Zoom Lens Aberration Correction via Segmented Rear Group
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Solution Overview
Problem
Existing zoom lenses face challenges in achieving high magnification while maintaining shortening the shortest imaging distance and optical performance, as they struggle with aberration correction and lens group movement at increased magnification.
Innovation Solution
A zoom lens configuration with a first lens group having positive refractive power, a second lens group with negative refractive power, and a rear group including at least a third, fourth, and fifth lens group, where any one of these groups acts as a focus group, allowing for variable magnification by adjusting the distance between adjacent lens groups, and satisfying specific expressions to optimize focal lengths and lateral magnifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the magnification of the zoom lens is increased, then the zoom capability is improved, but the shortest imaging distance cannot be shortened and optical performance deteriorates
Solution Approach 1:
The zoom lens is divided into five distinct lens groups (G1-G5) with different refractive powers, where each group has a specific function in the zoom mechanism. The rear group (G3-G5) is further segmented to provide sufficient movement region for focus adjustment while maintaining high magnification capability.
Solution Approach 2:
The second lens group (G2) with negative refractive power is positioned to have a specific movement range that provides variable magnification ratio, while the rear group components have different movement characteristics optimized for their local functions in maintaining optical performance at high magnification.
2Adaptability or versatility
If the magnification of the zoom lens is increased, then the zoom capability is improved, but the shortest imaging distance cannot be shortened
Solution Approach 1:
The zoom lens employs dynamic movement of multiple lens groups during focusing operation. The focus group within the rear group moves along the optical axis with a sufficiently large movement region, allowing the focal plane to be adjusted dynamically to achieve short imaging distance while maintaining high magnification.
Solution Approach 2:
The lens groups are arranged in a nested configuration where the rear group (G3-G5) contains components that can move independently within the overall zoom structure, allowing compact packaging while maintaining sufficient focus adjustment range for short imaging distance.
3Device complexity
If a variable magnification ratio using the second lens group is small, then the zoom structure is simplified, but the amount of movement of the second lens group becomes large and the moving region of the focus group becomes small
Solution Approach 1:
The zoom lens separates the magnification function into two parts: the second lens group (G2) provides a baseline variable magnification ratio, while the rear group (G3-G5) provides additional magnification capability. This segmentation allows G2 to have a moderate movement range while the rear group compensates to achieve high overall magnification without sacrificing focus group movement region.
4Adaptability or versatility
If the third lens group, fourth lens group, or fifth lens group is moved to achieve high magnification, then the zoom capability is improved, but the moving region of the focus group becomes small and optical performance deteriorates
Solution Approach 1:
The zoom lens employs dynamic coordination of multiple lens groups during zoom operation. When achieving high magnification, the system dynamically adjusts the positions of G3, G4, and G5 while maintaining sufficient movement region for the focus group through coordinated movement patterns, thereby preserving aberration correction capability.
Solution Approach 2:
The patent optimizes the refractive powers and movement ranges of the lens groups by adjusting design parameters. The rear group components are designed with specific refractive power ratios and movement characteristics that enable high magnification while maintaining sufficient focus adjustment range for effective aberration correction.
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 enables high-magnification zoom lenses that can shorten the shortest imaging distance and maintain high optical performance by effectively correcting aberrations and optimizing lens group movements.
Implementation Method 1
a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a rear group having a positive refractive power as a whole in order from an object side
Data Source
AI summary
A zoom lens includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a rear group having a positive refractive power as a whole in order from an object side. The zoom lens has specific optical characteristics indicated by two expressions.