Microscope Objective Lens Groups for Stable Aberration Correction
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Solution Overview
Problem
Conventional objectives face challenges in achieving high performance across a wide wavelength and visual field range due to significant variations in aberrations such as spherical, axial chromatic, and coma aberrations with lens movement, especially when the thickness of cover glass, specimen refractive index, and immersion liquid refractive index change.
Innovation Solution
The objective is designed with a first lens group having positive refractive power, a second lens group that moves along the optical axis, a third lens group with two or more cemented surfaces, and a fourth lens group with specific surface orientations to correct aberrations. This configuration includes a second lens group that reduces light divergence, a third lens group that corrects axial chromatic aberration, and a fourth lens group that corrects chromatic aberration of magnification and astigmatism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high NA objective is designed to achieve wide field of view and high resolution, then imaging performance is improved, but spherical aberration varies significantly with changes in cover glass thickness, specimen refractive index, and immersion liquid refractive index
Solution Approach 1:
The patent employs a movable lens component (22) that can shift along the optical axis in response to changes in cover glass thickness, specimen refractive index, or immersion liquid refractive index. This dynamic adjustment mechanism allows the lens to compensate for varying optical conditions, maintaining stable spherical aberration correction while preserving high NA performance for wide field of view and high resolution imaging
2Reliability
If a movable lens mechanism is added to correct spherical aberration variation, then aberration stability is improved, but device complexity increases
Solution Approach 1:
The patent utilizes changes in physical parameters (refractive index, cover glass thickness) as triggers for lens movement. By designing the lens assembly to respond to these parameter changes through optical forces or mechanical coupling, the system achieves automatic aberration correction without requiring complex active control mechanisms, sensors, or power supplies, thus maintaining reliability while limiting complexity increases
3Ease of manufacture
If conventional lens configurations are used, then manufacturing is simpler, but aberration correction performance across wide wavelength and visual field range is insufficient
Solution Approach 1:
The patent employs cemented lens components where multiple lens materials with different refractive indices and dispersion characteristics are bonded together. This composite lens structure enables simultaneous correction of multiple aberration types (spherical, chromatic, coma) across wide wavelength and visual field ranges. The cementing process, while adding some manufacturing complexity, uses standardized optical cements and procedures that remain practically feasible
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 design effectively stabilizes aberration correction across varying conditions, ensuring high numerical aperture performance and reducing aberrations like spherical, axial chromatic, and coma aberrations, even with changes in cover glass thickness.
Implementation Method 1
a positive lens having a convex surface directed to the image side and a meniscus lens having a concave surface directed to the object side are cemented
Implementation Method 2
a third lens group having two or more cemented surfaces
Data Source
AI summary
An objective includes a first lens group, a second lens group configured to move along an optical axis, a third lens group having two or more cemented surfaces, and a fourth lens group including a lens having a convex surface directed to the object side, a lens having a concave surface on an image side, a lens having a concave surface on the object side, and a lens having a convex surface on the image side. The first lens group has three or more lens components including a lens component in which a positive lens having a convex surface on the image side and a meniscus lens having a concave surface on the object side are cemented on outermost object side, and none of the three or more lens components is a cemented lens in which a negative lens is disposed closer to the object side than a positive lens.