your energy.  It would work better to have a really bright (energy
inefficient, but cheap) light source and use that to cast the shadow.

Don't most of the shaped laser pointers use a lens (as you said) to
provide the shape to the output, whether that's a smiley face or
"happy birthday?"

Bradley

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