Zoom Optical Lens Group Layout for Aberration Correction
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Solution Overview
Problem
Conventional zoom optical systems for photographic and video cameras suffer from insufficient optical performance, particularly in correcting aberrations during zooming and focusing.
Innovation Solution
A zoom optical system comprising a first lens group with positive refractive power, a second lens group with negative refractive power, and a subsequent group with a focusing group having negative refractive power, where the distances between these groups change upon zooming, and the first lens group has a specific focal length ratio relative to the subsequent group's focal length, ensuring aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional zoom optical system is used, then the device can be manufactured with standard lens groups, but the optical performance is insufficient particularly in aberration correction during zooming and focusing
Solution Approach 1:
The optical system is divided into multiple lens groups (first lens group with positive refractive power, second lens group with negative refractive power, and subsequent groups including focusing groups) that can be independently positioned and adjusted. This segmentation allows each group to be optimized for specific aberration correction functions while maintaining overall system performance during zooming and focusing operations.
Solution Approach 2:
The patent employs dynamic positioning of lens groups where distances between the first lens group and second lens group, and between the second lens group and subsequent groups, change during zooming. The focusing group with negative refractive power is specifically designed to move dynamically during focusing operations, enabling real-time aberration correction across different focal lengths and focus distances.
2Speed
If the focus lens group is made small and lightweight for quick and silent autofocus, then the autofocus performance improves, but the barrel size is reduced which may compromise structural stability
Solution Approach 1:
The focusing group is designed with negative refractive power that acts as a counterweight to the positive refractive power of the first lens group. This counterbalancing arrangement allows the focus lens group to be made smaller and lighter while maintaining structural stability through the opposing refractive forces, enabling quick and silent autofocus without compromising mechanical robustness.
Solution Approach 2:
The patent utilizes changes in refractive power parameters and focal lengths to optimize the balance between size and stability. By carefully selecting the refractive indices and curvatures of lenses in the focusing group, the system achieves compact dimensions while maintaining sufficient structural rigidity for stable autofocus operation.
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 effectively corrects various aberrations during zooming and focusing, achieving excellent optical performance with a compact and lightweight design, suitable for digital cameras.
Implementation Method 1
a first lens group having positive refractive power; a second lens group having negative refractive power; and a subsequent group including at least one lens group
Data Source
AI summary
A zoom optical system comprises, in order from an object: a first lens group (G1) having positive refractive power; a second lens group (G2) having negative refractive power; and a subsequent group (GR) including at least one lens group. Upon zooming, distances between the first lens group (G1) and the second lens group (G2) and between the second lens group (G2) and the subsequent group (GR) change. The subsequent group (GR) comprises a focusing group (Gfc) having negative refractive power for focusing. The first lens group (G1) comprises a 1-1st lens that has positive refractive power and is disposed closest to the object. A following conditional expression is satisfied:0.2<f1/fR<0.85where,f1 denotes a focal length of the first lens group, andfR denotes a focal length of a lens component, in the subsequent group, closest to an image surface.