Variable-Magnification Optical System Aberration Control
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Solution Overview
Problem
Conventional variable magnification optical systems experience significant variations in aberrations during zooming and lack effective measures for correcting camera shake-induced aberrations.
Innovation Solution
A variable magnification optical system comprising a specific configuration of lens groups with varying distances between them, including a vibration reduction lens group, and satisfying certain conditional expressions to control aberrations, ensuring effective correction of coma, curvature of field, and spherical aberrations across different focal lengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional variable magnification optical systems are used, then zooming function is achieved, but variation in aberrations upon zooming is large
Solution Approach 1:
The patent applies dynamics by making the optical system adaptable through zooming while controlling aberration variations. The fourth lens group is specifically designed with positive refractive power and is moved during zooming to dynamically adjust the optical path, allowing the system to maintain acceptable aberration levels across different focal lengths despite the changing configuration
Solution Approach 2:
The patent changes optical parameters by specifying that the fourth lens group has positive refractive power and controlling the distance relationships between lens groups during zooming. These parameter changes enable the system to achieve variable magnification while suppressing aberration variations through careful optical design
2Ease of operation
If vibration reduction lens group is added to correct camera shake, then camera shake correction is achieved, but variation in aberrations upon correcting camera shake is not effectively suppressed
Solution Approach 1:
The patent applies universality by designing the fourth lens group with positive refractive power that serves multiple functions: it participates in zooming operations and simultaneously helps suppress aberration variations during camera shake correction. This multi-functional design allows the system to handle both zooming and vibration reduction without significant aberration degradation
Solution Approach 2:
The patent uses composite optical design by combining multiple lens groups with different refractive powers (first negative, second positive, third negative, fourth positive) to create a composite optical system. This composite structure allows the fourth lens group to contribute to both zooming and aberration control during camera shake correction, effectively suppressing variation in aberrations
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 suppresses aberration variations during zooming and provides robust correction for camera shake, maintaining optical performance across wide-angle and telephoto end states.
Implementation Method 1
a fourth lens group (G4) having positive refractive power
Implementation Method 2
at least one single lens of the second lens group is a vibration reduction lens group that is moved so as to have a component in a direction perpendicular to the optical axis
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A variable magnification optical system includes, in order from the object side, a first lens group G1 having negative refractive power; a second lens group G2 having positive refractive power; a third lens group G3 having negative refractive power; and a fourth lens group G4 having positive refractive power; upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group G1 and the second lens group G2 being varied, a distance between the second lens group G2 and the third lens group G3 being varied, and a distance between the third lens group G3 and the fourth lens group G4 being varied; at least one single lens of the second lens group G2 being a vibration reduction lens group VL which is moved so as to have a component in a direction perpendicular to the optical axis; and predetermined conditional expression being satisfied, thereby providing the variable magnification optical system capable of attaining superb optical performance with making variation of various aberrations small and coping with variation of various aberrations upon correcting a camera shake, an optical apparatus equipped with the variable magnification optical system, and a method for manufacturing the variable magnification optical system.