Immersion Objective Lens Spherical Aberration Correction
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Solution Overview
Problem
Existing immersion objective lenses for microscopes face challenges in effectively correcting spherical aberration, particularly at high numerical apertures and with large refractive index contrasts, often requiring long lenses and increased diameter, or complex mechanical constructions that are costly and prone to repairs.
Innovation Solution
A compact immersion objective lens design featuring a first, second, third, and fourth lens group with specific refractive powers, where the second lens group is movable along the optical axis to maintain a constant distance sum with the first and third lens groups, minimizing spherical aberration for a mean numerical aperture between zero and the nominal aperture, thereby maintaining a stable point spread function and coplanarity during adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a correction member with high refractive power is used to correct spherical aberration, then the corrective effect is improved, but the overall length and diameter of the objective lens increase
Solution Approach 1:
The patent employs a movable correction member (second lens group) that can be dynamically adjusted along the optical axis to correct spherical aberration. By making the correction member movable rather than fixed, the system achieves effective aberration correction without requiring excessive lens power, thereby maintaining a compact overall length while providing adaptive correction capability.
2Reliability
If multiple lens groups are moved to correct spherical aberration, then the corrective effect is improved, but the mechanical complexity increases
Solution Approach 1:
The patent extracts the aberration correction function from the entire lens system and isolates it to a single dedicated correction member (second lens group). By separating this specific function, the system achieves effective spherical aberration correction while minimizing mechanical complexity, as only one component needs to be movable rather than multiple lens groups.
3Device complexity
If a correction member with low refractive power is used, then the mechanical complexity is reduced, but the corrective effect decreases
Solution Approach 1:
The patent resolves this contradiction by making the correction member movable along the optical axis. This dynamic adjustment capability allows a lens group with moderate refractive power to achieve effective spherical aberration correction through position variation, eliminating the need for either high-power static lenses or multiple complex moving groups.
4Reliability
If the distance between lens groups is increased to achieve corrective effect, then the spherical aberration correction is improved, but the overall lens length increases
Solution Approach 1:
The patent maintains a constant sum of distances between the movable second lens group and its adjacent lens groups (first and third lens groups) while allowing the second lens group to move. This dynamic distance adjustment enables effective spherical aberration correction without increasing the overall lens length, as the movement is compensated by adjusting distances on both sides of the correction member.
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 solution provides a reliable, compact, and cost-effective correction of spherical aberration, suitable for confocal and lightsheet microscopy, with a stable point spread function and coplanarity, even with varying immersion fluids, while maintaining a short overall lens length and reducing mechanical complexity.
Implementation Method 1
the second lens group is moveable along the optical axis so as to achieve a corrective effect with respect to a spherical aberration, such that a sum of a distance between the second lens group and the first lens group and of a distance between the second lens group and the third lens group is constant
Implementation Method 2
a first lens group having positive refractive power, a second lens group having positive refractive power, a third lens group having negative refractive power and a fourth lens group having positive refractive power
Data Source
AI summary
An immersion objective lens for a microscope includes a first lens group having positive refractive power, a second lens group having positive refractive power, a third lens group having negative refractive power and a fourth lens group having positive refractive power disposed in this sequence from the object side. The second lens group is moveable along an optical axis so as to achieve a corrective effect with respect to a spherical aberration, such that a sum of a distance between the second lens group and the first lens group and of a distance between the second lens group and the third lens group is constant. The corrective effect of the second lens group is predetermined such that the spherical aberration is minimized for a light incidence that corresponds to a mean numerical aperture that lies between zero and a nominal aperture of the immersion objective lens.