The issues involved in the project
An optics formula designed to meet the rigorous demands of the specifications, taking on board the ease of manufacture and assembly of the lenses needed to be found. There needed to be thorough tolerancing of the optics solution once found, in order to study its soundness and thus find out whether it is achievable.
Service provided by Sophia Conseil
The Optics and Detection Centre’s engineers were able to take on the task of drawing up an optics solution which meets the specifications by:
- Designing the optics formula using CODE V and Zemax
- Taking the birefringence of the materials on board
- Carrying out the full tolerancing of the optics formula using CODE V (polishing) and Zemax (errors in measurement, errors in shapes, re-optimisation for compensation)
The Centre also analysed the ability of a catadioptric design to act as a system for the high aperture micro-lithography analysis by:
- Adapting the design to the application’s constraints (aperture, non-immersion, footprint)
- Optimising the system to improve resolution
- The solution we came up with meets almost all of the specifications, thus proving that a system of this kind is feasible (which was not a foregone conclusion). The tolerancing operations show that the system is sound enough to be potentially produced, although in spite of everything it does still require a re-optimisation stage and the use of a retardation plate..