Zoom Lens Aberration Control via Dynamic Lens Spacing
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Solution Overview
Problem
Zoom lenses with a wide angle of view and high zoom ratio face challenges in achieving high optical performance and size reduction while effectively correcting aberrations, particularly in the focal length range from the zoom middle position to the telephoto end, where aberrations increase, leading to image degradation in the periphery.
Innovation Solution
The zoom lens design includes a specific configuration where the movement loci of the second and third lens units are defined to widen the distance between them from the wide angle end to the zoom middle range and maintain a predetermined distance to the telephoto end, with an aperture stop placement and a rear lens group that includes convex and concave lenses, ensuring the lens units do not move for zooming, thereby correcting curvature of field and axial chromatic aberrations across the entire zoom range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the distance between the second and third lens units is always widened for zooming from the wide angle end to the telephoto end, then the zoom ratio is increased, but the aberrations increase particularly for the focal length range from the zoom middle position to the telephoto end
Solution Approach 1:
The patent applies dynamic control of lens unit distances by defining specific movement loci for the second and third lens units. The distance between these units is not uniformly increased but is dynamically adjusted according to the zoom position: widened from wide angle to middle position to achieve high zoom ratio, then maintained at a predetermined distance from middle to telephoto position to correct aberrations. This dynamic adjustment resolves the contradiction between achieving high zoom ratio and controlling aberrations across different focal length ranges.
2Adaptability or versatility
If a wider angle of view and a higher zoom ratio are accomplished at the same time, then the lens coverage is improved, but the size increases
Solution Approach 1:
The patent changes the operational parameters of the lens system by optimizing the movement loci of the second and third lens units. By precisely controlling how these units move during zooming - widening distance at certain ranges and maintaining predetermined distance at others - the system achieves wide angle of view and high zoom ratio without requiring excessive lens size. This parameter optimization allows compact design while maintaining high adaptability.
3Adaptability or versatility
If the lens units are configured to move for zooming, then the zoom ratio is increased, but the weight increases
Solution Approach 1:
The patent implements dynamic zooming control where only specific lens units (second and third units with negative refractive power) are configured to move, while other units remain stationary. The movement is dynamically controlled with specific loci: the distance between the second and third units is widened from wide angle to middle position, then maintained at a predetermined distance from middle to telephoto position. This selective and controlled movement achieves high zoom ratio while minimizing the weight of moving components compared to systems where all lens units must move.
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 and size reduction while effectively correcting aberrations, ensuring uniform resolution from the center to the periphery of the image, even at the telephoto end, thereby enhancing the zoom lens's overall performance and reducing size and weight.
Implementation Method 1
a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a negative refractive power
Data Source
Figure 1~2A
Figure 2B~2D
Figure 3~4A
AI summary
A zoom lens includes in order from an object side: a positive first lens unit not moving for zooming; a negative second lens unit moving for zooming; a negative third lens unit moving for zooming; an intermediate lens group including a lens unit and moving for zooming; and a rear lens group including a lens unit, a lens unit, closest to an object of the zoom lens, not moving for zooming, an aperture stop being placed on a side of the object to or in the rear lens group, a distances between each pair of adjacent lens units changes for zooming, and a distance between the second and third lens units at a wide angle end, a distance between the second and third lens units at a telephoto end, and a maximum distance between the second and third lens units in a certain zoom range are appropriately set.