March 07, 2019
As presented by Zemax Senior Computational Physicist Shawn C. Gay at this year’s Photonics West, TrueFreeform is a grid-based surface optimization of freeform surfaces in optical design.
Some lens design applications utilize parametric functions for representing freeform surfaces. Most common, perhaps, is a linear combination of Zernike functions. There is a downside to parametric approaches, though, namely that optimization of parameters typically forces the entire surface to change with each variable. In his talk, Gay spoke about a grid-based surface where sag contributions are specified on a rectangular grid. Optimizing on sag described in this fashion allows local influence on a specific region of the surface that is only as wide as twice the grid spacing.
Grid-based surface optimization in OpticStudio allows flexibility in designing freeform optical components that is not possible with traditional surface types. In his paper, Gay focuses on a corrector plate with the rear surface specified by a variable grid sag surface. The goal of the corrector plate is to correct for Wavefront error introduced by a Zernike phase surface. Gay described the tests and reported on findings, including the importance of constraints on the grid variables and techniques that improve the calculation efficiency.
< Return to blog
Search our blog
Sign up for our newsletter
Don’t miss out on key insights, best practices, and news from Zemax.
Sign up for our blog
Don’t miss out on key insights, best
practices, and news from Zemax.
Copyright © 2019 ZEMAX LLC. All rights reserved.