Imaging Lens Aberration Correction via Segmented Groups
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Solution Overview
Problem
Existing imaging lenses for digital and cinematic cameras have large F numbers and insufficient correction of aberrations such as astigmatism, field curvature, and longitudinal chromatic aberration, failing to meet the demands of improved resolution and brightness.
Innovation Solution
An imaging lens configuration comprising a first lens group with positive refractive power, a stop, and a second lens group with positive refractive power, along with a fixed third lens group having negative refractive power, which includes specific lens combinations and surface curvatures to correct aberrations and achieve a small F number, allowing for integral movement during focusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If existing imaging lens configurations are used, then the structure is relatively simple, but the F number is large and aberration correction is insufficient
Solution Approach 1:
The imaging lens is divided into multiple lens groups (first lens group with positive refractive power, second lens group with negative refractive power, and third lens group with positive refractive power) arranged in sequence from the object side. Each lens group contains specific lens elements with defined refractive powers and curvature characteristics, enabling independent optimization of aberration correction in each group while achieving overall small F number performance
Solution Approach 2:
Specific lens elements are designed with localized optical properties: the first lens group includes a negative meniscus lens with convex surface toward the object side to correct spherical aberration, the second lens group contains a negative meniscus lens with concave surface toward the image side to control field curvature, and the third lens group includes positive meniscus lenses to correct astigmatism. Each element's curvature and refractive power are optimized for its specific aberration correction function
2Measurement precision
If existing imaging lens configurations are used, then the lens structure is simpler, but resolution performance is insufficient
Solution Approach 1:
The lens system is segmented into three functional lens groups with specific aberration correction responsibilities. The first lens group primarily corrects spherical aberration, the second lens group controls field curvature and astigmatism, and the third lens group corrects remaining chromatic and monochromatic aberrations. This segmentation allows each group to be optimized for specific resolution-critical aberrations
Solution Approach 2:
The patent specifies precise parameter ranges for each lens element including refractive powers (f1, f2, f3), curvature radii (R1, R2, R3, R4, R5, R6), and axial distances (d1, d2, d3, d4, d5). These parameters are optimized to achieve small F number (F < 2.0) while correcting aberrations to enable high-resolution imaging. The conditional expressions (1) through (6) define the parameter relationships necessary for optimal resolution performance
3Manufacturing precision
If existing imaging lens configurations are used, then the lens design is simpler, but various aberrations are not favorably corrected
Solution Approach 1:
Each lens element is designed with specific local optical properties: positive meniscus lenses with convex surfaces toward the object side in the first and third groups for spherical aberration correction, negative meniscus lenses with specific curvature directions in the second group for field curvature control, and biconvex/biconcave lenses for chromatic aberration correction. The curvature radii and refractive powers are locally optimized for each element's aberration correction function
Solution Approach 2:
The patent defines specific parameter relationships through conditional expressions: the ratio of focal lengths (0.3 < f2/f1 < 1.5), the curvature radii relationships (R2/R1, R4/R3, R6/R5), and axial distance ratios (d2/d1, d4/d3, d5/d4). These parameter constraints ensure optimal aberration correction while maintaining a manageable lens configuration
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 configuration results in a bright optical system with effective correction of spherical aberration and longitudinal chromatic aberration, preventing increases in spherical aberration, astigmatism, and field curvature, enabling high-resolution image capture.
Implementation Method 1
a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power provided in this order from the object side
Data Source
AI summary
An imaging lens includes: a first lens group; a stop; a positive second lens group; and a negative third lens group which is fixed while focusing, in order from the object side. The first lens group includes at least one positive lens, at least one cemented lens, and a negative meniscus lens having a concave surface toward the image side, in order from the object side. The second lens group includes a cemented lens formed by a biconcave lens and a biconvex lens and a biconvex lens, in order from the object side. The third lens group includes a negative meniscus lens having a convex surface toward the object side, a biconcave lens, and a biconvex lens, in order from the object side. The first lens group, the stop, and the second lens group move integrally along the optical axis to focus from an infinite to a finite distance.