Zoom Lens with Segmented Third Group for High Magnification
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Solution Overview
Problem
Conventional zoom lenses with a magnification ratio of 5 times or less face challenges in achieving higher magnification while maintaining a compact and high optical performance, especially in achieving a longer focal length at the telephoto end and a wider angle of view at the wide-angle end.
Innovation Solution
A zoom lens configuration comprising five lens groups with specific refractive powers, where the third lens group has an object side portion and an image side portion with the widest air interval, and the second lens group moves along the optical axis for magnification changes, including a vibration-compensation group to correct image blurring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a zoom lens with a relatively simple lens configuration is used, then the zoom lens can be made compact, but the magnification ratio is limited to 5 times or less
Solution Approach 1:
The third lens group is divided into an object side portion group and an image side portion group with the widest air interval between them. This segmentation allows independent optimization of each subgroup's optical properties while maintaining overall compactness, enabling higher magnification ratio without significantly increasing lens size.
Solution Approach 2:
The second lens group is designed to move along the optical axis during magnification change, creating a dynamic zoom mechanism. This movement enables the lens to achieve variable magnification ratios beyond 5 times while maintaining a relatively simple and compact overall configuration through coordinated motion of lens groups.
2Adaptability or versatility
If the focal length is increased to achieve higher magnification ratio, then the telephoto end performance is improved, but the lens size increases
Solution Approach 1:
The object side portion group and image side portion group of the third lens group are positioned with the widest air interval between them, creating a localized region with optimized optical properties. This local quality enhancement allows the system to achieve higher magnification and longer effective focal length without proportionally increasing the overall lens volume.
3Device complexity
If a simple lens configuration is used to reduce complexity, then manufacturing is easier, but optical performance and aberration correction are compromised
Solution Approach 1:
Dividing the third lens group into object side and image side portion groups with the widest air interval between them enables targeted aberration correction in each subgroup. This segmentation maintains relatively simple overall configuration while achieving high optical performance through localized optimization of each segment's optical properties.
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 allows for a high magnification ratio while maintaining compactness and high optical performance, effectively correcting various aberrations across the zoom range and enabling a wider angle of view at the wide-angle end.
Implementation Method 1
a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having negative refractive power
Data Source
AI summary
A zoom lens includes, in order from an object side, a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, and a negative fifth lens group, and magnifies by changing an interval on an optical axis between adjacent lens groups. The third lens group includes an object side portion group arranged on an object side with a widest air interval in the third lens group and an image side portion group arranged on an image side of the object side portion group, and the second lens group moves along the optical axis at a time of magnification change. The object side portion group and the image side portion group each include a positive lens, a positive lens, and a negative lens arranged in order from the object side. Further, an imaging device including the zoom lens is provided.