Infinity-Corrected Microscope Objective for Chromatic Aberration Control
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Solution Overview
Problem
Existing objectives for industrial applications face challenges in achieving high resolution, wide field of view, and long working distance while effectively correcting aberrations, particularly lateral and axial chromatic aberrations, which are exacerbated by the use of non-cemented lens components.
Innovation Solution
The objective is configured with a first and third lens group having positive refractive power and a second lens group comprising a pair of cemented lenses with concave surfaces facing each other, adhering to specific conditional expressions to optimize aberration correction, including the use of cemented lenses to enhance chromatic aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If non-cemented lens components are used, then assembly flexibility is improved, but chromatic aberration correction deteriorates
Solution Approach 1:
The patent applies cemented lenses where multiple lens components are permanently joined together using optical cement. Specifically, the second lens group includes a cemented lens formed by joining a negative lens and a positive lens, and the third lens group includes another cemented lens. This merging of components eliminates air gaps between lenses, thereby correcting chromatic and lateral chromatic aberrations that would otherwise be exacerbated by non-cemented configurations.
2Measurement precision
If high numerical aperture is achieved, then resolution is improved, but working distance deteriorates
Solution Approach 1:
The patent divides the objective lens into multiple distinct groups (first, second, and third lens groups) with specific functions. The first lens group (positive power) and third lens group (positive power) work together to achieve high numerical aperture for resolution, while the second lens group (negative power) with cemented lenses controls the optical path to maintain adequate working distance. This segmentation allows independent optimization of resolution and working distance parameters.
Solution Approach 2:
The patent employs specific parameter ranges including conditional expressions for focal lengths, distances between lens groups, and refractive indices. By carefully controlling these parameters—such as the negative power of the second lens group and the spacing between groups—the system achieves high NA while preventing the working distance from becoming excessively short.
3Productivity
If wide field of view is achieved, then throughput is improved, but aberration correction deteriorates
Solution Approach 1:
The cemented lenses in the second and third lens groups act as intermediaries that correct aberrations across the wide field of view. The cemented configuration provides continuous refractive index transitions that compensate for off-axis ray deviations, thereby maintaining aberration correction quality even when the objective is designed for a wide field of view to improve throughput.
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
This configuration allows for favorable correction of aberrations, enabling a wide field of view and long working distance while maintaining high resolution, reducing manufacturing costs and errors due to fewer lens components.
Implementation Method 1
a first lens group having positive refractive power, a second lens group including a pair of lens components having concave surfaces facing each other, and a third lens group having positive refractive power
Data Source
AI summary
An objective includes a first lens group having positive power, a second lens group including a pair of lens components having concave surfaces facing each other, and a third lens group having positive power, and the pair of lens components is cemented lenses, and the following conditional expression is satisfied.0.20≤d2/L≤0.5 (1)where d2 is a distance between a surface situated closest to an image side in a first lens component and a surface situated closest to the object side in a second lens component, the first lens component being a lens component situated on the object side and the second lens component being a lens component situated on the image side of the pair of lens components. L is a distance between a surface situated closest to the object side and a surface situated closest to the image side in the objective.