Microscope Objective Lens Diffractive Element Working Distance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional microscope objective lenses with high numerical aperture and well-corrected chromatic aberration often have insufficient working distance, affecting the operability of microscope apparatus, especially in observing fine patterns at high magnification.
Innovation Solution
A microscope objective lens configuration comprising a first lens group with a positive meniscus lens, a second lens group including a diffractive optical element, and a third lens group, optimized with specific refractive index and curvature conditions to achieve a long working distance and effective aberration correction across the visual field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high numerical aperture and well-corrected chromatic aberration are achieved using conventional objective lens designs, then the image quality and resolution are improved, but the working distance becomes insufficient
Solution Approach 1:
The objective lens is divided into three distinct lens groups with specific functions: the first group (with positive meniscus lens) handles light collection and initial focusing, the second group (with diffractive optical element) corrects chromatic aberration, and the third group (with negative lens) adjusts focus and working distance. This segmentation allows each group to optimize its function independently, resolving the contradiction between high image quality and sufficient working distance.
Solution Approach 2:
The patent employs specific refractive index ranges (n1≥1.8 for the positive meniscus lens) and curvature relationships ((−r1)/F between 0.5 and 4.5) to optimize the lens system. By carefully controlling these physical parameters, the lens achieves both high numerical aperture for image quality and extended working distance, eliminating the trade-off between these two performance aspects.
2Measurement precision
If the numerical aperture is increased to observe fine patterns at high magnification, then the resolution is improved, but the working distance is reduced
Solution Approach 1:
The diffractive optical element in the second lens group acts as an intermediary that corrects chromatic aberration introduced by the high numerical aperture. This intermediary component allows the system to achieve high resolution through high numerical aperture while maintaining sufficient working distance through the aberration correction and optimized lens configuration.
3Measurement precision
If chromatic aberration is well-corrected to achieve apochromatic performance, then the image quality is improved, but the lens structure becomes more complex
Solution Approach 1:
The patent combines multiple functions into the lens groups: the first group combines light collection and focusing, the second group combines chromatic aberration correction, and the third group combines focus adjustment and working distance optimization. This merging of functions into coordinated lens groups achieves apochromatic performance without excessive structural complexity.
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 configuration provides a microscope objective lens with high numerical aperture, apochromatic correction for chromatic aberration, and a sufficient working distance, ensuring excellent image quality even at the periphery of the visual field.
Implementation Method 1
a positive meniscus lens whose concave surface is directed to the object side
Implementation Method 2
a diffractive optical element having positive refractive power
Data Source
AI summary
A microscope objective lens includes, in order from an object side, a first lens group having positive refractive power, a second lens group having positive refractive power, and a third lens group having negative refractive power, and is configured such that the first lens group includes, on the most object side, a positive meniscus lens whose concave surface is directed to the object side, such that the second lens group includes a diffractive optical element having positive refractive power, and such that the diffractive optical element is arranged at a position closer to the image than a portion at which the diameter of a light flux passing through the first lens group and the second lens group is the larges.