Imaging Lens with Integral Moving Groups for Compact High-Resolution Optics
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Solution Overview
Problem
Existing imaging lenses for digital cameras face challenges in achieving a small F number, high resolution, and compact size while effectively correcting field curvature and astigmatism, with previous designs having insufficient F number and longer total lens lengths.
Innovation Solution
The proposed imaging lens configuration includes a first lens group with a positive refractive power, a stop, a second lens group with a positive refractive power, and a third lens group with a negative refractive power, where the first and second lens groups move integrally during focusing, and the third lens group remains stationary, utilizing cemented lenses and aspheric lenses to optimize refractive power and curvature, adhering to specific conditional expressions to suppress aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a lens system with focal length equivalent to 35mm or 28mm is used, then the field of view is improved, but field curvature and astigmatism correction is insufficient
Solution Approach 1:
The lens system is divided into multiple lens groups (first lens group with positive refractive power, second lens group with positive refractive power, third lens group with negative refractive power) that can move independently during focusing. This segmentation allows each group to be optimized for specific functions, improving both field of view and aberration correction simultaneously
Solution Approach 2:
The patent employs aspheric surfaces in the lens design to correct field curvature and astigmatism. The aspheric shapes allow for better control of light rays across the entire field of view, resolving the contradiction between wide field of view and aberration correction
2Illumination intensity
If the F number is reduced to achieve small aperture, then light gathering ability is improved, but lens length increases
Solution Approach 1:
The patent uses parameter changes in the lens design, specifically optimizing the refractive powers and distances between lens groups. By carefully controlling the ratio of focal lengths and spacing, the system achieves small F number (high light gathering ability) while keeping the total lens length compact through the telephoto configuration
3Manufacturing precision
If more lenses are added to improve resolution, then optical performance is improved, but device complexity and size increase
Solution Approach 1:
The patent merges multiple lens elements into cemented lens groups, where lenses are optically bonded together. This reduces the number of separate components and air-glass interfaces, simplifying the overall system while maintaining high resolution through the combined optical power of the cemented groups
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 enables an imaging lens with a small F number, high resolution, and compact size, effectively correcting various aberrations and reducing the lens system's length, thereby enhancing optical performance and portability.
Implementation Method 1
a lens surface closest to the object side in the first lens group is convex
Implementation Method 2
The first lens group includes a cemented lens in which a negative lens and a positive lens are cemented
Implementation Method 3
an aspheric lens having a negative refractive power
Data Source
AI summary
The imaging lens consists of, in order from the object side, a first positive lens group, a stop, a second positive lens group, and a third negative lens group. During focusing, the first lens group and the second lens group move integrally. The first lens group consists of three or less lenses. The first lens group includes a cemented lens in which a negative lens and a positive lens are cemented in order from the object side. The third lens group consists of, in order from the object side, a negative aspheric lens, a negative lens, and a positive lens. The lens closest to the image side in the second lens group is a biconvex lens, and the imaging lens satisfies a predetermined conditional expression regarding the radius of curvature of the surface of the biconvex lens.