Zoom Lens System Aberration Compensation via Localized Refractive Power
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Solution Overview
Problem
Existing zoom lens systems face challenges in achieving a high zoom ratio with compactness and maintaining optical performance across the zoom range due to insufficient aberration compensation and increased length from high refractive power lens units, particularly in compensating for spherical and chromatic aberrations.
Innovation Solution
A zoom lens system configuration with specific refractive power and focal length conditions for each lens unit, including a first positive lens unit, a second negative lens unit, a third lens unit with three lens elements, and a fourth lens unit with a pair of positive and negative lens elements, where the second and fourth lens units are moved during zooming, and the third lens unit compensates for spherical and chromatic aberrations throughout the zoom range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the refractive power of each lens unit is increased to reduce the amount of movement and achieve a predetermined zoom ratio, then the overall length of the zoom lens system can be reduced, but the aberration variation during zooming increases and optical performance deteriorates
Solution Approach 1:
The patent applies local quality by assigning different refractive power characteristics to different lens units. Specifically, the third lens unit has higher refractive power for compensating spherical aberration, while the fourth lens unit has higher refractive power for compensating chromatic aberration. This localized optimization allows each lens unit to contribute its specific function without uniformly increasing the refractive power of all units, thereby maintaining optical performance while reducing overall length.
Solution Approach 2:
The patent changes the refractive power parameters of specific lens units to achieve the desired balance. By setting the third lens unit with higher refractive power and the fourth lens unit with higher refractive power, the system optimizes aberration compensation while controlling the overall length. This parameter optimization resolves the contradiction between compactness and optical performance.
2Device complexity
If a single positive lens element is used in the fourth lens unit to simplify the structure, then the device complexity is reduced, but the compensation for chromatic aberration becomes insufficient
Solution Approach 1:
The patent applies local quality by giving the fourth lens unit specific refractive power characteristics tailored for chromatic aberration compensation. By optimizing the refractive power of the fourth lens unit (which may include multiple elements with different glass types), the system achieves effective chromatic aberration correction without unnecessarily increasing overall device complexity.
Solution Approach 2:
The patent employs composite materials by using multiple lens elements with different glass types and refractive powers in the fourth lens unit. This composite approach enables effective chromatic aberration compensation while maintaining reasonable structural complexity.
3Reliability
If three positive lens elements are included in the third lens unit and one or two positive lens elements in the fourth lens unit, then the aberration compensation is improved, but the overall length of the zoom lens system increases
Solution Approach 1:
The patent applies local quality by concentrating higher refractive power in specific lens units. The third lens unit has higher refractive power for spherical aberration compensation, while the fourth lens unit has higher refractive power for chromatic aberration compensation. This localized optimization reduces the need for multiple lens elements throughout the system, thereby controlling overall length while maintaining effective aberration compensation.
Solution Approach 2:
The patent optimizes the refractive power parameters of the third and fourth lens units to achieve the desired balance between aberration compensation and compactness. By carefully selecting and optimizing these parameters, the system achieves effective aberration correction without excessively increasing the overall length.
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 allows for a compact zoom lens system with a high zoom ratio and improved optical performance across the zoom range by effectively compensating for aberrations and reducing the overall length of the lens system.
Implementation Method 1
a first lens unit of positive refractive power, a second lens unit of negative refractive power, a third lens unit of positive refractive power, and a fourth lens unit of positive refractive power
Data Source
AI summary
At least one exemplary embodiment is directed to a zoom lens system which includes, in order from an object side to an image side, a first lens unit of positive optical power, a second lens unit of negative optical power, a third lens unit of positive optical power, and a fourth lens unit of positive optical power. At least the second and fourth lens units are moved for zooming. The third lens unit includes, in order from the object side to the image side, three lens elements, a positive lens element, a negative lens element, and a positive lens element. The fourth lens unit includes, in order from the object side to the image side, two lens elements, a positive lens element and a negative lens element. The above-described configuration of the zoom lens system allows appropriate setting of the imaging magnification of the fourth lens unit and the focal lengths of the third and fourth lens units.