Annular Axial Lens
The annular axial lens is defined by sweeping the cross section of a bi-aspheric lens around a decentered axis parallel to the axis of symmetry of the cross section. The cross section consists of two aspheric faces, each of which is a polynomial asphere. The cross section has the same shape as the Even Asphere Lens, see "Even Asphere Lens" . The cross section may however be decentered along the radial direction. The defining parameters are:
| Parameter # | Description | Face Name | Face # |
| 1 | The radius of curvature of the front face, use zero for flat. | Front | 1 |
| 2 | The conic constant of the front face. | Front | 1 |
| 3 | The radius of curvature of the rear face, use zero for flat. | Back | 2 |
| 4 | The conic constant of the rear face. | Back | 2 |
| 5 | The thickness of the cross section. The thickness must be large enough so that the edge thickness of the part is at least 0.001 times the center thickness. | Outside | 0 |
| 6 | The radial aperture of the cross section. | Inside | 3 |
| 7 | The radius of rotation from the local Z axis to the axis of symmetry of the cross section. This value must beat least 1% larger than the radial aperture of the cross section defined by parameter 6. | Outside | 0 |
| 8 | The decenter of the cross section within the lens aperture. Positive decenters shift the axis of the crosssection radially outward, negative decenters shift the axis radially inward. | NA | NA |
| 9 | Unused. | NA | NA |
| 10-17 | The front face coefficients . α1 through α8 | Front | 1 |
| 18-19 | Unused. | NA | NA |
| 20-27 | The rear face coefficients . α1 through α8 | Back | 2 |
Face Numbers: Outside face connecting the "maximum" apertures Face 0, front face Face 1, back face Face 2, inside face connecting the "minimum" apertures on the front and back Face 3.
Next: