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 | | From: | Spagyrique | | Subject: | Re: Focussing Lens without Spherical Aberration | | Date: | Tue, 11 Jan 2005 15:28:11 -0500 |
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 | Thank you for the info / correction.
"BC" wrote in message
> A single element lens can be completely corrected for third order coma
> and all orders of spherical aberration with a single aspheric surface.
The other being...spherical, planar?
By corrected for all orders of SA do you actually mean stigmatic on axis for
a source at infinity?
> In a fast lens there will be higher order coma, which can be
> effectively corrected with a bi-aspheric design. This is the basis of
> the objective lenses used in all CD/DVD players.
Concerning the CD/DVD lenses how do they take care of the large SA caused by
the plastic layer, especially at high NA? By introducing a certain amount of
SA of the opposite sign?
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