Variable Magnification Optical System with Lightweight Focusing Group
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Solution Overview
Problem
Existing variable magnification optical systems are not lightweight enough for high-speed focusing operations and fail to effectively correct aberrations across varying magnification ranges.
Innovation Solution
A variable magnification optical system comprising a first lens group with positive refractive power, an intermediate group with negative refractive power, a focusing group with positive refractive power that moves upon focusing, and an image side group with positive refractive power, where the distances between these groups are varied to satisfy specific conditional expressions, optimizing the focal lengths and refractive powers to suppress aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the focusing group is made heavier to correct aberrations, then optical performance is improved, but focusing speed deteriorates
Solution Approach 1:
The optical system is divided into multiple lens groups (first lens group with positive refractive power, intermediate group with negative refractive power, focusing group with positive refractive power, and image side group with positive refractive power). This segmentation allows the focusing group to be optimized for speed while other groups handle aberration correction, resolving the contradiction between weight and performance.
Solution Approach 2:
Different lens groups are assigned specific functions: the first lens group handles wide-angle to telephoto zooming, the intermediate group corrects specific aberrations, the focusing group enables high-speed autofocus, and the image side group fine-tunes optical performance. This localized optimization allows each component to be designed for its specific purpose without compromising overall system performance.
2Adaptability or versatility
If lens groups are moved to vary magnification, then zoom capability is improved, but system complexity increases
Solution Approach 1:
The optical system employs dynamic movement of lens groups to achieve variable magnification. The first lens group moves relative to the intermediate group, and the intermediate group moves relative to the focusing group, enabling continuous zoom adjustment. This dynamic configuration provides adaptability while maintaining a relatively simple four-group 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 excellent optical performance, reduces the weight of the focusing lens group, and enables high-speed focusing operations while effectively correcting various aberrations across the wide angle to telephoto end states.
Implementation Method 1
a first lens group disposed at a most object side and having positive refractive power, an intermediate group disposed at an image side of the first lens group and having negative refractive power, a focusing group disposed at an image side of the intermediate group and having positive refractive power
Data Source
AI summary
Comprising a positive first lens group G1 disposed at a most object side, a negative intermediate group G2 disposed at an image side of the first lens group G1, a positive focusing group G3 disposed at an image side of the intermediate group G2, the focusing group G3 being moved upon focusing, and a positive image side group G4 disposed at an image side of the focusing group G3; upon varying magnification, a distance between the first lens group G1 and the intermediate group G2, a distance between the intermediate group G2 and the focusing group G3 and a distance between the focusing group G3 and the image side group G4 being varied; and a predetermined conditional expression being satisfied. Whereby a variable magnification optical system having excellent optical performance and a focusing lens group reduced in weight in order to attain high speed focusing operation, and others are provided.