Zoom Lens System Aberration Control via Five-Group Segmentation
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Solution Overview
Problem
Existing zoom lens systems struggle to maintain favorable optical quality over the entire focal length range due to inappropriate refractive power balance and increased aberration fluctuations during zooming.
Innovation Solution
A zoom lens system comprising a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, and a positive fifth lens group, where at least the first, third, and fifth lens groups move in the optical axis direction during zooming, with specific refractive power ratios and configurations to optimize refractive power distribution and aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the refractive power in a lens group used for zooming is increased, then a large zoom ratio can be obtained within a predetermined movement amount, but aberration fluctuations that occur during zooming increase, making it difficult to attain a favorable optical quality over the entire focal length range
Solution Approach 1:
The zoom lens system is divided into five lens groups (positive, negative, positive, negative, positive) with each group having specific refractive power ranges. This segmentation allows the zooming function to be distributed across multiple groups rather than concentrated in one group, enabling a large zoom ratio while maintaining optical quality through coordinated movement of all groups.
Solution Approach 2:
The patent specifies precise refractive power parameters for each lens group (f1, f2, f3, f4, f5) with defined ranges and ratios. By carefully controlling these parameter changes and their relationships during zooming, the system achieves high zoom ratio while suppressing aberration fluctuations and maintaining favorable optical quality across the entire focal length range.
2Manufacturing precision
If the refractive power balance of lens groups is inappropriately set, then a high optical quality over the entire focal length range cannot be achieved
Solution Approach 1:
The patent establishes specific parameter ranges and ratios for the refractive powers of the five lens groups (f1, f2, f3, f4, f5) to achieve optimal optical quality. By defining these parameters with precise mathematical relationships, the system attains high optical quality while the complexity is managed through systematic parameter optimization rather than arbitrary configuration.
3Manufacturing precision
If a zoom lens system is configured with five lens groups, then additional freedom with regard to the movement of the lens groups is obtained compared to four lens groups, allowing suppression of aberration fluctuations during zooming
Solution Approach 1:
The zoom lens system uses five lens groups instead of four, providing additional degrees of freedom for movement control. This segmentation into more groups allows independent optimization of each group's refractive power and movement characteristics, enabling better suppression of aberration fluctuations during zooming while maintaining a compact overall structure.
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 system achieves favorable optical quality over the entire focal length range by suppressing aberration fluctuations and simplifying the lens barrel structure, reducing costs and manufacturing complexity.
Implementation Method 1
a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, and a positive fifth lens group, in that order from the object side
Data Source
AI summary
A zoom lens system includes a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, and a positive fifth lens group, in that order from the object side. Upon zooming from the short to long focal length extremities, at least the first, third and fifth lens groups move in the optical axis direction. The second lens group includes at least four lens elements. Each of the third, fourth and fifth lens groups includes a plurality of lens elements. The following conditions (1) and (2) are satisfied:1.60<f1/f5<2.46 (1), and−2.46<f4/f3<−1.80 (2),wherein f1, f3, f4 and f5 designate the focal lengths of the first, third, fourth and fifth lens groups, respectively.