Zoom Lens Aberration Control via Sub-Unit Segmentation
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Solution Overview
Problem
Conventional zoom lenses with large aperture ratios and high zoom ratios face challenges in maintaining small size, weight, and high optical performance while minimizing aberration variations and breathing issues, especially at the wide angle end.
Innovation Solution
A zoom lens configuration with a first lens unit having positive refractive power that does not move for zooming, a second lens unit with negative refractive power that moves during zooming, and at least one zoom lens unit that moves, where the first lens unit includes sub-lens units with specific refractive powers and movement ratios to suppress aberration variations and breathing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of lenses is increased to suppress aberration variations and breathing, then optical performance is improved, but the size of the entire lens system increases
Solution Approach 1:
The first lens unit is divided into three sub lens units (U11, U12, U13) with different refractive powers. During focus adjustment, only the second and third sub lens units move while the first sub lens unit remains stationary. This segmentation allows for aberration correction through selective movement of specific sub units, achieving high optical performance without requiring an excessive total number of lenses in the system.
2Reliability
If a zoom lens has a large aperture ratio and high zoom ratio, then imaging performance is improved, but aberration variations increase
Solution Approach 1:
The patent implements a dynamic focus adjustment mechanism where the second and third sub lens units of the first lens unit move during focus adjustment, while the first sub lens unit remains stationary. This dynamic configuration allows the lens system to adapt its optical path and correct aberrations at different focus distances, maintaining stable aberration characteristics across the entire focus range despite the large aperture ratio and high zoom ratio.
3Reliability
If the first lens unit has multiple lenses to correct aberrations at telephoto end, then optical performance is improved, but the size of the entire lens system increases
Solution Approach 1:
The first lens unit is segmented into three sub lens units with the first sub lens unit (U11) having negative refractive power and remaining stationary during focus adjustment. This stationary negative power sub unit helps control aberrations at the telephoto end without requiring additional moving lenses, thereby maintaining compact size while achieving high optical performance.
Solution Approach 2:
Different sub lens units are assigned different refractive powers and movement characteristics tailored to their specific functions. The first sub lens unit with negative power remains stationary to control telephoto aberrations, while the second and third sub units with positive power move to correct focus-related aberrations. This localized optimization of each sub unit's properties achieves comprehensive aberration correction without increasing overall system size.
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 solution achieves a zoom lens with a large aperture ratio, high zoom ratio, small size, and high optical performance, with reduced aberration variations and breathing, particularly at the wide angle end, by optimizing the refractive powers and movements of the sub-lens units.
Implementation Method 1
a first lens unit having a positive refractive power which does not move for zooming
Implementation Method 2
a second lens unit having a negative refractive power which moves during zooming
Data Source
AI summary
A zoom lens in which aberration variations at telephoto end during focusing are suppressed while suppressing breathing at wide angle end, which includes, from object side: a positive first unit which does not move for zooming; a negative second unit which moves during zooming; at least one zooming unit which moves during zooming; a stop; and an imaging unit which does not move for zooming. The first unit includes: a negative first sub unit which does not move for focusing; a positive second sub unit which moves to image side during focusing from infinity to proximity; and a positive third sub unit which moves to object side during focusing from infinity to proximity. Focal lengths of the first, second, first sub, and second sub units, and amounts of movement of the second and third sub units during the focusing from infinity proximity are appropriately set.