Five-Group Variable Magnification Optics for Aberration Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional variable magnification optical systems suffer from significant aberration variations, particularly in spherical aberration, coma aberration, and curvature of field, which affect the optical performance and lens barrel size.
Innovation Solution
A variable magnification optical system comprising five lens groups with specific refractive powers and focal lengths, where the first lens group is fixed relative to the image plane, and neighboring lens groups are varied in distance during magnification changes, with the fourth lens group moved for focusing, while satisfying conditional expressions to optimize aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional variable magnification optical system design is used, then the system can achieve variable magnification, but aberration variations become large
Solution Approach 1:
The optical system is divided into five distinct lens groups with specific positive and negative refractive powers. This segmentation allows independent optimization of each group's contribution to aberration control while maintaining overall variable magnification capability. The alternating positive-negative-positive-positive-negative configuration enables precise manipulation of ray paths to suppress aberration variations across different magnification settings.
Solution Approach 2:
The patent employs specific conditional expressions that define optimal parameter ranges for focal lengths (f1 through f5) and inter-group distances. By constraining these parameters within calculated ranges, the system maintains consistent aberration performance across the variable magnification range. The conditional expressions ensure that parameter changes during magnification adjustment remain within bounds that prevent excessive aberration variations.
2Manufacturing precision
If more lens groups are added to correct aberrations, then aberration correction improves, but device complexity increases
Solution Approach 1:
Multiple aberration correction functions are merged into a coordinated five-group configuration. Rather than adding independent correction elements, the patent integrates correction capabilities into the primary lens groups themselves through the alternating positive-negative refractive power arrangement. This merging approach achieves comprehensive aberration control while maintaining a compact, unified structure.
Solution Approach 2:
Each lens group serves multiple functions simultaneously. For example, the negative refractive power groups not only diverge light but also correct spherical and coma aberrations, while positive groups provide convergence and field curvature control. This multi-functionality reduces the need for dedicated correction elements, thereby limiting overall system complexity.
3Ease of operation
If lens groups are moved for focusing, then focusing capability is achieved, but sensitivity to camera shake increases
Solution Approach 1:
The fourth lens group acts as an intermediary focusing element that can be moved independently to achieve focus adjustment. By positioning this group strategically within the optical path and using it as the primary focusing actuator, the system achieves effective focusing while minimizing the impact of movement on overall system stability and camera shake sensitivity.
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, achieves compact size, and maintains high optical performance across varying magnifications, with simplified lens barrel mechanisms and reduced sensitivity to camera shake.
Implementation Method 1
a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having positive refractive power; and a fifth lens group having negative refractive power
Data Source
AI summary
Comprising, in order from an object side: a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having positive refractive power, and a fifth lens group having negative refractive power; upon varying a magnification, the first lens group being fixed with respect to the image plane, and each distance between the neighboring lens groups being varied; upon focusing, at least a portion of the fourth lens group being moved; and predetermined conditional expression(s) being satisfied, thereby variations in various aberrations upon varying magnification being superbly suppressed.