Microscope Objective Lens Groups for High NA and Long WD

The objective lens is divided into multiple lens groups (first through sixth lens groups) with different functions. The first lens group handles initial convergence, the second and fourth groups correct spherical aberration, the third group controls field curvature, and the fifth and sixth groups correct coma aberration. This segmentation allows each group to be optimized for specific parameters, achieving high NA while maintaining long WD.

Each lens group has specifically designed local optical properties: meniscus lenses with concave surfaces facing the object side in the first, fourth, and sixth groups; cemented lenses with specific refractive index combinations in the second, fifth, and sixth groups. These localized optical characteristics enable precise control of light paths to achieve both high resolution and long working distance simultaneously.

The third lens group is specifically designed as a positive single lens with optimized refractive index to control field curvature independently. This local optimization allows the field of view to be widened without compromising the high numerical aperture achieved by other lens groups, resolving the trade-off between resolution and field of view.

The multiple lens groups collectively perform multiple functions: the first, second, and fourth groups correct spherical aberration; the third group controls field curvature; the fifth and sixth groups correct coma aberration. This multi-functional design enables the objective to achieve high resolution, wide field of view, and long working distance simultaneously.

The objective is segmented into six lens groups with specific functions. The first lens group provides strong initial convergence to maintain high NA, while the subsequent groups correct various aberrations introduced by the extended working distance. This segmentation allows the system to achieve both long WD and high NA.

The patent employs parameter changes in the form of specific conditional expressions that define the relationships between focal lengths and refractive indices of different lens groups. By optimizing these parameters, the system achieves the desired balance between working distance and numerical aperture.