Imaging Lens Aberration Correction via Parameter Optimization
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Solution Overview
Problem
Conventional imaging lenses for small cameras, such as smartphones, face challenges in achieving high resolution while maintaining a compact size and effectively correcting aberrations like chromatic aberration, astigmatism, and field curvature.
Innovation Solution
The imaging lens configuration includes a first lens group with positive and negative refractive powers, and a second lens group with specific focal length and Abbe's number ratios, optimized to minimize chromatic aberration and astigmatism, and ensure sufficient back focal length for proper image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of lenses is increased to achieve high resolution, then the imaging quality is improved, but the size of the imaging lens increases
Solution Approach 1:
The patent applies parameter changes by optimizing the focal length ratios between lenses (specifically f1/f and f2/f ratios) and selecting specific Abbe's numbers for lens materials. This allows achieving high resolution with a limited number of lenses by precisely controlling optical parameters rather than simply adding more lens elements.
Solution Approach 2:
The patent uses composite material principles by combining lenses with different Abbe's numbers (dispersive and non-dispersive lens combinations) to correct chromatic aberrations. This allows achieving high imaging quality without increasing the number of lenses, as the different material properties work together to correct multiple aberration types simultaneously.
2Length of stationary object
If the number of lenses is reduced to downsize the imaging lens, then the size is reduced, but the ability to correct aberrations deteriorates
Solution Approach 1:
The patent changes key optical parameters by establishing specific ratio relationships (f1/f between 0.3-0.8 and f2/f between 0.1-0.4) and controlling Abbe's numbers of individual lenses. These parameter optimizations enable a six-lens configuration to achieve aberration correction performance comparable to or better than conventional designs with more lenses.
Solution Approach 2:
The patent applies local quality by assigning specific functional roles to different lens groups: the first lens group (L1, L2, L3) primarily corrects chromatic aberrations and controls distortion, while the second lens group (L4, L5, L6) focuses on correcting astigmatism and field curvature. This localized functional distribution maximizes aberration correction efficiency with minimal lens count.
3Length of stationary object
If the distance from the first lens to the image plane is reduced to downsize the camera, then the camera size is reduced, but the back focal length becomes insufficient for proper image formation
Solution Approach 1:
The patent solves the back focal length problem by changing the dimensional relationship between lenses through optimized spacing ratios. By controlling the ratio of distances (d13/f and d46/f), the patent creates an optical path that achieves sufficient back focal length within a compact overall form factor, effectively decoupling camera size from back focal length requirements.
4Measurement precision
If the focal length ratios and Abbe's numbers are optimized to correct chromatic aberration and astigmatism, then the imaging quality is improved, but the design complexity increases
Solution Approach 1:
The patent simplifies design complexity by reducing the number of independent parameters to control. Instead of optimizing each lens individually, the patent focuses on key ratio parameters (f1/f, f2/f, d13/f, d46/f) and material properties (Abbe's numbers). This parameter reduction approach maintains high imaging quality while making the design process more manageable and manufacturable.
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 a compact imaging lens with high resolution and effective aberration correction, suitable for small cameras, ensuring bright and clear images without the need for additional electrical noise reduction circuits.
Implementation Method 1
a first lens group having positive refractive power; and a second lens group having negative refractive power
Implementation Method 2
when the whole lens system has a focal length f, the first lens has a focal length f1, the first lens has an Abbe's number νd1, the second lens has an Abbe's number νd2, and the third lens has an Abbe's number νd3
Data Source
AI summary
An imaging lens includes a first lens group and a second lens group, arranged from an object side to an image plane side. The first lens group includes a first lens having positive refractive power, a second lens having positive refractive power, and a third lens having at least one aspheric surface, arranged with a space in between. The second lens group includes a fourth lens having positive refractive power and at least one aspheric surface, a fifth lens having two aspheric surfaces, and a sixth lens having two aspheric surfaces, arranged with a space in between. The fifth lens is formed in a shape so that a curvature radius of the surface on the image plane side is positive near an optical axis. The sixth lens is formed in a shape so that a curvature radius of the surface on the object side is negative near an optical axis.