Compact Microscope Objective Lens for Long Working Distance
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Solution Overview
Problem
Existing microscope lenses suffer from distortion, limited magnification, and short working distance due to their optical structure, which affects their performance and usability.
Innovation Solution
A microscope objective lens design comprising multiple lenses arranged in a specific sequence with defined focal length and thickness relationships, ensuring a compact structure with a large numerical aperture, low distortion, and long working distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If microscope lenses are composed of multiple lenses to achieve high magnification, then magnification is improved, but the lens length increases and working distance decreases
Solution Approach 1:
The patent employs a nested lens configuration where multiple lens groups are arranged concentrically along the optical axis. The first lens group with positive refractive power is positioned closest to the object, followed by subsequent groups with alternating refractive powers. This nesting allows high magnification to be achieved while maintaining a compact overall lens length by efficiently utilizing the optical path within each lens group.
Solution Approach 2:
The patent introduces a specific dimensional relationship by controlling the ratio of the sum of thicknesses of lenses in the last group to the total optical length (TTL). By maintaining this ratio within 0.05 to 0.15, the design optimizes the distribution of lens thickness across different dimensions, achieving high magnification without proportionally increasing the overall lens length, thus preserving working distance.
2Measurement precision
If microscope lenses are composed of multiple lenses to achieve high magnification, then magnification is improved, but working distance is reduced
Solution Approach 1:
The nested lens arrangement allows the optical power to be distributed across multiple compact groups rather than requiring a single long lens assembly. This enables high magnification to be achieved while keeping the front element position closer to the object, thereby maintaining an adequate working distance for practical microscopy operations.
Solution Approach 2:
The patent systematically optimizes multiple parameters including the refractive powers of individual lens groups, the spacing between groups, and the thickness ratios. By changing these parameters within specific ranges (e.g., the thickness sum ratio of 0.05-0.15), the design achieves a balance between magnification and working distance that overcomes the conventional trade-off.
3Ease of manufacture
If conventional optical structures are used, then manufacturing is simpler, but distortion occurs within microscopic range
Solution Approach 1:
The patent divides the optical system into multiple discrete lens groups with specific refractive powers (positive, negative, and alternating). Each group is designed to correct specific types of aberrations, with the first group having positive power and subsequent groups alternating. This segmentation allows distortion to be controlled through the cumulative effect of multiple specialized groups while maintaining reasonable manufacturing complexity for each individual group.
Solution Approach 2:
The patent employs composite lens design where lenses within each group may have different refractive indices and Abbe numbers. This composite approach allows the system to correct various chromatic and monochromatic aberrations simultaneously, reducing distortion across the microscopic field while maintaining manufacturability through the use of standard optical glass types.
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 lens design achieves smooth light transition, high magnification, and extended working distance, improving imaging quality and versatility for observing objects with uneven surfaces.
Implementation Method 1
A microscope objective lens includes a first lens, a second lens, a third lens having negative refractive power, a fourth lens, a fifth lens, a sixth lens, a seventh lens having positive refractive power, an eighth lens, a ninth lens, a tenth lens having positive refractive power, an eleventh lens, a twelfth lens, a thirteenth lens having positive refractive power, a fourteenth lens, a fifteenth lens, a sixteenth lens, a seventeenth lens, and an eighteenth lens
Data Source
AI summary
Disclosed is a microscope objective lens, whose focal length is f, total optical length is TTL, image height is IH. A combined focal length of the first and second lenses is f1_2, a focal length of the third lens is f3, a combined focal length of the fourteenth, fifteenth and sixteenth lenses is f14_15_16, a combined focal length of the seventeenth and eighteenth lenses is f17_18, an on-axis thickness of the seventeenth lens is d33, an on-axis thickness of the eighteenth lens is d35, and the microscope objective lens satisfies following relationships: −3.10≤f1_2/f3≤−1.80; 3.40≤f14_15_16/f≤7.00; 4.00≤f17_18/(d33+d35)≤120.00; and 0.08≤IH*f/TTL≤0.09. The microscope objective lens has a compact structure and excellent optical performance, meeting design requirements of low distortion, 20 times magnification, and long working distance.