Zoom Lens Aberration Control via Segmented Unit Design
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Solution Overview
Problem
Existing zoom lenses face challenges in achieving high optical performance while maintaining a small size and reduced weight, as increased refractive power leads to fluctuation in aberrations during zooming, making it difficult to correct various optical errors with a small number of lenses.
Innovation Solution
The zoom lens configuration includes a specific arrangement of lens units with varying refractive powers and focal lengths, such as a first positive lens unit, a second negative lens unit, and a third positive lens unit, with carefully controlled distances and curvature radii to minimize aberrations and weight, adhering to specific conditional expressions to optimize performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the refractive power of each lens unit is increased to reduce the size of the zoom lens, then the lens size is reduced, but the fluctuation in various aberrations increases making it difficult to correct optical errors
Solution Approach 1:
The zoom lens is divided into multiple lens units (first through fifth lens units) with alternating positive and negative refractive powers. Each lens unit is independently designed with specific refractive power ranges, allowing the system to achieve compact size through strategic placement of high-power elements while distributing aberration correction across multiple segments rather than concentrating it in a single element.
Solution Approach 2:
Different lens units are assigned specific functional roles based on their local optical properties. The first lens unit handles wide-angle to telephoto transitions, the second and fifth units with negative refractive powers correct for spherical and chromatic aberrations, while the third and fourth units contribute to focal length variation. This localized functional assignment allows each element to optimize for its specific role while maintaining overall system compactness.
2Device complexity
If a small number of lenses is used to reduce weight and simplify structure, then the lens structure is simplified, but it becomes difficult to correct various aberrations effectively
Solution Approach 1:
Rather than using fewer large elements, the patent segments the optical system into five distinct lens units with alternating signs of refractive power. This segmentation allows each unit to be relatively simple in structure while collectively providing comprehensive aberration correction through their combined optical actions.
Solution Approach 2:
Multiple lens units with different refractive powers are merged into a single integrated zoom lens system. The positive and negative lens units work in combination, with their complementary optical effects reinforcing each other to correct various aberrations (spherical, chromatic, coma) that would be difficult to correct with a smaller number of elements.
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 achieves high optical performance across the entire zoom range while maintaining a compact size and reduced weight, effectively managing aberrations and magnification variations, thereby enhancing the zoom lens's overall performance and usability in digital cameras and other image pickup apparatuses.
Implementation Method 1
a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, a third lens unit L3 having a positive refractive power, and a fourth lens unit L4 having a positive refractive power
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A zoom lens including, in order from object side to image side, first to fourth lens units respectively having positive, negative, positive, and positive refractive powers. During zooming from a wide-angle end to a telephoto end, the first lens unit is arranged to move, the distance between the first lens unit and the second lens unit increases, the distance between the second lens unit and the third lens unit decreases, and the distance between the third lens unit and the fourth lens unit decreases. The second lens unit consists of a first lens having a negative refractive power and a second lens having a positive refractive power, the second lens being disposed on the image side of the first lens. A predetermined condition is satisfied.