Even Asphere Lens



The Even Asphere Lens object consists of 5 separate sections:

  1. An even aspheric shape front face.
  2. An even aspheric shape read face.
  3. An annular ring between the clear aperture of the front face and the edge of the front face.
  4. An annular ring between the clear aperture of the rear face and the edge of the rear face.
  5. A possibly tapered cylindrical surface connecting the edges of the front and rear faces of the lens.

The Even Asphere surface shape is defined by:

which is exactly the same sag formula as for the Even Asphere surface.

The total object shape is defined by 27 parameters:

Parameter # Description Face Name Face Numbers
1 The Clear Semi-Diameter to the clear aperture of the front face. Front 1
2 The Thickness of the lens at the center. NA NA
3-4 Unused. Side 0
5 The front face radius of curvature. Front 1
6 The front face conic constant k. Front 1
7-14 The front face coefficients α1 – α8. Front 1
15 The back face radius of curvature. Back 2
16 The back face conic constant k. Back 2
17-24 The back face coefficients α1 – α8. Back 2
25 The Radial Aperture to the edge of the front side of the lens. Side 0
26 The Clear Semi-Diameter to the clear aperture of the rear face. Back 2
27 The Radial Aperture to the edge of the rear side of the lens. Side 0

The reference point is the center of the front face of the lens.

*Face Numbers:

Face 1 = front face

Face 2 = back face

Face 0 = all other faces (lens edges, and regions between the clear aperture and the edge aperture)

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