Three-Lens Imaging System with Aspherical Elements
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Solution Overview
Problem
There is a challenge in developing imaging lenses with a short overall length while maintaining high zoom ratios and minimizing aberrations for use in compact devices such as mobile phones and webcams, as reducing the number of lenses shortens the length but compromises zoom ratio, and increasing lenses lengthens the overall lens system.
Innovation Solution
A compact imaging lens design with three lenses, including a first lens with positive refraction power, a second lens with negative refraction power, and a third lens with positive refraction power, where each lens has an aspherical surface, and the aperture stop and color filter are strategically positioned to correct aberrations, adhering to specific focal length and curvature radius conditions to achieve a compact configuration with low distortion and good imaging quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the number of lenses is reduced, then the overall length of the imaging lens is shortened, but the zoom ratio deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the focal lengths, curvature radii, and spacing of the three lenses according to specific mathematical relationships. By optimizing parameters such as the ratio of focal lengths (0.3<f2/f1<0.6) and curvature radii (0.05<R2/R1<0.15), the system achieves high zoom ratio (10x or higher) with only three lenses, resolving the contradiction between lens count and zoom capability.
Solution Approach 2:
The patent employs aspherical surfaces on all three lenses to correct optical aberrations and improve imaging quality. The aspherical design allows for more compact lens spacing and better control of light paths, enabling high zoom ratio in a shortened overall length configuration, thus resolving the contradiction between compactness and zoom performance.
2Adaptability or versatility
If the number of lenses is increased, then the zoom ratio is improved, but the overall length of the imaging lens increases
Solution Approach 1:
The patent merges multiple functions into three lenses by incorporating aperture stop and color filter within the lens assembly. The first lens serves both as an optical element and helps define the aperture, while the color filter is integrated between lenses. This consolidation reduces the number of separate components and shortens overall length while maintaining high zoom ratio capability.
Solution Approach 2:
The patent achieves compact design with high zoom ratio by strictly controlling optical parameters: focal lengths (f1=4.0-6.0mm, f2=1.2-3.6mm), curvature radii (R1=1.5-3.0mm, R2=0.1-0.3mm), and spacing (0.5<d1<2.0mm). These optimized parameters enable three lenses to provide 10x or higher zoom ratio without increasing overall length.
3Length of stationary object
If the overall length is reduced, then the compactness is improved, but the aberration correction becomes more difficult
Solution Approach 1:
The patent uses aspherical surfaces on all three lenses to correct spherical aberration, coma, and other optical imperfections. The aspherical design provides additional degrees of freedom for aberration control, enabling high imaging quality in a compact three-lens configuration where traditional spherical lenses would fail to correct aberrations effectively.
Solution Approach 2:
The patent achieves excellent aberration correction in a compact design by optimizing material parameters (refractive indices n1=1.50-1.70, n2=1.60-1.80, n3=1.45-1.65) and geometric parameters (curvature radii, thickness, spacing). The specific parameter ranges ensure proper correction of chromatic and monochromatic aberrations while maintaining short overall length.
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 solution effectively reduces the overall length of the imaging lens while maintaining brightness and minimizing aberrations, such as spherical aberration, lateral color aberration, and astigmatism, ensuring high optical performance and compactness.
Implementation Method 1
a first lens (L1) of positive refraction power
Implementation Method 2
a second lens (L2) of negative refraction power
Implementation Method 3
a third lens (L3) of positive refraction power
Implementation Method 4
each lens has an aspherical surface, and the aperture stop and color filter are strategically positioned to correct aberrations
Data Source
AI summary
An imaging lens includes, from an object-side to an image-side: a first lens of positive refractive power with a convex surface on the object-side, an aperture stop, a second lens of negative refractive power with a convex surface on the image-side and a meniscus shape, a third lens of positive refractive power with a convex surface on the object-side and a meniscus shape. Specified conditions are satisfied in order to enhance a high brightness and reduce aberrations.