Imaging Lens Layout for Compact Focus and Aberration Control
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Solution Overview
Problem
Existing imaging lenses are not compact and lightweight while maintaining favorable optical performance, and there is a need for improved designs that address this issue.
Innovation Solution
An imaging lens configuration with a stationary first lens group and a focus lens group that moves during focusing, adhering to specific conditional expressions for optical parameters, including curvature radii, refractive indices, and focal lengths, to achieve compactness and optical efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional imaging lens designs are used, then optical performance can be maintained, but the lens size and weight increase
Solution Approach 1:
The imaging lens is divided into multiple lens groups (first lens group G1, second lens group G2, third lens group G3, fourth lens group G4) with different functions. The first lens group handles wide-angle imaging, the second handles telephoto imaging, the third is the focus lens group, and the fourth corrects aberrations. This segmentation allows each group to be optimized for specific functions, reducing overall size and weight while maintaining optical performance.
Solution Approach 2:
The lens groups are arranged in a nested configuration along the optical axis, with the focus lens group (G3) positioned between the wide-angle group (G1-G2) and the aberration correction group (G4). This nested arrangement allows compact packaging of multiple functional groups, reducing the overall lens length and weight while maintaining the necessary optical path.
2Reliability
If more lens elements are added to improve optical performance, then aberration correction improves, but device complexity increases
Solution Approach 1:
Each lens group serves multiple functions. For example, the first lens group (G1) not only provides wide-angle imaging but also contributes to aberration correction. The fourth lens group (G4) corrects both spherical and chromatic aberrations while maintaining focus. This multi-functionality reduces the need for additional dedicated correction elements, simplifying the overall structure.
Solution Approach 2:
Different lens groups have different refractive indices and curvature radii optimized for their specific locations and functions. The negative lens in the fourth group has specific curvature radii (Rf and Rr) and Abbe number (vn) tailored for correcting spherical and chromatic aberrations at the image side, while the positive lens in the third group has parameters optimized for focus control. This localized optimization achieves effective aberration correction without requiring uniform complexity throughout the system.
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 proposed lens design achieves a compact and lightweight imaging lens with improved optical performance, reducing size and weight while maintaining high resolution and correcting aberrations.
Implementation Method 1
an imaging lens includes, successively in order from a position closest to an object side to an image side: a first lens group that remains stationary with respect to an image plane during focusing; and a focus lens group that moves along an optical axis during focusing
Data Source
AI summary
The imaging lens includes, successively in order from a position closest to an object side: a first lens group that remains stationary with respect to an image plane during focusing; and a focus lens group that moves along an optical axis during focusing. Assuming that a maximum image height is Ymax, and a focal length of the imaging lens is f, and a sum of a back focal length in terms of an air-equivalent distance and a distance on the optical axis from a lens surface closest to the object side to a lens surface closest to the image side is TL, the imaging lens satisfies Conditional Expressions (1) and (2).0.1<Ymax/f<0.26 (1):0.4<TL/f<1.1 (2):