Microscope Objective Aberration Correction via Lens Group Segmentation
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Solution Overview
Problem
Conventional microscope objectives fail to correct axial chromatic aberrations and off-axis aberrations such as field curvatures and coma aberrations effectively, especially when achieving high performance over a wide wavelength region for a wide field of view.
Innovation Solution
A microscope objective design featuring a first lens group with positive refractive power and a second lens group, where the first and second lens groups have adjacent concave surfaces, including at least one cemented lens with negative refractive power and a single lens with positive refractive power, optimized to maximize axial marginal light ray height and satisfy specific conditional expressions for aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional microscope objectives are used, then the structure is simple, but axial chromatic aberrations and off-axis aberrations cannot be corrected effectively
Solution Approach 1:
The objective lens is divided into multiple lens groups (first lens group with positive refractive power, second lens group with negative refractive power, and third lens group) rather than using a single lens or simple configuration. Each lens group contains specific lens elements with defined refractive powers and dispersion characteristics, allowing independent optimization of different aberration types across the wide wavelength range.
Solution Approach 2:
Different lens elements within the objective are designed with specific local properties: the first lens group uses materials with particular partial dispersion ratios to correct chromatic aberrations, the second lens group uses negative refractive power to correct off-axis aberrations, and the third lens group optimizes the focal ratio. Each component is optimized for its specific function rather than using uniform design throughout.
2Adaptability or versatility
If a wide wavelength region is covered, then broadband observation is enabled, but chromatic aberrations increase
Solution Approach 1:
The patent specifies precise parameter ranges for lens materials including refractive indices (ne1, ne2, ne3) and partial dispersion ratios (θCt1, θCt2) to control chromatic aberration across the wide wavelength range from blue to near-infrared. By carefully selecting and optimizing these optical parameters, the design achieves broadband coverage while maintaining aberration correction performance.
Solution Approach 2:
The objective uses composite lens structures with different glass materials having complementary dispersion characteristics. The first lens group combines materials with specific partial dispersion ratios to correct axial chromatic aberrations, while the second lens group uses materials optimized for off-axis chromatic correction, creating a composite system that handles the full spectral range effectively.
3Area of stationary object
If a wide field of view is achieved, then observation area increases, but off-axis aberrations worsen
Solution Approach 1:
The patent addresses off-axis aberrations by introducing a second lens group with negative refractive power positioned between the first and third lens groups. This additional dimensional element in the optical path provides the necessary degrees of freedom to correct field curvature and coma aberrations across the wide field of view, which cannot be achieved with a simple single-group design.
Solution Approach 2:
The optical design dynamically balances different aberration corrections across the field of view by using the second lens group's negative refractive power to counteract off-axis aberrations while the first and third groups maintain focal ratio and axial correction. The system adapts its correction capability across different field positions rather than optimizing for a single point.
4Measurement precision
If high numerical aperture is maintained, then resolution is improved, but aberration correction becomes more difficult
Solution Approach 1:
The first lens group is designed with positive refractive power and specific material properties to preliminarily correct chromatic aberrations before light enters the subsequent groups. This preliminary correction establishes a foundation that makes it easier for the second and third lens groups to achieve high numerical aperture with maintained aberration performance, rather than attempting all corrections simultaneously at high NA.
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 objective effectively corrects chromatic aberrations and off-axis aberrations across a wide wavelength region, ensuring high performance with a wide field of view and maintaining a high numerical aperture, thereby enhancing image quality and resolution.
Implementation Method 1
a first lens group that has a positive refractive power and includes a first cemented lens; and a second lens group, the first lens group and the second lens group having concave surfaces adjacent to and facing each other
Data Source
AI summary
A microscope objective includes: a first lens group that has a positive refractive power and includes a first cemented lens; and a second lens group, the first lens group and the second lens group having concave surfaces adjacent to and facing each other. The second lens group includes: at least one lens component that has a negative refractive power overall; a second cemented lens; and a single lens having a positive refractive power. An axial marginal light ray height is maximized at the lens surface of the microscope objective that is the closest to an image. The microscope objective satisfies the following conditional expression:−0.38≤Fs/FC2≤0.38 (1)where FC2 indicates the focal length of the second cemented lens for an e line, and Fs indicates the focal length of the single lens for the e line.