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 Laser Pointer Forums - Discuss Laser Pointers Contact lens for your laser?

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12-30-2008, 05:24 PM #1
 Class 1M Laser Join Date: Oct 2008 Posts: 169 Rep Power: 9
New_Reverie
Class 1M Laser

Join Date: Oct 2008
Posts: 169
Rep Power: 9

I am working on cutting down the size of a green laser module at the moment and a thought came to me. Currently most green modules use 2 lenses to create a low diverging beam. But are two lenses needed? The answer is not really.

Because of the nature of lasers we want to take light that is diverging from our diode and turn it so that all emissions are parallel. Contact lenses are designed to do this exact same process in reverse. They take parallel light rays and focus them to a point.

Although laser light is not emitted from a single point it does travel out in a linear way that allows you to mathematically extrapolate it to a single point source. This is simply done by finding the divergence of the beam and then deciding how far away the lens will be placed from where the beam mimics a point source, this will be your focal length.

At this point all that needs to be calculated is the power for the lens measured in dioptres, which is the inverse of the focal length.

Price: I've seen hard contact lenses for around \$30-35. With power ranging from +/-(20 to .12), which equates to +/- 5cm to several meters

For an example of this i wanted to bring up jayrobs review of one of sandstone's high powered lasers.
http://www.laserpointerforums.com/fo...num=1227558208

The main problem with these lasers is poor divergence as shown here
Quote:
 Divergence: I put my goggles on and measured the dot at 40' distance. Using a black piece of plastic. The dot size was 4.5mm at 1', and 28mm @ 40'.
using these measurements the focal point is ~ 6.4 ft behind the aperture. 6.4 ft is ~ 1.95 meters. This would equate to a power of .51 dioptres.

So for another \$35 the poor divergence of this laser may be correctable to almost 0 divergence!

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