Zoom Lens Aberration Control via Segmented Unit Movement
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Solution Overview
Problem
Existing zoom lenses face challenges in achieving a high zoom ratio with high optical performance over the entire zoom range and object length while maintaining a small size and wide angle of view, due to increased variation of aberrations associated with zooming and focusing.
Innovation Solution
A zoom lens configuration with specific refracting powers and movements of lens units, including a first lens unit with positive refracting power, a second lens unit with negative refracting power, and subsequent units, where the distances between these units change during zooming and focusing to achieve a high zoom ratio and wide angle of view, while satisfying conditional expressions for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the refracting powers of lens units are increased to achieve a high zoom ratio and small size, then the zoom ratio and compactness are improved, but the variation of aberrations increases making it difficult to achieve high optical performance
Solution Approach 1:
The zoom lens is divided into six lens units with alternating positive and negative refracting powers. This segmentation allows each lens unit to contribute differently to the overall optical function, enabling high zoom ratio while controlling aberration variation through coordinated movement of individual units rather than relying on excessive refracting power in single elements.
Solution Approach 2:
The patent employs conditional expressions that define specific relationships between focal lengths, distances, and refracting powers of different lens units. By changing and optimizing these parameters within defined ranges, the system achieves high zoom ratio while maintaining stable optical performance across the zoom range.
2Volume of moving object
If the number of lenses is reduced to make the optical system smaller, then the system size is decreased, but the ability to correct aberrations over the entire zoom range and object length deteriorates
Solution Approach 1:
The optical system is segmented into six functional lens units with alternating signs of refracting power. This configuration allows compact arrangement while maintaining sufficient degrees of freedom for aberration correction through coordinated movement of the lens units during zooming and focusing operations.
Solution Approach 2:
The patent implements dynamic movement of lens units during zooming and focusing operations. The distances between lens units change according to specific relationships defined by conditional expressions, allowing the system to adapt its optical configuration to maintain high performance across different object lengths and zoom positions despite having a reduced number of lenses.
3Manufacturing precision
If a positive-lead type zoom lens is designed to achieve high optical performance, then the optical performance is improved, but the complexity of lens configuration and power distribution increases
Solution Approach 1:
The patent establishes specific conditional expressions that define the relationships between focal lengths and distances of lens units. These parameter constraints guide the design process, allowing systematic determination of lens configurations that achieve high optical performance without requiring overly complex arrangements.
Solution Approach 2:
The positive-lead zoom lens is segmented into six units with alternating positive and negative refracting powers. This segmentation creates a regular pattern that simplifies the overall configuration while enabling sophisticated aberration control through the coordinated action of individual units.
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 enables a small zoom lens with a high zoom ratio, sufficient back focus, and satisfactory optical performance over the entire zoom range and object length, reducing aberrations and system size.
Implementation Method 1
a first lens unit having positive refracting power; a second lens unit having negative refracting power; a third lens unit having positive refracting power; a fourth lens unit having negative refracting power; a fifth lens unit having positive refracting power; and a sixth lens unit having negative refracting power
Data Source
AI summary
A zoom lens includes, from the object side to the image side, first to sixth lens units having positive, negative, positive, negative, positive, negative refracting powers. In zooming from the wide angle end to the telephoto end, the lens units are moved such that the distance between the first and second lens units increases, the distance between the second and third lens units decreases, the distance between the third and fourth lens units increases, and the distance between the fourth and fifth lens units decreases. In focusing from an infinitely distant object to a near object, the sixth lens unit is moved toward the image side. The distance between the rear principal point of the second lens unit and the front principal point of the rear lens group at the wide angle end, and the focal length of the rear lens group at the wide angle end are appropriately set.