Compact Zoom Lens Layout for High Magnification Autofocus
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Solution Overview
Problem
There is a demand for a zoom lens that is compact in size, offers high magnification, and is advantageous for autofocus, while maintaining high optical performance.
Innovation Solution
A zoom lens configuration comprising a first lens group with positive refractive power, a middle group with changing inter-group spacings, and a final lens group, with a focusing group in the middle group that moves during focusing, adhering to specific conditional expressions to optimize size, magnification, and autofocus performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the zoom lens is designed to be compact in size, then the total length is reduced, but the magnification capability deteriorates
Solution Approach 1:
The zoom lens is divided into multiple lens groups (first lens group, second lens group, third lens group, fourth lens group, fifth lens group, and sixth lens group) with different refractive powers. This segmentation allows each group to contribute differently to the overall optical performance, enabling high magnification while keeping the total length compact through optimized group configurations and spacing.
Solution Approach 2:
The patent employs movable lens groups that can change their positions and spacing dynamically during zooming and focusing operations. The second, third, and fourth lens groups are configured to move relative to each other, allowing the system to adjust its optical characteristics in real-time to achieve high magnification at various focal lengths while maintaining a compact form factor.
2Adaptability or versatility
If the magnification is increased, then the imaging capability is improved, but the autofocus performance deteriorates
Solution Approach 1:
The fifth lens group is specifically designed as a focusing group that moves independently during autofocus operations. This dynamic configuration allows the focusing group to adjust the focus position without affecting the overall magnification capability, thereby maintaining both high magnification and good autofocus performance simultaneously.
Solution Approach 2:
Different lens groups are assigned different functions: the first and sixth lens groups provide positive refractive power for overall focusing, while the second, third, and fourth lens groups with negative refractive power specifically contribute to zooming and maintaining focus during magnification changes. This local specialization ensures that autofocus performance is not compromised by high magnification settings.
3Ease of operation
If the lens groups are moved to achieve focusing, then the autofocus capability is improved, but the aberration fluctuations increase
Solution Approach 1:
The patent carefully controls the movement parameters of the focusing group (fifth lens group) and adjusts the spacing between lens groups to minimize aberration fluctuations. By optimizing the displacement distance and position of the focusing group during autofocus operations, the system maintains stable optical performance while achieving effective autofocus capability.
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 solution achieves a compact zoom lens with high magnification and improved autofocus capabilities by controlling lens movements and refractive powers, reducing fluctuations in aberrations and total length, and enhancing optical performance.
Implementation Method 1
a first lens group G1 having a positive refractive power, a middle group GM, and a final lens group GE
Data Source
AI summary
A zoom lens consists of, in order from the object side, a first lens group that has a positive refractive power, a middle group that includes a plurality of lens groups in which the spacings between adjacent lens groups change during zooming, and the final lens group. The focusing group that moves during focusing is disposed in the middle group. The zoom lens satisfies predetermined conditional expressions.