Seven-Lens Imaging System with Aberration Correction
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Solution Overview
Problem
Conventional imaging lenses for small cameras, such as those in cellular phones and smartphones, face challenges in achieving both downsizing and satisfactory correction of aberrations, particularly chromatic aberration, while maintaining high-resolution image formation.
Innovation Solution
The imaging lens configuration includes a first lens group with positive refractive power, a second lens group with positive refractive power, and a third lens group with negative refractive power, arranged from the object side to the image plane side, with specific Abbe's number and focal length ratios to distribute refractive power effectively, allowing for balanced correction of aberrations and downsizing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of lenses is increased to achieve high resolution, then image quality is improved, but the size of the imaging lens increases
Solution Approach 1:
The imaging lens is divided into multiple lens groups (first lens group with positive refractive power, second lens group with positive refractive power, and third lens group with negative refractive power) arranged in sequence from the object side. Each lens group contains specific numbers of lenses (3, 2, and 2 lenses respectively) with controlled refractive powers, allowing the system to achieve high resolution through distributed optical correction while managing overall size through modular grouping.
Solution Approach 2:
The patent applies specific parameter constraints to control aberrations and size: the ratio of focal lengths of the first and second lens groups is controlled within 0.3 to 1.5, the ratio of focal length of the third lens group to the whole lens system is between -0.3 and -0.05, and Abbe's numbers of individual lenses are constrained (νd1>20, νd2>20, νd3<50, νd4>20, νd5<50). These parameter optimizations enable effective aberration correction with a compact seven-lens configuration.
2Volume of moving object
If the number of lenses is reduced to downsize the imaging lens, then the size is decreased, but aberration correction becomes insufficient
Solution Approach 1:
The patent optimizes specific optical parameters to achieve effective aberration correction with only seven lenses. The refractive power distribution is precisely controlled through focal length ratios (first/second lens group: 0.3-1.5, third lens group/whole system: -0.3 to -0.05), and material properties are constrained via Abbe's number ranges. This parameter optimization enables compact design without sacrificing correction quality.
Solution Approach 2:
Different lens groups are assigned specific functions through localized optical properties: the first lens group (positive refractive power) handles initial light convergence, the second lens group (positive refractive power) provides intermediate correction, and the third lens group (negative refractive power) addresses residual aberrations. Each lens within groups also has specific Abbe's number constraints to target particular aberration types locally, achieving comprehensive correction with minimal lens count.
3Measurement precision
If chromatic aberration is corrected using conventional methods, then color accuracy is improved, but the lens configuration becomes complex
Solution Approach 1:
Chromatic aberration is corrected through optimized selection of lens materials with specific Abbe's numbers rather than adding more lenses. The patent constrains Abbe's numbers to specific ranges (νd1>20, νd2>20, νd3<50, νd4>20, νd5<50) to control dispersion characteristics. This material parameter optimization achieves effective chromatic aberration correction within the seven-lens configuration without increasing structural complexity.
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 the production of a small-sized imaging lens with improved aberration correction, including chromatic aberration, while maintaining high-resolution image formation, suitable for use in small cameras like cellular phones and smartphones.
Implementation Method 1
an imaging lens includes a first lens group having positive refractive power; a second lens group having positive refractive power; and a third lens group having negative refractive power, arranged in the order from an object side to an image plane side
Data Source
AI summary
An imaging lens includes a first lens group having positive refractive power; a second lens group; and a third lens group having negative refractive power, arranged in this order from an object side to an image plane side. The first lens group includes a first lens, a second lens, and a third lens. The second lens group includes a fourth lens and a fifth lens. The third lens group includes a sixth lens and a seventh lens having negative refractive power. The first lens is formed in a meniscus shape at a paraxial region thereof. The fourth lens is formed in a meniscus shape at a paraxial region thereof. The seventh lens is formed in a meniscus shape at a paraxial region thereof. The seventh lens has a specific focal length. The second lens is disposed away from the third lens by a specific distance.