Immersion Microscope Objective Lens Groups for Deep Tissue Imaging
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Solution Overview
Problem
Current microscope objectives for multi-photon excitation face challenges in achieving high numerical aperture and correcting aberrations while maintaining a sufficient working distance and imaging performance, especially for deep tissue observation in biological samples.
Innovation Solution
The immersion microscope objective is designed with a specific configuration of lens groups, including a first lens group with positive refractive power, a second lens group with cemented lenses to minimize aberrations, and a third lens group that converts divergent light to convergent and then parallel beams, satisfying conditional expressions to optimize working distance, focal length, and numerical aperture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a microscope objective is designed with large numerical aperture to increase light density at focal position, then multi-photon excitation efficiency is improved, but working distance becomes insufficient for deep tissue observation
Solution Approach 1:
The objective lens is divided into three distinct lens groups with specific functions: first lens group (positive refractive power) for initial light convergence, second lens group (cemented lens) for aberration correction, and third lens group for final beam shaping. This segmentation allows each group to optimize specific parameters independently, achieving both high numerical aperture and sufficient working distance.
Solution Approach 2:
Different regions of the optical path are assigned different optical characteristics: the first lens group provides strong convergence for high light density, the second lens group (with cemented lens) provides aberration correction for imaging quality, and the third lens group provides controlled divergence for extended working distance. This local optimization of optical properties resolves the contradiction between light density and working distance.
2Length of moving object
If infrared light with long wavelength is used to reduce Rayleigh scattering and reach deeper positions, then penetration depth is improved, but aberration due to refractive index fluctuation increases
Solution Approach 1:
The second lens group acting as an intermediary between the first and third lens groups provides specialized aberration correction. The cemented lens in this group specifically compensates for refractive index fluctuations in biological tissues, enabling deep penetration of infrared light while maintaining image quality through precise aberration management.
Solution Approach 2:
The objective is optimized for specific infrared wavelengths (1000-2000 nm) with adjusted lens parameters including refractive indices and curvatures. The conditional expressions define specific ranges for working distance, focal length, and numerical aperture that are optimized for infrared multi-photon excitation, changing the optical parameters to match the requirements of deep tissue imaging.
3Manufacturing precision
If multiple lens groups are added to correct aberrations and improve imaging performance, then image quality is improved, but device complexity increases
Solution Approach 1:
The second lens group uses a cemented lens configuration where multiple elements are joined together, merging their aberration correction capabilities into a single integrated unit. This merging approach achieves superior aberration correction while minimizing the number of separate optical elements and reducing overall system complexity compared to using fully separate lens groups.
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 enables high-resolution, wide-area observation with reduced aberrations, allowing for deeper tissue penetration and improved imaging performance in multi-photon excitation microscopy.
Implementation Method 1
a lens component that has a positive refractive power and changes a divergent light beam incident from the second lens group to a convergent light beam, two lens components that change the convergent light beam to a divergent light beam, and a lens component that has a positive refractive power and changes the divergent light beam to a parallel light beam
Implementation Method 2
the second lens group includes a second cemented lens
Data Source
AI summary
An immersion microscope objective includes, a first lens group, a second lens group, and a third lens group, wherein the first lens group has a positive refractive power and includes a first cemented lens disposed nearest to the object side in the first lens group, the second lens group includes a second cemented lens, the third lens group includes a lens component that has a positive refractive power and changes a divergent light beam incident from the second lens group to a convergent light beam, two lens components that change the convergent light beam to a divergent light beam, and a lens component that has a positive refractive power and changes the divergent light beam to a parallel light beam and emits the parallel light beam, and the following conditional expressions (1) is satisfied:60 mm2≦d0×f×NAo≦500 mm2 (1).