Volume 8, Issue 5 - Systematic design of microscope objectives

In the three connected papers, a systematic analysis and synthesis approach for microscope objectives is introduced. To subtract off the hidden assumptions in the historical development of the microscope objective lenses and extract the intrinsic lens modules, a large objective database is implemented including most of the patented systems for standardised applications. Based on the systematic analysis of the database, in Part I, a general review of the development history is given. A systematic classification method is proposed with respect to the five most significant parameters. According to the review and classification, the impacts of applications, manufacture and technology considerations are systematically analysed and summarised. Details of the lens modules will be discussed in Part II, and the synthesis approach utilising the lens modules will be introduced in Part III.

Based on the microscope objective database and systematic classification introduced in Part I, the Zones 1–4 objective lenses are systematically analysed in this paper to extract the building blocks. All the definitions and terms are based on the preceding paper. The lens modules utilised in the front, middle and rear groups are investigated by reliable aberration evaluation tools with robust and accurate raytracing. Thereby, the aberration correction principles are summarised, from which 29 lens modules are well sorted with respect to their decoupled aberration correction functionalities. Furthermore, some intrinsic relations between the aberration-related lens modules and the impact of applications or the consideration of manufacturing and technology are also discussed. Utilising the lens modules, system modification and synthesis examples shall be given in Part III.

In this paper, the lens modules used in the Zones 1–4 microscope objectives, which have been summarised in Part II, are utilised to create new structures. Both the modification of available systems and the synthesis of new system structures from basic building blocks are introduced. Moreover, design principles used under four special cases are introduced in this paper, including very-low-magnification Zone 5 objectives, very-high-magnification Zone 6 objectives, objectives with correction function (CORR) and objectives with diffractive optical elements, which were not systematically discussed in Part II. All the definitions and terms are based on the preceding papers.