Multi-Immersion Microscope Objective With Stable Working Distance
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Solution Overview
Problem
The design of microscope objectives that can accommodate a wide range of immersion media with varying refractive indices is challenging, especially for high numerical apertures and long working distances, leading to costly manufacturing and assembly requirements.
Innovation Solution
A microscope objective design featuring at least one concave mirror and an aspherical surface with an internal space filled by an immersion medium, where the aspherical surface is shaped to maintain a working distance variation of less than 1% and retain diffraction-limited image quality across different refractive indices, using minimally refractive surfaces to correct for spherical aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional refractive lens designs are used to achieve high numerical aperture and long working distance, then imaging performance is improved, but manufacturing cost and complexity increase significantly
Solution Approach 1:
The patent replaces refractive lens systems with a reflective catadioptric system using concave and convex mirrors. This substitution eliminates the need for complex multi-element lens assemblies required for high NA and long working distance, thereby reducing manufacturing complexity while maintaining imaging performance. The reflective surfaces inherently correct spherical aberrations and enable the desired optical characteristics without costly precision lens fabrication.
2Measurement precision
If microscope objectives are designed for specific immersion media with fixed refractive indices, then optical performance is optimized, but adaptability to different immersion media is reduced
Solution Approach 1:
The patent designs a catadioptric objective where the combination of concave and convex mirrors creates an optical system that maintains diffraction-limited performance across a wide range of immersion media refractive indices (1.33 to 1.70). The reflective surfaces and specific curvature ratios enable the objective to function universally with different immersion media without requiring redesign, achieving both optimized optical performance and broad adaptability.
Solution Approach 2:
The patent achieves adaptability by designing mirror surfaces with specific curvature ratios (|R1/R2| between 0.95 and 1.05) that remain effective across varying refractive indices. The optical system parameters are optimized to be insensitive to refractive index changes, allowing the same objective design to maintain performance with different immersion media by simply changing the medium rather than the optical components.
3Ease of manufacture
If standard spherical mirror surfaces are used, then manufacturing is simpler, but spherical aberrations degrade image quality
Solution Approach 1:
The patent employs spherical mirror surfaces with carefully controlled curvature ratios rather than complex aspherical surfaces. The concave and convex mirrors are designed with specific radius of curvature relationships that inherently correct spherical aberrations while maintaining manufacturability. This approach achieves diffraction-limited image quality without requiring difficult-to-fabricate aspherical geometries, balancing manufacturing simplicity with optical precision.
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 provides cost-effective performance across a wide range of immersion media with minimal aberrations, maintaining image quality and numerical aperture, suitable for various microscopy techniques.
Implementation Method 1
the aspherical interface is shaped such that the working distance of the immersion microscope objective varies by less than 1% when instead of a first immersion medium being arranged in said internal space a second immersion medium resides in the internal space that comprises a refractive index n that is increased or decreased with respect to the refractive index of the first immersion medium by at least 0.025
Implementation Method 2
A key challenge in the design of modern laser scanning microscopes is that there is a wide variety of immersion media that microscope optics need to be corrected for
Implementation Method 3
using minimally refractive surfaces to correct for spherical aberrations
Data Source
AI summary
The present invention relates to an immersion microscope objective (10) for inspecting a sample (S) in an immersion medium (M), comprising: at least one concave minor (3), at least one optical element (1) comprising an aspherical surface (2) facing the at least one concave minor (3), and an internal space (4) arranged between the at least one concave minor (3) and said aspherical surface (2), said internal space (4) being configured to be filled with an immersion medium (M) such that the immersion medium (M) contacts the at least one concave minor (3) and the aspherical surface (2). According to the present invention, the aspherical interface (2) is shaped such that the working distance (7) of the immersion microscope objective (10) varies by less than 1% when the refractive index n of said immersion medium (M) is increased or decreased by at least 0.025.