Expert Zone

What sets First Time Right apart from others?

Visualizing N-dimensional spaces proves challenging, even for basic systems with two or three lenses. Such spaces often contain numerous local minima, resulting in a complex landscape characterized by hills and valleys determined by design variables/parameters. There is a risk of drawing too simplified conclusions from these basic cases and just extrapolate to higher dimensions. It is tempting to assume that more complex cases merely feature an extension of the same hill-and-valley merit-function topography into a higher N-dimensional space.

In practical designs, however, the merit function exhibits much greater intricacy compared to basic counterparts. This results in the presence of finer structural details within the parameter landscape, also featuring smaller irregularities. For example, the peak of a mountain might contain locals dip capable of capturing the design and confining it within a highly unfavorable local minimum. Any local or global optimization approach can only attempt to explore parts of this very obscure N-dimensional space in a finite amount of time and at relatively high computational cost. So far, we have not even talked about real-world constraints on top of the nominal optical design parameters. In that sense, ‘First Time Right’ is radically different.

The core concept behind our proprietary ‘First Time Right’ approach is to radically reduce the dimensionality of the parameter space. In a nutshell, our all-analytic calculations provide the surfaces shapes ensuring that all aberrations are simultaneously minimized and balanced per aberration order. This drastic reduction of the initial N parameter space dimensions greatly enhances the speed and efficiency of local and global optimization as well as machine learning-based approaches. Consequently, we can perform an unprecedented in-depth search of this reduced sub-parameter space. Finally, as the design parameters have been largely reduced to a minimum, we can incorporate real-world constraints, tolerances, and costs right from the start. 

Exemplary visuals of design parameter spaces

A monochromatic f/8 two-lens objective

This basic optical system with 50 mm focal length already features multiple local minima with similar performance. For further simplification, both the lens thicknesses and the distance in-between have been kept constant.

An achromatic f/8 doublet lens design

With a 50 mm focal length, only six considered standard glasses and all thicknesses fixed, there are many local minima. Even worse, a considered broader glass library leads to a large numbers of material combinations.

'First Time Right' f/3 three-freeform mirrors

This design requires only six alignment variables – in stark contrast to over forty directly calculated surface coefficients.
It highlights FTR’s efficient reduction of parameter space dimensions for a very thorough design landscape evaluation.

Selected references

Realizing ‘First Time Right’ designs of imaging systems using off-the-shelf lenses

A. Madrid-Sánchez, H.Thienpont, F. Duerr

SPIE Optical Systems Design Conference, 130191A (2024)

Fermat meets PanDao: cost-efficient lens design

F. Duerr, O. Faehnle, E. Langenbach, H. Thienpont

SPIE Optical Systems Design Conference, 1301909 (2024)

Freeform imaging systems: Fermat’s principle unlocks 'first time right' design

F. Duerr, and H. Thienpont

Light: Science & Applications Vol. 10, Article number: 95 (2021)

Automated freeform imaging system design with generalized ray tracing and simultaneous multi-surface analytic calculation

Y. Nie, D. R. Shafer, H. Ottevaere, H. Thienpont, and F. Duerr

Optics Express Vol. 29, Issue 11, pp. 17227-17245 (2021)

First Time Right freeform optics: a systematic and highly effective tool to design imaging systems from scratch

F. Duerr, and H. Thienpont

Photonics Views, 18: 52-56 (2021)

Optical design of first time right imaging systems

F. Duerr and H. Thienpont

Optical Design and Testing XII, 123150E (2022)

 

Starting point generation for imaging systems under practical constraints

F. Duerr, O. Faehnle, and H. Thienpont

International Optical Design Conference, 127980R (2023)

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