Variable Magnification Optical System Aberration Control
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Solution Overview
Problem
Existing variable magnification optical systems face challenges in reducing variations in aberrations, particularly spherical aberration, at varying magnification levels, which affects imaging performance.
Innovation Solution
The proposed variable magnification optical system consists of a first lens group, a second lens group, a third lens group, and a rear group, where the distances between adjacent lens groups are varied to achieve multiple focused states with different aberration levels. The rear group includes a first focusing lens group and a second focusing lens group that move along different trajectories during focusing, satisfying the conditional expression -6.80 < f1/f2 < -0.05, where f1 and f2 are the focal lengths of the first and second lens groups, respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional variable magnification optical system is used, then the system can achieve variable magnification, but variations in spherical aberration occur at varying magnification levels
Solution Approach 1:
The optical system is divided into multiple lens groups (first lens group with negative refractive power, second lens group with positive refractive power, third lens group with positive refractive power, and rear group) that can move independently. This segmentation allows each group to contribute differently to magnification variation while maintaining aberration control, resolving the contradiction between variable magnification capability and aberration control precision.
Solution Approach 2:
The patent implements dynamic movement of lens groups during magnification variation. The first, second, and third lens groups move along the optical axis in coordinated fashion, with their movement distances and directions optimized to maintain focus and control spherical aberration across different magnification levels. This dynamic adjustment resolves the contradiction by enabling both magnification change and aberration control.
2Device complexity
If the focal length ratio f1/f2 is not controlled within the specified range, then the optical system design becomes simpler, but the aberration variations increase
Solution Approach 1:
The patent establishes a specific parameter constraint: -6.80 < f1/f2 < -0.05, where f1 is the focal length of the first lens group and f2 is the focal length of the second lens group. This parameter control ensures that the negative lens group and positive lens group have appropriately balanced refractive powers, enabling effective spherical aberration control during magnification variation while maintaining reasonable design complexity.
3Manufacturing precision
If multiple lens groups are added to control aberrations, then aberration variations are reduced, but the device complexity increases
Solution Approach 1:
Each lens group in the patent serves multiple functions: the first lens group (negative refractive power) contributes to both magnification variation and spherical aberration control; the second and third lens groups (positive refractive power) similarly participate in both functions. This multi-functionality reduces the need for additional dedicated aberration correction groups, resolving the contradiction between aberration control precision and device complexity.
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 effectively reduces variations in aberrations, including spherical aberration, at varying magnification levels, enhancing the optical performance of the system.
Implementation Method 1
the rear group includes a first focusing lens group and a second focusing lens group disposed closer to an image side than the first focusing lens group, the first and second focusing lens groups moving along different trajectories at focusing
Implementation Method 2
A variable magnification optical system comprises a first lens group, a second lens group, a third lens group, and a rear group in order from an object side; at varying magnification the distances between adjacent lens groups are varied
Data Source
AI summary
A variable magnification optical system comprising a first lens group, a second lens group, a third lens group, and a rear group in order from object side is configured so that at varying magnification the distances between adjacent lens groups are varied; at a predetermined object distance the variable magnification optical system has focused states with different amounts of aberration; the rear group includes a first focusing lens group and a second focusing lens group disposed closer to an image side than the first focusing lens group, the first and second focusing lens groups moving along different trajectories at focusing; at the object distance the first and second focusing lens groups move at transition from a first focused state to a second focused state; and the following conditional expression is satisfied:−6.80<f1/f2<−0.05where f1 and f2 are the focal lengths of the first and second lens groups, respectively.