Mar 30, 2022
Micro-Objective Design for Robotic Surgery

Robotic Surgery systems, and the surgeon using them, rely on the imaging quality of their optical system. Those high precision optics need to provide high-resolution images, while complying with challenging form factors – often less than 2mm diameter – as well as tight opto-mechanical constraints.
Good news! OpticStudio includes some easy-to-use, quick and efficient options to get it right.
Simply start with selecting “Contrast Optimization” in the optimization wizard and enter the spatial frequency of your detector (on the screenshots below, a frequency of a 100 lines/mm has been selected). This option uses the MECX operands instead of the MTFX ones: the contrast is computed at the specified spatial frequency only, using the phase difference at the exit pupil –it is way faster!
You can also consider manufacturability during the optimization! And potentially save quite some time later, if you realize you need to desensitize your system.
Option one is to simply check the “Improve manufacturing yield” option and specify the overall weight of the manufacturability versus the nominal performances. OpticStudio will then minimize the aberrations on each surface, during and without slowing down the optimization. The result is a system that is naturally more robust, and thus easier to manufacture. It can prove extremely useful at the early stages of your design.
Option two is to use the TOLR operand and use the actual sensitivity analysis of your system during optimization. This very rigorous approach, though it has speed impact on the optimization itself, can help you with the fine adjustments that might be needed towards the final steps of the design.
Then, when assessing the real-life performances of your system, our trusted Monte-Carlo statistical analysis is key. Not only can you check the yield curve for the optical performance criterion like MTF, but you can also save the worst offender. You can then open the corresponding system and get additional insight, using for instance the image simulation tool to have a better understanding of the performance shift.
The Ansys-Zemax ecosystem also offers additional options to model other aspects of the system like the sensor’s response, the depth-of field, the influence of thermal and structural effects, to name of few.
Check this webinar to set-up such a system: Micro-Optical Objective Design Strategies for Robotic Surgery -- Concept through Production
And the corresponding FAQ on our forum : [Webinar] Micro-Objective Design for Robotic Surgery [Q&A]
To try Zemax optical design software capabilities for yourself, request a free trial here.
Author:
Christophe Weisse / Senior Application Engineer
Zemax an Ansys Company