Zoom Lens Optical System Compact Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical systems for zoom lenses with high magnification struggle to achieve both size and weight reduction while maintaining sufficient optical performance.
Innovation Solution
The optical system comprises a specific configuration of lens groups with varying refractive powers, including a first positive lens group, a second negative lens group, a middle group, a focusing group, and a rear group, where the distance between adjacent lens groups changes with magnification, and the system satisfies specific conditional expressions to optimize performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the optical system uses a conventional zoom lens configuration, then sufficient optical performance can be achieved, but the size and weight of the lens barrel cannot be reduced further
Solution Approach 1:
The patent applies parameter changes by optimizing the focal length ratios between lens groups (specifically f1/(-f2) between 2.0-8.0 and Bfaw/fw between 0.05-0.60) and adjusting the movement distances of lens groups during zooming and focusing. These parameter optimizations enable compact design while maintaining optical performance. The conditional expressions define specific parameter ranges that balance miniaturization with image quality.
2Reliability
If the optical system uses a conventional zoom lens configuration, then sufficient optical performance can be achieved, but the size of the lens barrel cannot be reduced further
Solution Approach 1:
The patent optimizes structural parameters including the ratio of back focus to focal length (Bfaw/fw) constrained between 0.05-0.60, and the ratio of first to second lens group focal lengths (f1/(-f2)) between 2.0-8.0. These parameter changes enable compact lens barrel length while preserving optical performance through mathematically optimized group configurations.
Solution Approach 2:
The patent employs nested doll principle by arranging lens groups in a compact sequence where the first positive lens group, second negative lens group, middle group, focusing group, and rear group are nested along the optical axis. During zooming, inner lens groups move within the structure defined by outer groups, achieving variable focal length in a compact form factor.
3Length of stationary object
If the distance between lens groups is reduced for size reduction, then lens barrel size decreases, but optical performance and aberration correction deteriorate
Solution Approach 1:
The patent resolves this contradiction by establishing specific parameter ranges: the distance ratio between lens groups is constrained through the Bfaw/fw condition (0.05-0.60), and focal length ratios (f1/(-f2) = 2.0-8.0) are optimized. These parameter changes ensure that even in compact configurations, aberration correction remains effective within the defined ranges.
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 enables size reduction of the optical system while maintaining favorable optical performance, including improved correction of aberrations across various focal lengths.
Implementation Method 1
a first lens group having positive refractive power, a second lens group having negative refractive power, a middle group constituted by one or two lens groups and having positive refractive power
Data Source
AI summary
An optical system that achieves size reduction in a zoom lens with high magnification and has favorable optical performance, an optical apparatus, and a method for manufacturing the optical system are provided. An optical system OL included in an optical apparatus such as a camera 1 includes, sequentially from an object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a middle group GM constituted by one or two lens groups and having positive refractive power, a focusing group GF that is a lens group having negative refractive power and moves in an optical axis direction at focusing, and a rear group GR constituted by at least one lens group, distance between lens groups adjacent to each other changes at magnification change from a wide-angle end state to a telephoto end state, and the optical system OL satisfies a predetermined condition.