Three-Lens Imaging System Aberration Correction
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Solution Overview
Problem
Conventional imaging lenses for small cameras face challenges in achieving both miniaturization and effective aberration correction, particularly due to limitations in focal length and refractive power distribution, which affect image quality and lead to issues like astigmatism and chromatic aberration.
Innovation Solution
The imaging lens configuration consists of a first lens with positive refractive power, a second lens with negative refractive power, and a third lens with positive refractive power, arranged in a specific order, with specific curvature radius ratios and focal length relationships to optimize miniaturization and aberration correction, including constraints like 4.0<f12/f<10.0, 1.0<T1/T2<2.0, 2.0<R2r/R3f<35.0, and 0.6<R2r/f<10.0, ensuring effective astigmatism and chromatic aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the whole lens system has a long focal length to correct aberrations, then aberration correction is improved, but the length of the imaging lens on the optical axis increases, limiting miniaturization
Solution Approach 1:
The patent applies parameter changes by precisely controlling the focal length ratio (f1/f) between the first lens and the whole lens system within 0.2-0.5, and the composite focal length ratio (f12/f) between the first and second lenses and the whole lens system within 4.0-10.0. These parameter optimizations enable shorter overall focal length while maintaining aberration correction capability, thus resolving the contradiction between miniaturization and aberration correction.
2Length of moving object
If the first lens has relatively weak positive refractive power to satisfy focal length requirements, then the overall focal length is controlled, but it becomes difficult to attain miniaturization and correct chromatic aberrations
Solution Approach 1:
The patent segments the refractive power distribution across three lenses rather than relying on a single lens. The first lens has positive refractive power with f1/f = 0.2-0.5, the second lens has negative refractive power, and the third lens has positive refractive power. This segmentation allows the first lens to have moderate power while the combined system achieves the required focal length and miniaturization goals.
Solution Approach 2:
The patent optimizes multiple parameters simultaneously: the focal length ratio f1/f = 0.2-0.5, the composite focal length ratio f12/f = 4.0-10.0, and the spacing ratios T1/T2 = 1.0-2.0. These parameter changes enable the first lens to have appropriate refractive power that contributes to both miniaturization and chromatic aberration correction without making the overall system too long.
3Length of moving object
If the imaging lens is miniaturized with shorter focal length, then the size is reduced, but aberration correction becomes insufficient
Solution Approach 1:
The patent achieves miniaturization while maintaining aberration correction by optimizing key parameters: the focal length ratio f1/f = 0.2-0.5 ensures the first lens contributes appropriately to the overall focal length; the composite focal length ratio f12/f = 4.0-10.0 controls the combined effect of the first two lenses; and the spacing ratio T1/T2 = 1.0-2.0 optimizes the distances between lenses. These parameter optimizations enable shorter overall focal length while maintaining sufficient aberration correction capability.
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 allows for the attainment of both miniaturization and satisfactory aberration correction, ensuring improved image-forming performance by restraining astigmatism and chromatic aberrations within acceptable ranges, while maintaining a small-sized lens system.
Implementation Method 1
a first lens (L1) having positive refractive power; a second lens (L2) having negative refractive power; and a third lens (L3) having positive refractive power, arranged in this order from an object side to an image plane side
Data Source
AI summary
An imaging lens includes a first lens having positive refractive power; a second lens having negative refractive power; and a third lens having positive refractive power, arranged in this order from an object side to an image plane side. Further, the first lens is formed in a shape so that a curvature radius of a surface thereof on the object side is positive. The second lens is formed in a shape so that a curvature radius of a surface thereof on the object side is negative and a curvature radius of a surface thereof on the image plane side is positive. The third lens is formed in a shape so that a curvature radius of a surface thereof on the object side and a curvature radius of a surface thereof on the image plane side are both positive.