Microscope Objective Design for Chromatic Aberration Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current microscope objectives fail to adequately correct chromatic aberrations in the short-wavelength region near the h-line (404.06 nm), leading to color shifts during fluorescence observation in multiwavelength excitation, which compromises the credibility of data obtained in bio-related research.
Innovation Solution
A dry microscope objective design featuring two lens groups with cemented doublet lenses, optimized to correct various aberrations from short-wavelength to near-infrared regions by carefully arranging cemented and single lenses to control ray bending and height, satisfying specific numerical aperture, focal length, and Abbe number conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional microscope objectives are used, then the structure is simple, but axial chromatic aberrations in the short-wavelength region near the h-line cannot be adequately corrected
Solution Approach 1:
The objective lens is divided into multiple lens groups (first lens group with positive refractive power and second lens group with negative refractive power), each containing specific lens elements (cemented lenses and single lenses) with defined positions and powers. This segmentation allows independent optimization of each group to correct chromatic aberrations across the wavelength range from 400 nm to near-infrared while maintaining manageable structural complexity
Solution Approach 2:
Specific lens elements are positioned at precise locations within the lens groups, with the first cemented lens having its negative lens closest to the object and the second cemented lens having its negative lens farthest from the object. Each lens element has specific refractive power and material properties (Abbe number) optimized for its local position to correct chromatic aberrations in specific wavelength regions, particularly the short-wavelength region near the h-line
2Illumination intensity
If the numerical aperture is increased to improve imaging quality, then the light-gathering ability increases, but the correction of chromatic aberrations becomes more difficult
Solution Approach 1:
The patent specifies precise parameter ranges for the lens elements, including the refractive power of the first and second cemented lenses, the Abbe numbers of the negative lenses (40 ≤ νd(−) ≤ 60), and the ratio of air-gap distances to negative lens thickness (0.5 ≤ a/b ≤ 2.0). These parameter optimizations enable the system to maintain high numerical aperture for improved light-gathering ability while effectively correcting chromatic aberrations across the wavelength range from 400 nm to near-infrared
3Adaptability or versatility
If multiple wavelength excitations are used to improve fluorescence observation capability, then the versatility increases, but color shifts occur due to uncorrected chromatic aberrations
Solution Approach 1:
The objective lens is designed to function across a broad spectral range from 400 nm (violet) to near-infrared wavelengths, accommodating multiple wavelength excitations for fluorescence observation. The lens groups and elements are configured to provide universal correction of chromatic aberrations, enabling the single objective to serve multiple excitation wavelengths without significant color shifts, thereby improving versatility while maintaining color accuracy
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 axial chromatic aberrations and other optical errors across a wide wavelength range, ensuring high-quality imaging and data credibility in fluorescence observations.
Implementation Method 1
Each of the first cemented lens, the second cemented lens, and the third cemented lens is a cemented doublet lens that combines one positive lens with one negative lens
Implementation Method 2
The microscope objective effectively corrects axial chromatic aberrations and other optical errors across a wide wavelength range
Data Source
AI summary
An objective includes the first and second groups. The first group includes the first cemented lens with a concave surface facing the object side, the first and second single lenses having positive power, and the second cemented lens with a concave surface facing an image side. The second group includes the third cemented lens with a concave surface facing the object side and a third single lens having positive power. Each of the cemented lenses combines one positive lens with one negative lens. The objective satisfies the following expressions.0.31≤NA<1 (1)2.2≤H/f≤3.3 (2)0<a/b≤1.2 (3)Here, NA is a numerical aperture, f is a focal length at e-line, H is a distance from an object surface to a lens surface closest to an image, a is the sum of air-gap distances in the first group, and b is a thickness of a negative lens in the second cemented lens.