Four-Group Microscope Objective Lens for High-NA Aberration Control
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Solution Overview
Problem
Existing microscope objective lenses with high magnification and large numerical aperture struggle to effectively correct various aberrations such as chromatic aberration of magnification, spherical aberration, coma aberration, and curvature of field.
Innovation Solution
A microscope objective lens configuration comprising a first lens group, a second lens group with positive refractive power, a third lens group with a concave surface facing the image side, and a fourth lens group with a concave surface facing the object side, with specific conditional expressions defining the relationships between lens distances and properties to optimize aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high magnification and large numerical aperture are achieved, then imaging capability is improved, but aberration correction becomes difficult
Solution Approach 1:
The objective lens is divided into multiple lens groups (first through fourth lens groups) with different functions. The first lens group handles initial light convergence, the second corrects spherical aberration, the third corrects chromatic aberration, and the fourth corrects coma aberration. This segmentation allows each group to be optimized for specific aberration correction while maintaining high magnification and numerical aperture.
Solution Approach 2:
Each lens group is designed with specific local optical properties tailored to correct particular types of aberrations. For example, the second lens group uses specific refractive index and dispersion characteristics to correct spherical aberration, while the third lens group uses different material properties to correct chromatic aberration. This local optimization of optical properties enables comprehensive aberration correction across the entire lens system.
2Manufacturing precision
If multiple lens groups are added to correct aberrations, then aberration correction is improved, but device complexity increases
Solution Approach 1:
Multiple aberration correction functions are merged into a compact four-group configuration. Rather than adding separate correction lenses for each aberration type, the invention integrates spherical aberration correction, chromatic aberration correction, and coma aberration correction into a unified four-lens-group structure, reducing overall system complexity while maintaining comprehensive correction capability.
Solution Approach 2:
Each lens group serves multiple functions simultaneously. For example, the second lens group not only corrects spherical aberration but also contributes to the overall magnification and focal length of the system. The third lens group corrects chromatic aberration while also affecting the numerical aperture. This multi-functionality reduces the need for additional dedicated correction elements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed lens configuration achieves excellent correction of chromatic aberration, spherical aberration, coma aberration, and curvature of field, maintaining high magnification and large numerical aperture, with adjustable aberration correction for varying cover glass thickness.
Implementation Method 1
a first lens group, a second lens group having positive refractive power, a third lens group having a concave surface facing an image side, and a fourth lens group having a concave surface facing an object side, the lens groups being arranged in order from the object side along an optical axis
Data Source
AI summary
A microscope objective lens (OL) is constituted by a first lens group (G1), a second lens group (G2) having a positive refractive power, a third lens group (G3) having a concave surface facing the image side, and a fourth lens group (G4) having a concave surface facing the object side. The first lens group (G1) is constituted by a plano-convex positive lens (L101) having a flat surface facing the object side, and a negative lens (L102) and satisfies the following conditional: 1.8<H1/H2<3.5 and 1.3<DLe/H2<3.5, where: H1 is the distance between the optical axis and the light ray most separated from the optical axis in the second lens group (G2), from among light rays emitted from an object (OB) on the optical axis; H2 is the distance between the optical axis and the light ray most separated from the optical axis at a lens surface on the image side of a final lens (Le); and DLe is the length of the final lens (Le) on the optical axis.