The Binary 2 surface has the same sag shape as an even asphere, but it does not support the use of irregularity operands directly. You could try to have a Binary 2 surface with no thickness or material but with sag parameters exactly matching a subsequent supported surface like Standard or Even Asphere. A pickup solve in this case, though usually discouraged, would be appropriate as the surfaces represent a single physical surface and should change in unison.

Hi Kevin, thank you for the reply. Before I read your response I had tried something similar to what you suggested, but in reverse. However, the change in criterion shown in the tolerancing run output was zero, so it appears that the tolerance I applied was effectively ignored. I used a Zernike Fringe Sag surface with zero thickness (but still with the same lens material) immediately followed by the Binary 2 surface. The Binary 2 surface had pickups for radius, conic, and aspheric terms to the Zernike surface. In the tolerance data editor I used TPAR to apply a tolerance to parameter 25 of the Zernike surface which is Z11 for spherical aberration. So, I tried to apply spherical aberration to the Binary 2 surface, but it appears to have had no effect. Note that by using the Zernike Fringe Sag surface it is easy to compute the coefficient values needed to apply a specific amount of aberration. Tolerancing aspheric or binary coefficients directly does not allow for a straightforward conversion to the amount of error applied (as far as I know). That is why I did not put the Zernike surface after the Binary 2, with pickups to the Binary 2. Any other suggestions?

Hi Jennifer,

We typically recommend one of two options for tolerancing irregularity on a Binary 2 surface:

1. Use TPAR to directly tolerance the Binary 2 parameters. This would probably require an external calculation of the RMS error you want to see using the Binary 2 sag equation as given in the Help System file The Setup Tab...Editors Group (Setup Tab)...Lens Data Editor...Sequential Surfaces (lens data editor)...Binary 2 (sequential surfaces, lens data editor). This would be a similar method to how TEZI applies across a Zernike Standard Sag surface.



2. Use a Zernike Fringe Phase surface to apply irregularity. The Knowledgebase article 'Tolerancing surface irregularity using a phase surface' discusses how this phase surface can be used to apply A(B/C) irregularity, as given by ISO 10110 standards. Additionally, the author of this KBA - Erin Elliott - presented this topic at a recent OpticsTalk. The forum thread for that talk is found here: OpticsTalks: Tolerancing A (B/C) Irregularity per ISO. It contains the relevant slides and code.

Since you are already using Zernike terms to apply the irregularity, I think the second option will be best. If you continue to see 0% contribution on your tolerance report after working through these tutorials, let us know! It might be a good idea for us to get a look at the file in that case. 

Best,

Allie