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Science Forum Index » Optics Forum » good cheap aspheric lenses?
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| Guest |
 Posted: Wed Mar 26, 2008 7:48 am |
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I sometimes have a use for aspheric lenses, numerical aperture 0.5 or
higher, with focal lengths of about 10-30 mm - to collimate or focus
arc lamp beams, LED beams, etc. Edmund precision aspheres are good
but they cost about $200 each. Geltech (Light Path Technologies)
aspheres are good but too small (focal length < 8 mm if NA > 0.5).
Newport, Melles Griot, etc. sell cheap (approx. $20) glass aspheres,
but often the prescriptions are unavailable. And if the prescription
is available, when I ray-trace the lens in Zemax I usually find that
it has a huge amount of spherical aberration, and no combination of
conjugate ratio and window thickness makes the spherical aberration go
away. Maybe the published prescriptions are wrong, or maybe these
lenses were not designed for best on-axis performance but were
optimized for some other purpose.
Does anybody know who designed the cheap aspheres in the catalogs and
what he was thinking? Is there a source of aspheric lenses similar to
the Edmund precision aspheres, but manufactured to looser tolerances
and therefore less expensive? |
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| Richard J Kinch |
| Posted: Wed Mar 26, 2008 6:31 pm |
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Quote: Is there a source of aspheric lenses similar to
the Edmund precision aspheres, but manufactured to looser tolerances
and therefore less expensive?
http://surplusshed.com/ a few dozen selections. Many are top quality.
I've been pleased with this one in the past, although they may be down to
chipped-edge specimens by now:
http://www.surplusshed.com/pages/item/l3461.html |
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| chris |
| Posted: Fri Apr 25, 2008 12:41 pm |
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