Even Asphere

Rotationally symmetric polynomial aspheric surfaces are described by a polynomial expansion of the deviation from a spherical (or aspheric described by a conic) surface. The even asphere surface model uses only the even powers of the radial coordinate to describe the asphericity. The model uses the base radius of curvature and the conic constant. The surface sag is given by:

Note that the coefficients have units. The coefficients are entered in the corresponding parameter columns, as shown in the following table.

PARAMETER DEFINITIONS FOR EVEN ASPHERE SURFACES

Parameter #	Definition
1 - 8	α1 - α8

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• Extended Asphere