scratched lens replacement ?

i tried to clean my lens but scratched it, i have diffraction lines through the beam now...
the module look like this:
DealExtreme: $15.95 Geniune New Wish 5mW Green Laser Module (5V)

the lens diameter is ~4mm
how to replace (or repolish?) the lens ? which lens should i buy and where ?

Edmund Optics carry lenses. You''ll need to determine the focal length of the scratched lens.
To do that you'll need a metric ruler or a non metric ruler and convert to metric. Also something to look at with the scratched lens like printed words.
Elevate the lens above the print until the image is as big a possible but not out of focus. Measure the height.
That will tell you the focal length.
Find a lens from Edmund Optics that matches as closely as possible.

edmund's lenses are too expensive, better to buy new module or even new pointer
in fact the exact module i have is here:
http://www.z-bolt.com/dpss-5-green-laser-module.html#
(this is the module inside this pointer: http://www.z-bolt.com/BTG2Splus-green-laser-pointer.html)
somenone know where i can buy one (and not a lot of 5) ?

is it necessary to have good quality lens ?
and i don't know what i need... aspheric, spheric, AR coated?
is it possible to pick the lens out of a an old CD reader ?

BKarim said:

edmund's lenses are too expensive, better to buy new module or even new pointer
in fact the exact module i have is here:
DPSS-5A, Class IIIa Green Laser Modules, < 5 mW for OEM, Research, FDA Legal
(this is the module inside this pointer: Z-Bolt® BTG-2S plus Green Laser Star Pointer - 5 Mile Range, 3 Finishes, Visible Beam)
somenone know where i can buy one (and not a lot of 5) ?

is it necessary to have good quality lens ?
and i don't know what i need... aspheric, spheric, AR coated?
is it possible to pick the lens out of a an old CD reader ?

Click to expand...

Look at the scratched lens and get one that looks like it. You should get one that's AR coated.

ok thank you