Systematic design of microscope objectives
The modern microscope objective is the most sophisticated optical component in light microscopes, providing high contrast images with diffraction-limited resolution. The design of microscope objectives has been developed for over a hundred of years. However, after 1970s, the review of advanced application-oriented systems is limited, and the design principles are not clear to most optical designers who are not the specialist from a few microscope manufacturers. To subtract off the hidden assumptions during the historical development and turn back to the intrinsic building blocks of the high numerical aperture (NA) systems, in this work, a systematic analysis and synthesis approach for microscope objectives is worked out, which is not found in available literature. The microscope objective patents are collected worldwide. Concentrating on the standardized objectives with color correction at least in the visible spectrum, a large system database is built up within Zemax/OpticStudioTM. According to a systematic review of the historical development, new classifications of the modern microscope objectives are proposed to understand the system complexity. Thereby, systematic analysis of the systems can be conducted to decouple the impact of aberration correction, application and manufacturing requests. Based on the decoupled results, the building blocks and design principles of the modern microscope objectives are systematically analyzed and summarized. Lens modules are sorted with respect to the general optical power distribution and individual structural lens groups. The reasons for many commonly used complicated structures are explained. Utilizing the lens modules, the microscope objective design can be more systematic. Both the modification of existing systems and the synthesis of new structures are realized, which give optical designers new ideas or possible opportunities to keep away from the restriction of other patents.