Six-Lens Imaging Lens Aberration Correction via Parameter Optimization
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Solution Overview
Problem
Existing imaging lenses for electronic cameras, such as on-vehicle and surveillance cameras, fail to achieve a small F number and adequate correction of various aberrations, leading to suboptimal performance in low light conditions and image resolution.
Innovation Solution
A six-lens imaging lens configuration with specific refractive power arrangements and conditional expressions is used, including a biconcave first lens, convex second lens, biconvex third lens, negative fourth lens, positive fifth lens, and negative sixth lens, with an aperture stop between the second and third lenses, to achieve a small F number and correct aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional six-lens configuration (negative, positive, positive, negative, positive, negative) is used, then the basic imaging function is achieved, but the F number cannot be sufficiently reduced and various aberrations are not adequately corrected
Solution Approach 1:
The patent applies parameter changes by optimizing the refractive indices and Abbe numbers of the lens materials. Specifically, it sets the refractive index of the second lens between 1.46 and 1.56, the third lens between 1.74 and 1.86, and the fourth lens between 1.46 and 1.56. The Abbe number of the second lens is set between 56 and 66, the third lens between 20 and 30, and the fourth lens between 56 and 66. These precise parameter specifications enable simultaneous achievement of small F number and excellent aberration correction.
2Measurement precision
If the number of pixels in the imaging element is increased, then the image resolution is improved, but the demand for aberration correction becomes more stringent and difficult to satisfy
Solution Approach 1:
The patent applies local quality by assigning different optical properties to different lenses in the system. Each lens is specifically designed with tailored refractive index and Abbe number characteristics suited to its position and function. The second lens uses low refractive index (1.46-1.56) and high Abbe number (56-66) for minimal chromatic aberration, the third lens uses high refractive index (1.74-1.86) and low Abbe number (20-30) for strong converging power with controlled dispersion, and the fourth lens mirrors the second lens's properties. This localized optimization of material properties enables the system to achieve excellent aberration correction across the entire field of view, supporting high-resolution imaging.
3Illumination intensity
If imaging in low light conditions is required, then a small F number is needed, but this makes aberration correction more difficult
Solution Approach 1:
The patent achieves small F number (enabling low light imaging) while maintaining excellent optical performance through precise parameter control of lens materials. The specific refractive index ranges (second lens: 1.46-1.56, third lens: 1.74-1.86, fourth lens: 1.46-1.56) and Abbe number ranges (second lens: 56-66, third lens: 20-30, fourth lens: 56-66) are optimized to balance light gathering capability with aberration correction, allowing the system to achieve both small F number and high image quality.
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 an imaging lens with a small F number and excellent optical performance, capable of producing high-resolution images with corrected aberrations, suitable for use in low light conditions.
Implementation Method 1
a second lens that is convex toward an image side and has a positive refractive power; a third lens that has a biconvex shape; a fourth lens that has a negative refractive power; a fifth lens that has a positive refractive power
Data Source
AI summary
Provided are an imaging lens, which has a small F number and in which various aberrations are satisfactorily corrected, and an imaging apparatus including the imaging lens.The imaging lens includes, in order from an object side: a first lens that has a biconcave shape; a second lens that is convex toward an image side and has a positive refractive power; a third lens that has a biconvex shape; a fourth lens that has a negative refractive power; a fifth lens that has a positive refractive power; and a sixth lens that has a negative refractive power. Assuming that L1f and L1r are paraxial radii of curvature of an object side surface and an image side surface of the first lens, Conditional Expression (1) is satisfied.0.1<(L1f+L1r)/(L1f−L1r)<0.8 (1)